80_FR_11902 80 FR 11859 - Special Conditions: Bombardier Aerospace, Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Alternate Fuel Tank Structural Lightning Protection Requirements

80 FR 11859 - Special Conditions: Bombardier Aerospace, Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Alternate Fuel Tank Structural Lightning Protection Requirements

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 80, Issue 43 (March 5, 2015)

Page Range11859-11863
FR Document2015-05047

These special conditions are issued for the Bombardier Aerospace Models BD-500-1A10 and BD-500-1A11 series airplanes. These airplanes will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is a nitrogen generation system (NGS) for all fuel tanks that actively reduces flammability exposure within the fuel tanks significantly below that required by the fuel tank flammability regulations. Among other benefits, the NGS significantly reduces the potential for fuel vapor ignition caused by lightning strikes. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

Federal Register, Volume 80 Issue 43 (Thursday, March 5, 2015)
[Federal Register Volume 80, Number 43 (Thursday, March 5, 2015)]
[Rules and Regulations]
[Pages 11859-11863]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-05047]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2014-0383; Special Conditions No. 25-578-SC]


Special Conditions: Bombardier Aerospace, Models BD-500-1A10 and 
BD-500-1A11 Series Airplanes; Alternate Fuel Tank Structural Lightning 
Protection Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued for the Bombardier 
Aerospace Models BD-500-1A10 and BD-500-1A11 series airplanes. These 
airplanes will have a novel or unusual design feature when compared to 
the state of technology envisioned in the airworthiness standards for 
transport category airplanes. This design feature is a nitrogen 
generation system (NGS) for all fuel tanks that actively reduces 
flammability exposure within the fuel tanks significantly below that 
required by the fuel tank flammability regulations. Among other 
benefits, the NGS significantly reduces the potential for fuel vapor 
ignition caused by lightning strikes. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. These special conditions contain the additional 
safety standards that the Administrator considers necessary to 
establish a level of safety equivalent to that established by the 
existing airworthiness standards.

DATES: This action is effective on Bombardier Aerospace on April 6, 
2015.

FOR FURTHER INFORMATION CONTACT: Margaret Langsted, FAA, Propulsion and 
Mechanical Systems Branch, ANM-112, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington, 98057-3356; telephone 425-227-2677; facsimile 425-227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On December 10, 2009, Bombardier Aerospace applied for a type 
certificate for their new Models BD-500-1A10 and BD-500-1A11 series 
airplanes (hereafter collectively referred to as ``CSeries''). The 
CSeries airplanes are swept-wing monoplanes with a composite wing fuel 
tank structure and an aluminum alloy fuselage that is sized for 5-
abreast seating. Passenger capacity is designated as 110 for the Model 
BD-500-1A10 and 125 for the Model BD-500-1A11. Maximum takeoff weight 
is 131,000 pounds for the Model BD-500-1A10 and 144,000 pounds for the 
Model BD-500-1A11.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, Bombardier Aerospace must show that the CSeries airplanes 
meet the applicable provisions of part 25 as amended by Amendments 25-1 
through 25-129.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the CSeries airplanes because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same or similar 
novel or unusual design feature, the special conditions would also 
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the CSeries airplanes must comply with the fuel vent and 
exhaust emission requirements of 14 CFR part 34 and the noise 
certification requirements of 14 CFR part 36, and the FAA must issue a 
finding of regulatory adequacy under Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.17.

Novel or Unusual Design Features

    The CSeries airplanes will incorporate the following novel or 
unusual design feature: A fuel tank nitrogen generation system (NGS) 
that is intended to control fuel tank flammability for all fuel tanks. 
This NGS is designed to provide a level of performance to all fuel 
tanks of the CSeries airplanes that applies the more stringent standard 
for warm day flammability performance applicable to normally emptied 
tanks within the fuselage contour from Sec.  25.981(b) and appendix M 
to part 25. An NGS actively reduces flammability exposure within the 
fuel tanks significantly below that required by the fuel tank 
flammability regulations. Among other benefits, the NGS significantly 
reduces the potential for fuel vapor ignition caused by lightning 
strikes. This high level of NGS performance for all fuel tanks is a 
novel or unusual design feature compared to the state of technology 
envisioned in the airworthiness standards for transport category 
airplanes.

Discussion

    The certification basis of the CSeries airplanes includes Sec.  
25.981, as amended by Amendment 25-125, as required by 14 CFR 26.37. 
This amendment includes the ignition prevention requirements in Sec.  
25.981(a), as amended by Amendment 25-102, and it includes revised 
flammability limits for all fuel tanks and new specific limitations on 
flammability for all fuel tanks as defined in Sec.  25.981(b), as 
amended by Amendment 25-125.

Ignition Source Prevention

    Section 25.981(a)(3) requires applicants to show that an ignition 
source in the fuel tank system could not result from any single 
failure, from any single failure in combination with any latent failure 
condition not shown to be extremely remote, or from any combination of 
failures not shown to be extremely improbable. This requirement was 
originally adopted in Amendment 25-102, and it requires the assumption 
that the fuel tanks are always flammable when showing that the 
probability of an ignition source being present is extremely remote. 
(Amendment 25-102 included Sec.  25.981(c) that required minimizing 
fuel tank flammability, and this was defined in the preamble as being 
equivalent to unheated aluminum fuel tanks located in the wing.) This 
requirement defines three types of scenarios that must be addressed in 
order to show compliance with Sec.  25.981(a)(3). The first scenario is 
that any single failure, regardless of the probability of occurrence of 
the failure, must not cause an ignition source. The second scenario is 
that any single failure, regardless of the probability of occurrence, 
in combination with any latent failure condition not shown to be at 
least extremely remote, must not cause an ignition source. The third 
scenario is that any combination of failures not shown to be extremely 
improbable must not cause an ignition source. Demonstration of 
compliance with this requirement would typically require a structured, 
quantitative safety analysis. Design areas that have latent failure 
conditions typically would be driven by these requirements to have 
multiple fault tolerance, or ``triple redundancy.'' This means that 
ignition

[[Page 11860]]

sources are still prevented even after two independent failures.

Flammability Limits

    Section 25.981(b) states that no fuel tank fleet average 
flammability exposure may exceed 3 percent of the flammability exposure 
evaluation time calculated using the method in part 25, appendix N, or 
the fleet average flammability of a fuel tank within the wing of the 
airplane being evaluated, whichever is greater. If the wing is not a 
conventional unheated aluminum wing, the analysis must be based on an 
assumed equivalent conventional construction unheated aluminum wing. In 
addition, for fuel tanks that are normally emptied during operation and 
that have any part of the tank located within the fuselage contour, the 
fleet average flammability for warm days (above 80 [deg]F) must be 
limited to 3 percent as calculated using the method in part 25, 
appendix M.

Application of Existing Regulations Inappropriate Due to Impracticality

    Since the issuance of Sec.  25.981(a)(3), as amended by Amendment 
25-102, the FAA has conducted certification projects in which 
applicants found it impractical to meet the requirements of that 
regulation for some areas of lightning protection for fuel tank 
structure. Partial exemptions were issued for these projects. These 
same difficulties exist for the CSeries project.
    The difficulty of designing multiple-fault-tolerant structure, and 
the difficulty of detecting failures of hidden structural design 
features in general, makes compliance with Sec.  25.981(a)(3) uniquely 
challenging and impractical for certain aspects of the electrical 
bonding of structural elements. Such bonding is needed to prevent 
occurrence of fuel tank ignition sources from lightning strikes. The 
effectiveness and fault tolerance of electrical bonding features for 
structural joints and fasteners is partially dependent on design 
features that cannot be effectively inspected or tested after assembly 
without damaging the structure, joint, or fastener. Examples of such 
features include a required interference fit between the shank of a 
fastener and the hole in which the fastener is installed, metal foil or 
mesh imbedded in composite material, a required clamping force provided 
by a fastener to pull two structural parts together, and a required 
faying surface bond between the flush surfaces of adjacent pieces of 
structural material such as in a wing skin joint or a mounting bracket 
installation. In addition, other features that can be physically 
inspected or tested may be located within the fuel tanks; therefore, it 
is not practical to inspect for failures of those features at short 
intervals. Examples of such failures include separation or loosening of 
cap seals over fastener ends and actual structural failures of internal 
fasteners. This inability to practically detect manufacturing errors 
and failures of structural design features critical to lightning 
protection results in degraded conditions that occur and remain in 
place for a very long time, possibly for the remaining life of the 
airplane.
    Accounting for such long failure latency periods in the system 
safety analysis required by Sec.  25.981(a)(3) would require multiple 
fault tolerance in the structural lightning protection design. As part 
of the design development activity for the CSeries, Bombardier has 
examined possible design provisions to provide multiple fault tolerance 
in the structural design to prevent ignition sources from occurring in 
the event of lightning attachment to the airplane in critical 
locations. Bombardier has concluded from this examination that 
providing multiple fault tolerance for some structural elements is not 
practical. Bombardier has also identified some areas of the CSeries 
design where it is impractical to provide even single fault tolerance 
in the structural design to prevent ignition sources from occurring in 
the event of lightning attachment after a single failure. The FAA has 
reviewed this examination with Bombardier in detail and has agreed that 
providing fault tolerance beyond that in the proposed CSeries design 
for these areas would be impractical.
    As a result of the CSeries and other certifications projects, the 
FAA has now determined that compliance with Sec.  25.981(a)(3) is 
impractical for some areas of lightning protection for fuel tank 
structure, and that application of Sec.  25.981(a)(3) to those design 
areas is therefore inappropriate. The FAA plans further rulemaking to 
revise Sec.  25.981(a)(3). As appropriate, the FAA plans to issue 
special conditions or exemptions, for certification projects 
progressing before the revision is complete. This is discussed in FAA 
Memorandum ANM-112-08-002, Policy on Issuance of Special Conditions and 
Exemptions Related to Lightning Protection of Fuel Tank Structure, 
dated May 26, 2009.

Application of Existing Regulations Inappropriate Due to Compensating 
Feature That Provides Equivalent Level of Safety

    Section 25.981(b) sets specific standards for fuel tank 
flammability as discussed above under ``Flammability Limits.'' Under 
that regulation, the fleet average flammability exposure of all fuel 
tanks on the CSeries airplanes may not exceed 3 percent of the 
flammability exposure evaluation time calculated using the method in 
part 25, appendix N, or the fleet average flammability of a wing main 
tank within an equivalent construction conventional unheated aluminum 
wing fuel tank, whichever is greater. The typical fleet average fuel 
tank flammability of fuel tanks located in the wing ranges between 1 
and 5 percent. If it is assumed that a CSeries equivalent conventional 
unheated aluminum wing fuel tank would not exceed a fleet average 
flammability time of 3 percent, the actual composite airplane wing fuel 
tank design would be required to comply with the 3 percent fleet 
average flammability standard, and therefore a means to reduce the 
flammability to 3 percent would be required. However, the proposed 
CSeries design includes NGS for all fuel tanks that will also be shown 
to meet the additional, more stringent warm day average flammability 
standard in part 25, appendix M, which is only required for normally 
emptied fuel tanks with some part of the tank within the fuselage 
contour. Fuel tanks that meet this requirement typically have average 
fuel tank flammability levels well below the required 3 percent.
    Since the proposed NGS for all fuel tanks on the CSeries provides 
performance that meets part 25, appendix M, the FAA has determined that 
the risk reduction provided by this additional performance will provide 
compensation for some relief from the ignition prevention requirements 
of Sec.  25.981(a)(3) while still establishing a level of safety 
equivalent to that established in the regulations.
    In determining the appropriate amount of relief from the ignition 
prevention requirements of Sec.  25.981(a), the FAA considered the 
original overall intent of Amendment 25-102, which was to ensure the 
prevention of catastrophic events due to fuel tank vapor explosion. 
These special conditions are intended to achieve that objective through 
a prescriptive requirement that fault tolerance (with respect to the 
creation of an ignition source) be provided for all structural 
lightning protection design features where providing such fault 
tolerance is

[[Page 11861]]

practical, and through a performance-based standard for the risk due to 
any single failure vulnerability that exists in the design. In 
addition, for any structural lightning protection design features for 
which Bombardier shows that providing fault tolerance is impractical, 
these special conditions would require Bombardier to show that a fuel 
tank vapor ignition event due to the summed risk of all non-fault-
tolerant design features is extremely improbable. Bombardier would be 
required to show that this safety objective is met by the proposed 
design using a structured system safety assessment similar to that 
currently used for demonstrating compliance with Sec. Sec.  25.901 and 
25.1309.
    Given these novel or unusual design features, and the compliance 
challenges noted earlier in this document, the FAA has determined that 
application of Sec.  25.981(a)(3) is inappropriate in that it is 
neither practical nor necessary to apply the ignition source prevention 
provisions of Sec.  25.981(a)(3) to the specific fuel tank structural 
lightning protection features of the Bombardier CSeries airplanes. 
However, without the Sec.  25.981(a)(3) provisions, the remaining 
applicable regulations in the CSeries certification basis would be 
inadequate to set an appropriate standard for fuel tank ignition 
prevention. Therefore, in accordance with provisions of Sec.  21.16, 
the FAA has determined that, instead of Sec.  25.981(a)(3), alternative 
fuel tank structural lightning protection requirements be applied to 
fuel tank lightning protection features that are integral to the 
airframe structure of the CSeries airplanes. These alternative 
requirements are intended to provide the level of safety intended by 
Sec.  25.981(a)(3), based on our recognition, as discussed above, that 
a highly effective NGS for the fuel tanks makes it unnecessary to 
assume that the fuel tank is always flammable. As discussed previously, 
the assumption that the fuel tanks are always flammable was required 
when demonstrating compliance to the ignition prevention requirements 
of Sec.  25.981(a)(3).
    One resulting difference between these special conditions and the 
Sec.  25.981(a)(3) provisions they are meant to replace is the outcome 
being prevented--fuel vapor ignition versus an ignition source. These 
special conditions acknowledge that the application of fuel tank 
flammability performance standards will reduce fuel tank flammability 
to an extent that it is appropriate to consider the beneficial effects 
of flammability reduction when considering design areas where it is 
impractical to comply with Sec.  25.981(a)(3).
    One of the core requirements of these special conditions is a 
prescriptive requirement that structural lightning protection design 
features must be fault tolerant. (An exception wherein Bombardier can 
show that providing fault tolerance is impractical, and associated 
requirements, is discussed below.) The other core requirement is that 
Bombardier must show that the design, manufacturing processes, and 
Airworthiness Limitations section of the Instructions for Continued 
Airworthiness include all practical measures to prevent, and detect and 
correct, failures of structural lightning protection features due to 
manufacturing variability, aging, wear, corrosion, and likely damage. 
The FAA has determined that, if these core requirements are met, a fuel 
tank vapor ignition event due to lightning is not anticipated to occur 
in the life of the airplane fleet. This conclusion is based on the fact 
that a critical lightning strike to any given airplane is itself a 
remote event, and on the fact that fuel tanks must be shown to be 
flammable for only a relatively small portion of the fleet operational 
life.
    For any non-fault-tolerant features proposed in the design, 
Bombardier must show that eliminating these features or making them 
fault tolerant is impractical. The requirements and considerations for 
showing it is impractical to provide fault tolerance are described in 
FAA Memorandum ANM-112-08-002. This requirement is intended to minimize 
the number of non-fault tolerant features in the design.
    For areas of the design where Bombardier shows that providing fault 
tolerant structural lightning protection features is impractical, non-
fault-tolerant features will be allowed provided Bombardier can show 
that a fuel tank vapor ignition event due to the non-fault-tolerant 
features is extremely improbable when the sum of probabilities of those 
events due to all non-fault-tolerant features is considered. Bombardier 
will be required to submit a structured, quantitative assessment of 
fleet average risk for a fuel tank vapor ignition event due to all non-
fault-tolerant design features included in the design. This will 
require determination of the number of non-fault tolerant design 
features, estimates of the probability of the failure of each non-
fault-tolerant design feature, and estimates of the exposure time for 
those failures. This analysis must include failures due to 
manufacturing variability, aging, wear, corrosion, and likely damage.
    It is acceptable to consider the probability of fuel tank 
flammability, the probability of a lightning strike to the airplane, 
the probability of a lightning strike to specific zones of the airplane 
(for example, Zone 2 behind the nacelle, but not a specific location or 
feature), and a distribution of lightning strike amplitude in 
performing the assessment provided the associated assumptions are 
acceptable to the FAA. The analysis must account for any dependencies 
among these factors, if they are used. The assessment must also account 
for operation with inoperative features and systems, including any 
proposed or anticipated dispatch relief. This risk assessment 
requirement is intended to ensure that an acceptable level of safety is 
provided given the non-fault-tolerant features in the proposed design.
    Part 25, appendix N, as adopted in Amendment 25-125, in conjunction 
with these special conditions, constitutes the standard for how to 
determine flammability probability. In performing the safety analysis 
required by these special conditions, relevant Sec.  25.981(a)(3) 
compliance guidance is still applicable. Appropriate credit for the 
conditional probability of environmental or operational conditions 
occurring is normally limited to those provisions involving multiple 
failures, and this type of credit is not normally allowed in evaluation 
of single failures. However, these special conditions would allow 
consideration of the probability of occurrence of lightning attachment 
and flammable conditions when assessing the probability of structural 
failures resulting in a fuel tank vapor ignition event.
    The FAA understands that lightning protection safety for airplane 
structure is inherently different from lightning protection for 
systems. We intend to apply these special conditions only to structural 
lightning protection features of fuel systems. We do not intend to 
apply the alternative standards used under these special conditions to 
other areas of the airplane design evaluation.

Requirements Provide Equivalent Level of Safety

    In recognition of the unusual design feature discussed above, and 
the impracticality of requiring multiple fault tolerance for lightning 
protection of certain aspects of fuel tank structure, the FAA has 
determined that a level of safety that is equivalent to direct 
compliance with Sec.  25.981(a)(3) will be achieved for the CSeries by 
applying these requirements. The FAA considers that, instead of only 
concentrating on fault tolerance for ignition source prevention, 
significantly reducing fuel tank flammability exposure in addition

[[Page 11862]]

to preventing ignition sources is a better approach to lightning 
protection for the fuel tanks. In addition, the level of average fuel 
tank flammability achieved by compliance with these special conditions 
is low enough that it is not appropriate or accurate to assume in a 
safety analysis that the fuel tanks may always be flammable.
    Section 25.981(b), as amended by Amendment 25-125, sets limits on 
the allowable fuel tank flammability for the CSeries airplanes. 
Paragraph 2(a) of these special conditions applies the more stringent 
standard for warm day flammability performance applicable to normally 
emptied tanks within the fuselage contour from Sec.  25.981(b) and part 
25, appendix M, to all of the fuel tanks of the CSeries airplanes.
    Because of the more stringent fuel tank flammability requirements 
in these special conditions, and because the flammability state of a 
fuel tank is independent of the various failures of structural elements 
that could lead to an ignition source in the event of lightning 
attachment, the FAA has agreed that it is appropriate in this case to 
allow treatment of flammability as an independent factor in the safety 
analysis. The positive control of flammability and the lower 
flammability that is required by these special conditions exceeds the 
minimum requirements of Sec.  25.981(b). This offsets a reduction of 
the stringent standard for ignition source prevention in Sec.  
25.981(a)(3), which assumes that the fuel tank is flammable at all 
times.
    Given the stringent requirements for fuel tank flammability, the 
fuel vapor ignition prevention and the ignition source prevention 
requirements in these special conditions will prevent ``. . . 
catastrophic failure . . . due to ignition of fuel or vapors'' as 
stated in Sec.  25.981(a). Thus, the overall level of safety achieved 
by these special conditions is considered equivalent to that which 
would be required by compliance with Sec.  25.981(a)(3) and (b).

Discussion of Comments

    Notice of proposed special conditions No. 25-14-05 for the 
Bombardier CSeries airplanes was published in the Federal Register on 
July 25, 2014 (79 FR 43318). No comments were received, and the special 
conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Models BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier 
Aerospace apply at a later date for a change to the type certificate to 
include another model incorporating the same novel or unusual design 
feature, the special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on two model series of airplanes. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Bombardier Aerospace Models BD-500-
1A10 and BD-500-1A11 series airplanes.

Alternate Fuel Tank Structural Lightning Protection Requirements

1. Definitions

    Most of the terms used in these special conditions either have the 
common dictionary meaning or are defined in Advisory Circular 25.1309-
1A, System Design and Analysis, dated June 21, 1988. The following 
definitions are the only terms intended to have a specialized meaning 
when used in these special conditions:
    (a) Basic Airframe Structure. Includes design elements such as 
structural members, structural joint features, and fastener systems 
including airplane skins, ribs, spars, stringers, etc., and associated 
fasteners, joints, coatings, and sealant. Basic airframe structure may 
also include those structural elements that are expected to be removed 
for maintenance, such as exterior fuel tank access panels and fairing 
attachment features, provided maintenance errors that could compromise 
associated lightning protection features would be evident upon an 
exterior preflight inspection of the airplane and would be corrected 
prior to flight.
    (b) Permanent Systems Supporting Structure. Includes static, 
permanently attached structural parts (such as brackets) that are used 
to support system elements. It does not include any part intended to be 
removed, or any joint intended to be separated, to maintain or replace 
system elements or other parts, unless that part removal or joint 
separation is accepted by the FAA as being extremely remote.
    (c) Manufacturing Variability. Includes tolerances and variability 
allowed by the design and production specifications as well as 
anticipated errors or escapes from the manufacturing and inspection 
processes.
    (d) Extremely Remote. Conditions that are not anticipated to occur 
to each airplane during its total life, but which may occur a few times 
when considering the total operational life of all airplanes of one 
type. Extremely remote conditions are those having an average 
probability per flight hour on the order of 1 x 10-7 or 
less, but greater than on the order of 1 x 10-9.
    (e) Extremely Improbable. Conditions that are so unlikely that they 
are not anticipated to occur during the entire operational life of all 
airplanes of one type. Extremely improbable conditions are those having 
an average probability per flight hour of the order of 1 x 
10-9 or less.

2. Alternative Fuel Tank Structural Lightning Protection Requirements

    For lightning protection features that are integral to fuel tank 
basic airframe structure or permanent systems supporting structure, as 
defined in Special Condition No. 1, ``Definitions,'' for which 
Bombardier shows and the FAA finds compliance with Sec.  25.981(a)(3) 
to be impractical, the following requirements may be applied in lieu of 
the requirements of Sec.  25.981(a)(3):
    (a) Bombardier must show that the airplane design meets the 
requirements of part 25, appendix M, as amended by Amendment 25-125, 
for all fuel tanks installed on the airplane.
    (b) Bombardier must show that the design includes at least two 
independent, effective, and reliable lightning protection features (or 
sets of features) such that fault tolerance to prevent lightning-
related ignition sources is provided for each area of the structural 
design proposed to be shown compliant with these special conditions in 
lieu of compliance with the requirements of Sec.  25.981(a)(3). Fault 
tolerance is not required for any specific design feature if:
    (1) For that feature, providing fault tolerance is shown to be 
impractical, and
    (2) Fuel tank vapor ignition due to that feature and all other non-
fault-tolerant features, when their fuel tank vapor ignition event 
probabilities are summed, is shown to be extremely improbable.

[[Page 11863]]

    (c) Bombardier must perform an analysis to show that the design, 
manufacturing processes, and the airworthiness limitations section of 
the instructions for continued airworthiness include all practical 
measures to prevent, and detect and correct, failures of structural 
lightning protection features due to manufacturing variability, aging, 
wear, corrosion, and likely damage.

    Issued in Renton, Washington, on February 25, 2015.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-05047 Filed 3-4-15; 8:45 am]
BILLING CODE 4910-13-P



                                                                   Federal Register / Vol. 80, No. 43 / Thursday, March 5, 2015 / Rules and Regulations                                         11859

                                                *      *     *       *      *                           monoplanes with a composite wing fuel                 regulations. Among other benefits, the
                                                [FR Doc. 2015–05061 Filed 3–4–15; 08:45 am]             tank structure and an aluminum alloy                  NGS significantly reduces the potential
                                                BILLING CODE 6450–01–P                                  fuselage that is sized for 5-abreast                  for fuel vapor ignition caused by
                                                                                                        seating. Passenger capacity is designated             lightning strikes. This high level of NGS
                                                                                                        as 110 for the Model BD–500–1A10 and                  performance for all fuel tanks is a novel
                                                DEPARTMENT OF TRANSPORTATION                            125 for the Model BD–500–1A11.                        or unusual design feature compared to
                                                                                                        Maximum takeoff weight is 131,000                     the state of technology envisioned in the
                                                Federal Aviation Administration                         pounds for the Model BD–500–1A10                      airworthiness standards for transport
                                                                                                        and 144,000 pounds for the Model BD–                  category airplanes.
                                                14 CFR Part 25                                          500–1A11.
                                                                                                                                                              Discussion
                                                [Docket No. FAA–2014–0383; Special                      Type Certification Basis                                 The certification basis of the CSeries
                                                Conditions No. 25–578–SC]                                  Under the provisions of Title 14, Code             airplanes includes § 25.981, as amended
                                                                                                        of Federal Regulations (14 CFR) 21.17,                by Amendment 25–125, as required by
                                                Special Conditions: Bombardier
                                                                                                        Bombardier Aerospace must show that                   14 CFR 26.37. This amendment includes
                                                Aerospace, Models BD–500–1A10 and
                                                                                                        the CSeries airplanes meet the                        the ignition prevention requirements in
                                                BD–500–1A11 Series Airplanes;
                                                                                                        applicable provisions of part 25 as                   § 25.981(a), as amended by Amendment
                                                Alternate Fuel Tank Structural
                                                                                                        amended by Amendments 25–1 through                    25–102, and it includes revised
                                                Lightning Protection Requirements
                                                                                                        25–129.                                               flammability limits for all fuel tanks and
                                                AGENCY:  Federal Aviation                                  If the Administrator finds that the                new specific limitations on flammability
                                                Administration (FAA), DOT.                              applicable airworthiness regulations                  for all fuel tanks as defined in
                                                ACTION: Final special conditions.                       (i.e., 14 CFR part 25) do not contain                 § 25.981(b), as amended by Amendment
                                                                                                        adequate or appropriate safety standards              25–125.
                                                SUMMARY:    These special conditions are                for the CSeries airplanes because of a                Ignition Source Prevention
                                                issued for the Bombardier Aerospace                     novel or unusual design feature, special
                                                Models BD–500–1A10 and BD–500–                          conditions are prescribed under the                      Section 25.981(a)(3) requires
                                                1A11 series airplanes. These airplanes                  provisions of § 21.16.                                applicants to show that an ignition
                                                will have a novel or unusual design                        Special conditions are initially                   source in the fuel tank system could not
                                                feature when compared to the state of                   applicable to the model for which they                result from any single failure, from any
                                                technology envisioned in the                            are issued. Should the type certificate               single failure in combination with any
                                                airworthiness standards for transport                   for that model be amended later to                    latent failure condition not shown to be
                                                category airplanes. This design feature                 include any other model that                          extremely remote, or from any
                                                is a nitrogen generation system (NGS)                   incorporates the same or similar novel                combination of failures not shown to be
                                                for all fuel tanks that actively reduces                or unusual design feature, the special                extremely improbable. This requirement
                                                flammability exposure within the fuel                   conditions would also apply to the other              was originally adopted in Amendment
                                                tanks significantly below that required                 model under § 21.101.                                 25–102, and it requires the assumption
                                                by the fuel tank flammability                              In addition to the applicable                      that the fuel tanks are always flammable
                                                regulations. Among other benefits, the                  airworthiness regulations and special                 when showing that the probability of an
                                                NGS significantly reduces the potential                 conditions, the CSeries airplanes must                ignition source being present is
                                                for fuel vapor ignition caused by                       comply with the fuel vent and exhaust                 extremely remote. (Amendment 25–102
                                                lightning strikes. The applicable                       emission requirements of 14 CFR part                  included § 25.981(c) that required
                                                                                                        34 and the noise certification                        minimizing fuel tank flammability, and
                                                airworthiness regulations do not contain
                                                                                                        requirements of 14 CFR part 36, and the               this was defined in the preamble as
                                                adequate or appropriate safety standards
                                                                                                        FAA must issue a finding of regulatory                being equivalent to unheated aluminum
                                                for this design feature. These special
                                                                                                        adequacy under § 611 of Public Law 92–                fuel tanks located in the wing.) This
                                                conditions contain the additional safety
                                                                                                        574, the ‘‘Noise Control Act of 1972.’’               requirement defines three types of
                                                standards that the Administrator
                                                                                                           The FAA issues special conditions, as              scenarios that must be addressed in
                                                considers necessary to establish a level
                                                                                                        defined in 14 CFR 11.19, in accordance                order to show compliance with
                                                of safety equivalent to that established
                                                                                                        with § 11.38, and they become part of                 § 25.981(a)(3). The first scenario is that
                                                by the existing airworthiness standards.
                                                                                                        the type certification basis under                    any single failure, regardless of the
                                                DATES: This action is effective on                                                                            probability of occurrence of the failure,
                                                                                                        § 21.17.
                                                Bombardier Aerospace on April 6, 2015.                                                                        must not cause an ignition source. The
                                                FOR FURTHER INFORMATION CONTACT:                        Novel or Unusual Design Features                      second scenario is that any single
                                                Margaret Langsted, FAA, Propulsion                         The CSeries airplanes will incorporate             failure, regardless of the probability of
                                                and Mechanical Systems Branch, ANM–                     the following novel or unusual design                 occurrence, in combination with any
                                                112, Transport Airplane Directorate,                    feature: A fuel tank nitrogen generation              latent failure condition not shown to be
                                                Aircraft Certification Service, 1601 Lind               system (NGS) that is intended to control              at least extremely remote, must not
                                                Avenue SW., Renton, Washington,                         fuel tank flammability for all fuel tanks.            cause an ignition source. The third
                                                98057–3356; telephone 425–227–2677;                     This NGS is designed to provide a level               scenario is that any combination of
                                                facsimile 425–227–1149.                                 of performance to all fuel tanks of the               failures not shown to be extremely
                                                SUPPLEMENTARY INFORMATION:                              CSeries airplanes that applies the more               improbable must not cause an ignition
                                                                                                        stringent standard for warm day                       source. Demonstration of compliance
mstockstill on DSK4VPTVN1PROD with RULES




                                                Background                                              flammability performance applicable to                with this requirement would typically
                                                  On December 10, 2009, Bombardier                      normally emptied tanks within the                     require a structured, quantitative safety
                                                Aerospace applied for a type certificate                fuselage contour from § 25.981(b) and                 analysis. Design areas that have latent
                                                for their new Models BD–500–1A10 and                    appendix M to part 25. An NGS actively                failure conditions typically would be
                                                BD–500–1A11 series airplanes (hereafter                 reduces flammability exposure within                  driven by these requirements to have
                                                collectively referred to as ‘‘CSeries’’).               the fuel tanks significantly below that               multiple fault tolerance, or ‘‘triple
                                                The CSeries airplanes are swept-wing                    required by the fuel tank flammability                redundancy.’’ This means that ignition


                                           VerDate Sep<11>2014   17:52 Mar 04, 2015   Jkt 235001   PO 00000   Frm 00003   Fmt 4700   Sfmt 4700   E:\FR\FM\05MRR1.SGM   05MRR1


                                                11860              Federal Register / Vol. 80, No. 43 / Thursday, March 5, 2015 / Rules and Regulations

                                                sources are still prevented even after                  physically inspected or tested may be                 Application of Existing Regulations
                                                two independent failures.                               located within the fuel tanks; therefore,             Inappropriate Due to Compensating
                                                Flammability Limits                                     it is not practical to inspect for failures           Feature That Provides Equivalent Level
                                                                                                        of those features at short intervals.                 of Safety
                                                   Section 25.981(b) states that no fuel                Examples of such failures include
                                                tank fleet average flammability exposure                                                                         Section 25.981(b) sets specific
                                                                                                        separation or loosening of cap seals over             standards for fuel tank flammability as
                                                may exceed 3 percent of the
                                                                                                        fastener ends and actual structural                   discussed above under ‘‘Flammability
                                                flammability exposure evaluation time
                                                                                                        failures of internal fasteners. This                  Limits.’’ Under that regulation, the fleet
                                                calculated using the method in part 25,
                                                appendix N, or the fleet average                        inability to practically detect                       average flammability exposure of all
                                                flammability of a fuel tank within the                  manufacturing errors and failures of                  fuel tanks on the CSeries airplanes may
                                                wing of the airplane being evaluated,                   structural design features critical to                not exceed 3 percent of the flammability
                                                whichever is greater. If the wing is not                lightning protection results in degraded              exposure evaluation time calculated
                                                a conventional unheated aluminum                        conditions that occur and remain in                   using the method in part 25, appendix
                                                wing, the analysis must be based on an                  place for a very long time, possibly for              N, or the fleet average flammability of a
                                                assumed equivalent conventional                         the remaining life of the airplane.                   wing main tank within an equivalent
                                                construction unheated aluminum wing.                                                                          construction conventional unheated
                                                                                                           Accounting for such long failure
                                                In addition, for fuel tanks that are                                                                          aluminum wing fuel tank, whichever is
                                                                                                        latency periods in the system safety                  greater. The typical fleet average fuel
                                                normally emptied during operation and                   analysis required by § 25.981(a)(3)
                                                that have any part of the tank located                                                                        tank flammability of fuel tanks located
                                                                                                        would require multiple fault tolerance                in the wing ranges between 1 and 5
                                                within the fuselage contour, the fleet                  in the structural lightning protection
                                                average flammability for warm days                                                                            percent. If it is assumed that a CSeries
                                                                                                        design. As part of the design                         equivalent conventional unheated
                                                (above 80 °F) must be limited to 3
                                                                                                        development activity for the CSeries,                 aluminum wing fuel tank would not
                                                percent as calculated using the method
                                                in part 25, appendix M.                                 Bombardier has examined possible                      exceed a fleet average flammability time
                                                                                                        design provisions to provide multiple                 of 3 percent, the actual composite
                                                Application of Existing Regulations                     fault tolerance in the structural design              airplane wing fuel tank design would be
                                                Inappropriate Due to Impracticality                     to prevent ignition sources from                      required to comply with the 3 percent
                                                   Since the issuance of § 25.981(a)(3), as             occurring in the event of lightning                   fleet average flammability standard, and
                                                amended by Amendment 25–102, the                        attachment to the airplane in critical                therefore a means to reduce the
                                                FAA has conducted certification                         locations. Bombardier has concluded                   flammability to 3 percent would be
                                                projects in which applicants found it                   from this examination that providing                  required. However, the proposed
                                                impractical to meet the requirements of                 multiple fault tolerance for some                     CSeries design includes NGS for all fuel
                                                that regulation for some areas of                       structural elements is not practical.                 tanks that will also be shown to meet
                                                lightning protection for fuel tank                      Bombardier has also identified some                   the additional, more stringent warm day
                                                structure. Partial exemptions were                      areas of the CSeries design where it is               average flammability standard in part
                                                issued for these projects. These same                   impractical to provide even single fault              25, appendix M, which is only required
                                                difficulties exist for the CSeries project.             tolerance in the structural design to                 for normally emptied fuel tanks with
                                                   The difficulty of designing multiple-                                                                      some part of the tank within the
                                                                                                        prevent ignition sources from occurring
                                                fault-tolerant structure, and the                                                                             fuselage contour. Fuel tanks that meet
                                                difficulty of detecting failures of hidden              in the event of lightning attachment
                                                                                                                                                              this requirement typically have average
                                                structural design features in general,                  after a single failure. The FAA has
                                                                                                                                                              fuel tank flammability levels well below
                                                makes compliance with § 25.981(a)(3)                    reviewed this examination with
                                                                                                                                                              the required 3 percent.
                                                uniquely challenging and impractical                    Bombardier in detail and has agreed that                 Since the proposed NGS for all fuel
                                                for certain aspects of the electrical                   providing fault tolerance beyond that in              tanks on the CSeries provides
                                                bonding of structural elements. Such                    the proposed CSeries design for these                 performance that meets part 25,
                                                bonding is needed to prevent                            areas would be impractical.                           appendix M, the FAA has determined
                                                occurrence of fuel tank ignition sources                   As a result of the CSeries and other               that the risk reduction provided by this
                                                from lightning strikes. The effectiveness               certifications projects, the FAA has now              additional performance will provide
                                                and fault tolerance of electrical bonding               determined that compliance with                       compensation for some relief from the
                                                features for structural joints and                      § 25.981(a)(3) is impractical for some                ignition prevention requirements of
                                                fasteners is partially dependent on                     areas of lightning protection for fuel                § 25.981(a)(3) while still establishing a
                                                design features that cannot be                          tank structure, and that application of               level of safety equivalent to that
                                                effectively inspected or tested after                   § 25.981(a)(3) to those design areas is               established in the regulations.
                                                assembly without damaging the                           therefore inappropriate. The FAA plans                   In determining the appropriate
                                                structure, joint, or fastener. Examples of                                                                    amount of relief from the ignition
                                                                                                        further rulemaking to revise
                                                such features include a required                                                                              prevention requirements of § 25.981(a),
                                                                                                        § 25.981(a)(3). As appropriate, the FAA
                                                interference fit between the shank of a                                                                       the FAA considered the original overall
                                                                                                        plans to issue special conditions or
                                                fastener and the hole in which the                                                                            intent of Amendment 25–102, which
                                                fastener is installed, metal foil or mesh               exemptions, for certification projects                was to ensure the prevention of
                                                imbedded in composite material, a                       progressing before the revision is                    catastrophic events due to fuel tank
                                                required clamping force provided by a                   complete. This is discussed in FAA                    vapor explosion. These special
mstockstill on DSK4VPTVN1PROD with RULES




                                                fastener to pull two structural parts                   Memorandum ANM–112–08–002,                            conditions are intended to achieve that
                                                together, and a required faying surface                 Policy on Issuance of Special Conditions              objective through a prescriptive
                                                bond between the flush surfaces of                      and Exemptions Related to Lightning                   requirement that fault tolerance (with
                                                adjacent pieces of structural material                  Protection of Fuel Tank Structure, dated              respect to the creation of an ignition
                                                such as in a wing skin joint or a                       May 26, 2009.                                         source) be provided for all structural
                                                mounting bracket installation. In                                                                             lightning protection design features
                                                addition, other features that can be                                                                          where providing such fault tolerance is


                                           VerDate Sep<11>2014   17:52 Mar 04, 2015   Jkt 235001   PO 00000   Frm 00004   Fmt 4700   Sfmt 4700   E:\FR\FM\05MRR1.SGM   05MRR1


                                                                   Federal Register / Vol. 80, No. 43 / Thursday, March 5, 2015 / Rules and Regulations                                         11861

                                                practical, and through a performance-                      One of the core requirements of these              the probability of a lightning strike to
                                                based standard for the risk due to any                  special conditions is a prescriptive                  the airplane, the probability of a
                                                single failure vulnerability that exists in             requirement that structural lightning                 lightning strike to specific zones of the
                                                the design. In addition, for any                        protection design features must be fault              airplane (for example, Zone 2 behind
                                                structural lightning protection design                  tolerant. (An exception wherein                       the nacelle, but not a specific location
                                                features for which Bombardier shows                     Bombardier can show that providing                    or feature), and a distribution of
                                                that providing fault tolerance is                       fault tolerance is impractical, and                   lightning strike amplitude in performing
                                                impractical, these special conditions                   associated requirements, is discussed                 the assessment provided the associated
                                                would require Bombardier to show that                   below.) The other core requirement is                 assumptions are acceptable to the FAA.
                                                a fuel tank vapor ignition event due to                 that Bombardier must show that the                    The analysis must account for any
                                                the summed risk of all non-fault-tolerant               design, manufacturing processes, and                  dependencies among these factors, if
                                                design features is extremely improbable.                Airworthiness Limitations section of the              they are used. The assessment must also
                                                Bombardier would be required to show                    Instructions for Continued                            account for operation with inoperative
                                                that this safety objective is met by the                Airworthiness include all practical                   features and systems, including any
                                                proposed design using a structured                      measures to prevent, and detect and                   proposed or anticipated dispatch relief.
                                                system safety assessment similar to that                correct, failures of structural lightning             This risk assessment requirement is
                                                currently used for demonstrating                        protection features due to                            intended to ensure that an acceptable
                                                compliance with §§ 25.901 and 25.1309.                  manufacturing variability, aging, wear,               level of safety is provided given the
                                                   Given these novel or unusual design                  corrosion, and likely damage. The FAA                 non-fault-tolerant features in the
                                                features, and the compliance challenges                 has determined that, if these core                    proposed design.
                                                noted earlier in this document, the FAA                 requirements are met, a fuel tank vapor                  Part 25, appendix N, as adopted in
                                                has determined that application of                      ignition event due to lightning is not                Amendment 25–125, in conjunction
                                                § 25.981(a)(3) is inappropriate in that it              anticipated to occur in the life of the               with these special conditions,
                                                is neither practical nor necessary to                   airplane fleet. This conclusion is based              constitutes the standard for how to
                                                apply the ignition source prevention                    on the fact that a critical lightning strike          determine flammability probability. In
                                                provisions of § 25.981(a)(3) to the                     to any given airplane is itself a remote              performing the safety analysis required
                                                specific fuel tank structural lightning                 event, and on the fact that fuel tanks                by these special conditions, relevant
                                                protection features of the Bombardier                   must be shown to be flammable for only                § 25.981(a)(3) compliance guidance is
                                                CSeries airplanes. However, without the                 a relatively small portion of the fleet               still applicable. Appropriate credit for
                                                § 25.981(a)(3) provisions, the remaining                operational life.                                     the conditional probability of
                                                applicable regulations in the CSeries                      For any non-fault-tolerant features                environmental or operational conditions
                                                certification basis would be inadequate                 proposed in the design, Bombardier                    occurring is normally limited to those
                                                to set an appropriate standard for fuel                 must show that eliminating these                      provisions involving multiple failures,
                                                tank ignition prevention. Therefore, in                 features or making them fault tolerant is             and this type of credit is not normally
                                                accordance with provisions of § 21.16,                  impractical. The requirements and                     allowed in evaluation of single failures.
                                                the FAA has determined that, instead of                 considerations for showing it is                      However, these special conditions
                                                § 25.981(a)(3), alternative fuel tank                   impractical to provide fault tolerance                would allow consideration of the
                                                structural lightning protection                         are described in FAA Memorandum                       probability of occurrence of lightning
                                                requirements be applied to fuel tank                    ANM–112–08–002. This requirement is                   attachment and flammable conditions
                                                lightning protection features that are                  intended to minimize the number of                    when assessing the probability of
                                                integral to the airframe structure of the               non-fault tolerant features in the design.            structural failures resulting in a fuel
                                                CSeries airplanes. These alternative                       For areas of the design where                      tank vapor ignition event.
                                                requirements are intended to provide                    Bombardier shows that providing fault                    The FAA understands that lightning
                                                the level of safety intended by                         tolerant structural lightning protection              protection safety for airplane structure
                                                § 25.981(a)(3), based on our recognition,               features is impractical, non-fault-                   is inherently different from lightning
                                                as discussed above, that a highly                       tolerant features will be allowed                     protection for systems. We intend to
                                                effective NGS for the fuel tanks makes                  provided Bombardier can show that a                   apply these special conditions only to
                                                it unnecessary to assume that the fuel                  fuel tank vapor ignition event due to the             structural lightning protection features
                                                tank is always flammable. As discussed                  non-fault-tolerant features is extremely              of fuel systems. We do not intend to
                                                previously, the assumption that the fuel                improbable when the sum of                            apply the alternative standards used
                                                tanks are always flammable was                          probabilities of those events due to all              under these special conditions to other
                                                required when demonstrating                             non-fault-tolerant features is considered.            areas of the airplane design evaluation.
                                                compliance to the ignition prevention                   Bombardier will be required to submit
                                                                                                                                                              Requirements Provide Equivalent Level
                                                requirements of § 25.981(a)(3).                         a structured, quantitative assessment of
                                                   One resulting difference between                     fleet average risk for a fuel tank vapor              of Safety
                                                these special conditions and the                        ignition event due to all non-fault-                    In recognition of the unusual design
                                                § 25.981(a)(3) provisions they are meant                tolerant design features included in the              feature discussed above, and the
                                                to replace is the outcome being                         design. This will require determination               impracticality of requiring multiple
                                                prevented—fuel vapor ignition versus                    of the number of non-fault tolerant                   fault tolerance for lightning protection
                                                an ignition source. These special                       design features, estimates of the                     of certain aspects of fuel tank structure,
                                                conditions acknowledge that the                         probability of the failure of each non-               the FAA has determined that a level of
                                                application of fuel tank flammability                   fault-tolerant design feature, and                    safety that is equivalent to direct
mstockstill on DSK4VPTVN1PROD with RULES




                                                performance standards will reduce fuel                  estimates of the exposure time for those              compliance with § 25.981(a)(3) will be
                                                tank flammability to an extent that it is               failures. This analysis must include                  achieved for the CSeries by applying
                                                appropriate to consider the beneficial                  failures due to manufacturing                         these requirements. The FAA considers
                                                effects of flammability reduction when                  variability, aging, wear, corrosion, and              that, instead of only concentrating on
                                                considering design areas where it is                    likely damage.                                        fault tolerance for ignition source
                                                impractical to comply with                                 It is acceptable to consider the                   prevention, significantly reducing fuel
                                                § 25.981(a)(3).                                         probability of fuel tank flammability,                tank flammability exposure in addition


                                           VerDate Sep<11>2014   17:52 Mar 04, 2015   Jkt 235001   PO 00000   Frm 00005   Fmt 4700   Sfmt 4700   E:\FR\FM\05MRR1.SGM   05MRR1


                                                11862              Federal Register / Vol. 80, No. 43 / Thursday, March 5, 2015 / Rules and Regulations

                                                to preventing ignition sources is a better              another model incorporating the same                  joint separation is accepted by the FAA
                                                approach to lightning protection for the                novel or unusual design feature, the                  as being extremely remote.
                                                fuel tanks. In addition, the level of                   special conditions would apply to that                   (c) Manufacturing Variability.
                                                average fuel tank flammability achieved                 model as well.                                        Includes tolerances and variability
                                                by compliance with these special                                                                              allowed by the design and production
                                                                                                        Conclusion
                                                conditions is low enough that it is not                                                                       specifications as well as anticipated
                                                appropriate or accurate to assume in a                    This action affects only certain novel              errors or escapes from the
                                                safety analysis that the fuel tanks may                 or unusual design features on two                     manufacturing and inspection
                                                always be flammable.                                    model series of airplanes. It is not a rule           processes.
                                                   Section 25.981(b), as amended by                     of general applicability.                                (d) Extremely Remote. Conditions that
                                                Amendment 25–125, sets limits on the                                                                          are not anticipated to occur to each
                                                allowable fuel tank flammability for the                List of Subjects in 14 CFR Part 25
                                                                                                                                                              airplane during its total life, but which
                                                CSeries airplanes. Paragraph 2(a) of                      Aircraft, Aviation safety, Reporting                may occur a few times when
                                                these special conditions applies the                    and recordkeeping requirements.                       considering the total operational life of
                                                more stringent standard for warm day                                                                          all airplanes of one type. Extremely
                                                                                                          The authority citation for these
                                                flammability performance applicable to                                                                        remote conditions are those having an
                                                                                                        special conditions is as follows:
                                                normally emptied tanks within the                                                                             average probability per flight hour on
                                                fuselage contour from § 25.981(b) and                     Authority: 49 U.S.C. 106(g), 40113, 44701,
                                                                                                        44702, 44704.                                         the order of 1 × 10¥7 or less, but greater
                                                part 25, appendix M, to all of the fuel                                                                       than on the order of 1 × 10¥9.
                                                tanks of the CSeries airplanes.                         The Special Conditions                                  (e) Extremely Improbable. Conditions
                                                   Because of the more stringent fuel                                                                         that are so unlikely that they are not
                                                tank flammability requirements in these                 ■ Accordingly, pursuant to the authority
                                                                                                                                                              anticipated to occur during the entire
                                                special conditions, and because the                     delegated to me by the Administrator,
                                                                                                                                                              operational life of all airplanes of one
                                                flammability state of a fuel tank is                    the following special conditions are
                                                                                                                                                              type. Extremely improbable conditions
                                                independent of the various failures of                  issued as part of the type certification
                                                                                                                                                              are those having an average probability
                                                structural elements that could lead to an               basis for Bombardier Aerospace Models
                                                                                                                                                              per flight hour of the order of 1 × 10¥9
                                                ignition source in the event of lightning               BD–500–1A10 and BD–500–1A11 series
                                                                                                                                                              or less.
                                                attachment, the FAA has agreed that it                  airplanes.
                                                is appropriate in this case to allow                                                                          2. Alternative Fuel Tank Structural
                                                                                                        Alternate Fuel Tank Structural
                                                treatment of flammability as an                                                                               Lightning Protection Requirements
                                                                                                        Lightning Protection Requirements
                                                independent factor in the safety                                                                                 For lightning protection features that
                                                analysis. The positive control of                       1. Definitions
                                                                                                                                                              are integral to fuel tank basic airframe
                                                flammability and the lower flammability                   Most of the terms used in these                     structure or permanent systems
                                                that is required by these special                       special conditions either have the                    supporting structure, as defined in
                                                conditions exceeds the minimum                          common dictionary meaning or are                      Special Condition No. 1, ‘‘Definitions,’’
                                                requirements of § 25.981(b). This offsets               defined in Advisory Circular 25.1309–                 for which Bombardier shows and the
                                                a reduction of the stringent standard for               1A, System Design and Analysis, dated                 FAA finds compliance with
                                                ignition source prevention in                           June 21, 1988. The following definitions              § 25.981(a)(3) to be impractical, the
                                                § 25.981(a)(3), which assumes that the                  are the only terms intended to have a                 following requirements may be applied
                                                fuel tank is flammable at all times.                    specialized meaning when used in these                in lieu of the requirements of
                                                   Given the stringent requirements for                 special conditions:                                   § 25.981(a)(3):
                                                fuel tank flammability, the fuel vapor
                                                                                                           (a) Basic Airframe Structure. Includes                (a) Bombardier must show that the
                                                ignition prevention and the ignition
                                                                                                        design elements such as structural                    airplane design meets the requirements
                                                source prevention requirements in these
                                                                                                        members, structural joint features, and               of part 25, appendix M, as amended by
                                                special conditions will prevent ‘‘. . .
                                                                                                        fastener systems including airplane                   Amendment 25–125, for all fuel tanks
                                                catastrophic failure . . . due to ignition
                                                                                                        skins, ribs, spars, stringers, etc., and              installed on the airplane.
                                                of fuel or vapors’’ as stated in
                                                                                                        associated fasteners, joints, coatings,                  (b) Bombardier must show that the
                                                § 25.981(a). Thus, the overall level of
                                                                                                        and sealant. Basic airframe structure                 design includes at least two
                                                safety achieved by these special
                                                                                                        may also include those structural                     independent, effective, and reliable
                                                conditions is considered equivalent to
                                                                                                        elements that are expected to be                      lightning protection features (or sets of
                                                that which would be required by
                                                                                                        removed for maintenance, such as                      features) such that fault tolerance to
                                                compliance with § 25.981(a)(3) and (b).
                                                                                                        exterior fuel tank access panels and                  prevent lightning-related ignition
                                                Discussion of Comments                                  fairing attachment features, provided                 sources is provided for each area of the
                                                  Notice of proposed special conditions                 maintenance errors that could                         structural design proposed to be shown
                                                No. 25–14–05 for the Bombardier                         compromise associated lightning                       compliant with these special conditions
                                                CSeries airplanes was published in the                  protection features would be evident                  in lieu of compliance with the
                                                Federal Register on July 25, 2014 (79 FR                upon an exterior preflight inspection of              requirements of § 25.981(a)(3). Fault
                                                43318). No comments were received,                      the airplane and would be corrected                   tolerance is not required for any specific
                                                and the special conditions are adopted                  prior to flight.                                      design feature if:
                                                as proposed.                                               (b) Permanent Systems Supporting                      (1) For that feature, providing fault
                                                                                                        Structure. Includes static, permanently               tolerance is shown to be impractical,
mstockstill on DSK4VPTVN1PROD with RULES




                                                Applicability                                           attached structural parts (such as                    and
                                                  As discussed above, these special                     brackets) that are used to support                       (2) Fuel tank vapor ignition due to
                                                conditions are applicable to the Models                 system elements. It does not include any              that feature and all other non-fault-
                                                BD–500–1A10 and BD–500–1A11 series                      part intended to be removed, or any                   tolerant features, when their fuel tank
                                                airplanes. Should Bombardier                            joint intended to be separated, to                    vapor ignition event probabilities are
                                                Aerospace apply at a later date for a                   maintain or replace system elements or                summed, is shown to be extremely
                                                change to the type certificate to include               other parts, unless that part removal or              improbable.


                                           VerDate Sep<11>2014   18:48 Mar 04, 2015   Jkt 235001   PO 00000   Frm 00006   Fmt 4700   Sfmt 4700   E:\FR\FM\05MRR1.SGM   05MRR1


                                                                   Federal Register / Vol. 80, No. 43 / Thursday, March 5, 2015 / Rules and Regulations                                        11863

                                                   (c) Bombardier must perform an                       Background                                            3E001 (limited to ‘‘technology’’ for
                                                analysis to show that the design,                                                                             items classified under 3C002 and 3C004
                                                                                                        Authorization Validated End-User
                                                manufacturing processes, and the                                                                              and ‘‘technology’’ for use consistent
                                                airworthiness limitations section of the                   Validated End-Users (VEUs) are                     with the International Technology
                                                instructions for continued airworthiness                designated entities located in eligible               Roadmap for Semiconductors process
                                                include all practical measures to                       destinations to which eligible items may              for items classified under ECCNs 3B001
                                                prevent, and detect and correct, failures               be exported, reexported, or transferred               and 3B002).
                                                of structural lightning protection                      (in-country) under a general
                                                                                                                                                              Export Administration Act
                                                features due to manufacturing                           authorization instead of a license. The
                                                variability, aging, wear, corrosion, and                names of the VEUs, as well as the dates                  Since August 21, 2001, the Export
                                                likely damage.                                          they were so designated, and their                    Administration Act of 1979, as
                                                                                                        respective eligible destinations and                  amended, has been in lapse. However,
                                                  Issued in Renton, Washington, on February
                                                                                                        items are identified in Supplement No.                the President, through Executive Order
                                                25, 2015.
                                                                                                        7 to Part 748 of the EAR. Under the                   13222 of August 17, 2001, 3 CFR 2001
                                                Jeffrey E. Duven,                                                                                             Comp., p. 783 (2002), as amended by
                                                                                                        terms described in that supplement,
                                                Manager, Transport Airplane Directorate,                                                                      Executive Order 13637 of March 8,
                                                Aircraft Certification Service.
                                                                                                        VEUs may obtain eligible items without
                                                                                                        an export license from BIS, in                        2013, 78 FR 16129 (March 13, 2013),
                                                [FR Doc. 2015–05047 Filed 3–4–15; 8:45 am]                                                                    and as extended by the Notice of August
                                                                                                        conformity with Section 748.15 of the
                                                BILLING CODE 4910–13–P
                                                                                                        EAR. Eligible items vary between VEUs                 7, 2014, 79 FR 46959 (August 11, 2014)
                                                                                                        and may include commodities, software,                has continued the EAR in effect under
                                                                                                        and technology, except those controlled               the International Emergency Economic
                                                                                                        for missile technology or crime control               Powers Act (50 U.S.C. 1701 et seq.). BIS
                                                DEPARTMENT OF COMMERCE                                                                                        continues to carry out the provisions of
                                                                                                        reasons on the Commerce Control List
                                                                                                        (CCL) (part 774 of the EAR).                          the Export Administration Act, as
                                                Bureau of Industry and Security                                                                               appropriate and to the extent permitted
                                                                                                           VEUs are reviewed and approved by
                                                                                                        the U.S. Government in accordance with                by law, pursuant to Executive Order
                                                15 CFR Part 748                                                                                               13222, as amended by Executive Order
                                                                                                        the provisions of Section 748.15 and
                                                                                                        Supplement Nos. 8 and 9 to Part 748 of                13637.
                                                [Docket No. 150206120–5120–01]
                                                                                                        the EAR. The End-User Review                          Rulemaking Requirements
                                                                                                        Committee (ERC), composed of
                                                RIN 0694–AG50                                                                                                    1. Executive Orders 13563 and 12866
                                                                                                        representatives from the Departments of               direct agencies to assess all costs and
                                                                                                        State, Defense, Energy, and Commerce,                 benefits of available regulatory
                                                Amendments to Existing Validated                        and other agencies, as appropriate, is
                                                End-User Authorization in the People’s                                                                        alternatives and, if regulation is
                                                                                                        responsible for administering the VEU                 necessary, to select regulatory
                                                Republic of China: Samsung China                        program. BIS amended the EAR in a
                                                Semiconductor Co. Ltd.                                                                                        approaches that maximize net benefits
                                                                                                        final rule published on June 19, 2007                 (including potential economic,
                                                AGENCY:  Bureau of Industry and                         (72 FR 33646) to create Authorization                 environmental, public health and safety
                                                Security, Commerce.                                     VEU.                                                  effects, distributive impacts, and
                                                                                                        Amendment to Existing VEU                             equity). Executive Order 13563
                                                ACTION:   Final rule.
                                                                                                        Authorization for Samsung China                       emphasizes the importance of
                                                SUMMARY:    In this rule, the Bureau of                 Semiconductor Co. Ltd (Samsung                        quantifying both costs and benefits,
                                                Industry and Security (BIS) amends the                  China) in the People’s Republic of                    reducing costs, harmonizing rules, and
                                                Export Administration Regulations                       China (PRC)                                           promoting flexibility. This rule has been
                                                (EAR) to revise the existing                                                                                  determined to be not significant for
                                                                                                        Revision to the List of ‘‘Eligible Items (by          purposes of Executive Order 12866.
                                                authorization for Validated End User                    ECCN)’’ for Samsung China                                2. This rule involves collections
                                                Samsung China Semiconductor Co. Ltd.
                                                                                                           In this final rule, BIS amends                     previously approved by the Office of
                                                (Samsung China) in the People’s
                                                                                                        Supplement No. 7 to Part 748 to add                   Management and Budget (OMB) under
                                                Republic of China (PRC). Specifically,
                                                                                                        two Export Control Classification                     Control Number 0694–0088, ‘‘Multi-
                                                BIS amends Supplement No. 7 to Part
                                                                                                        Numbers (ECCNs), 2B006.a and                          Purpose Application,’’ which carries a
                                                748 of the EAR to add two items to
                                                                                                        2B006.b.1.d, to the list of items that may            burden hour estimate of 43.8 minutes to
                                                Samsung China’s eligible items that may
                                                                                                        be exported, reexported or transferred                prepare and submit form BIS–748; and
                                                be exported, reexported or transferred
                                                                                                        (in-country) to Samsung China’s facility              for recordkeeping, reporting and review
                                                (in country) to the company’s eligible
                                                                                                        in the PRC under Authorization VEU.                   requirements in connection with
                                                facilities (also known as ‘‘eligible
                                                                                                        The revised list of eligible items for                Authorization VEU, which carries an
                                                destinations’’) in the PRC.
                                                                                                        Samsung China is as follows:                          estimated burden of 30 minutes per
                                                DATES:   This rule is effective March 5,                                                                      submission. This rule is expected to
                                                2015.                                                   Eligible Items (by ECCN) That May Be                  result in a decrease in license
                                                                                                        Exported, Reexported or Transferred                   applications submitted to BIS. Total
                                                FOR FURTHER INFORMATION CONTACT:   Mi-                  (In-Country) to the Eligible Destination              burden hours associated with the
                                                Yong Kim, Chair, End-User Review                        Identified Under Samsung China                        Paperwork Reduction Act of 1995 (44
mstockstill on DSK4VPTVN1PROD with RULES




                                                Committee, Office of the Assistant                      Semiconductor Co. Ltd.’s Validated                    U.S.C. 3501 et seq.) (PRA) and OMB
                                                Secretary, Export Administration,                       End-User Authorization                                Control Number 0694–0088 are not
                                                Bureau of Industry and Security, U.S.                     1C350.c.3, 1C350.d.7, 2B006.a,                      expected to increase significantly as a
                                                Department of Commerce, Phone: 202–                     2B006.b.1.d, 2B230, 2B350.d.2,                        result of this rule. Notwithstanding any
                                                482-5991; Fax: 202–482–3911; Email:                     2B350.g.3, 2B350.i.3, 3A233, 3B001.a.1,               other provisions of law, no person is
                                                ERC@bis.doc.gov.                                        3B001.b, 3B001.c, 3B001.e, 3B001.f,                   required to respond to, nor be subject to
                                                SUPPLEMENTARY INFORMATION:                              3B001.h, 3C002, 3C004, 3D002, and                     a penalty for failure to comply with a


                                           VerDate Sep<11>2014   21:54 Mar 04, 2015   Jkt 235001   PO 00000   Frm 00007   Fmt 4700   Sfmt 4700   E:\FR\FM\05MRR1.SGM   05MRR1



Document Created: 2015-12-18 12:09:32
Document Modified: 2015-12-18 12:09:32
CategoryRegulatory Information
CollectionFederal Register
sudoc ClassAE 2.7:
GS 4.107:
AE 2.106:
PublisherOffice of the Federal Register, National Archives and Records Administration
SectionRules and Regulations
ActionFinal special conditions.
DatesThis action is effective on Bombardier Aerospace on April 6, 2015.
ContactMargaret Langsted, FAA, Propulsion and Mechanical Systems Branch, ANM-112, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-3356; telephone 425-227-2677; facsimile 425-227-1149.
FR Citation80 FR 11859 
CFR AssociatedAircraft; Aviation Safety and Reporting and Recordkeeping Requirements

2025 Federal Register | Disclaimer | Privacy Policy
USC | CFR | eCFR