83 FR 466 - Special Conditions: Airbus Model A330-841 and A330-941 (A330neo) Airplanes; Electronic Flight-Control System; Lateral-Directional and Longitudinal Stability, and Low-Energy Awareness

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 83, Issue 3 (January 4, 2018)

These special conditions are issued for the Airbus Model A330- 841 and A330-941 (A330neo) 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 low-energy awareness and directional stability with respect to electronic flight-control systems (EFCS). 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 83, Number 3 (Thursday, January 4, 2018)]
[Rules and Regulations]
[Pages 466-468]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2017-28453]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2017-0483; Special Conditions No. 25-708-SC]


Special Conditions: Airbus Model A330-841 and A330-941 (A330neo) 
Airplanes; Electronic Flight-Control System; Lateral-Directional and 
Longitudinal Stability, and Low-Energy Awareness

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for the Airbus Model A330-
841 and A330-941 (A330neo) 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 low-energy awareness and directional 
stability with respect to electronic flight-control systems (EFCS). 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 Airbus on January 4, 2018. Send your 
comments by February 20, 2018.

ADDRESSES: Send comments identified by docket number FAA-2017-0483 
using any of the following methods:
     Federal eRegulations Portal: Go to http://www.regulations.gov/and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov/, including any personal 
information the commenter provides. Using the search function of the 
docket website, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478).
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov/ at any time. Follow the online instructions 
for accessing the docket or go to Docket Operations in Room W12-140 of 
the West Building Ground Floor at 1200 New Jersey Avenue SE, 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Paul Giesman, FAA, Airplane and Flight 
Crew Interface, AIR-671, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, 1601 Lind Avenue 
SW, Renton, Washington 98057-3356; telephone 425-227-2790; facsimile 
425-227-1320.

SUPPLEMENTARY INFORMATION: The substance of these special conditions 
has been published in the Federal Register for public comment in 
several prior instances with no substantive comments received. The FAA 
therefore finds it unnecessary to delay the effective date and finds it 
unnecessary to delay the effective date and finds that good cause 
exists for making these special conditions effective upon publication 
in the Federal Register.

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data.
    We will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.

Background

    On January 20, 2015, Airbus applied for an amendment to Type 
Certificate No. A46NM to include the new Model A330-841 (A330-800neo) 
and A330-941 (A330-900neo) airplanes, collectively marketed as Model 
A330neo airplanes. These airplanes, which are derivatives of the Model 
A330-200 and A330-300 airplanes currently approved under Type 
Certificate No. A46NM, are wide-body, jet-engine airplanes with a 
maximum takeoff weight of 533,519 pounds and a passenger capacity of 
257 (A330-841); and a maximum takeoff weight of 535,503 pounds and a 
passenger capacity of 287 (A330-941).

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Airbus must show that the Model A330neo airplanes meet the 
applicable provisions of the regulations listed in Type Certificate No. 
A46NM, or the applicable regulations in effect on the date of 
application for the change, except for earlier amendments as agreed 
upon by the FAA.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for Model A330neo 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 novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, these special conditions would also apply to 
the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Airbus Model A330neo airplanes must comply with the 
fuel-vent and exhaust-emission requirements of 14 CFR part 34 and the 
noise-

[[Page 467]]

certification requirements of 14 CFR part 36.
    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.  21.101.

Novel or Unusual Design Features

    The Airbus Model A330neo airplanes will incorporate the following 
novel or unusual design features:
    Low-energy awareness and directional stability functions of the 
EFCS, which are not sufficiently addressed in Special Conditions (SC) 
No. 25-ANM-77, ``Airbus Industrie Model A330 Series Airplanes,'' 
Discussion section item 11, Flight Characteristics.

Discussion

    An initial review of the Model A330 and A340 airplanes' SC 25-ANM-
77, Discussion section item 11, and subsequent certifications of the 
Model A340-500/600, A380, and A350 airplanes, revealed that SC 25-ANM-
77, item 11, does not address low-energy awareness, nor does it provide 
similar detail as to the demonstration of directional stability, as has 
become the standard in later special conditions for Airbus airplanes.
    These special conditions, for the Model A330-841 and -941 
airplanes, replace the current item 11b and c in SC 25-ANM-77. In 
addition, these special conditions, in conjunction with the application 
of part 25, subpart B, at Amendment 25-108 for 1 g stall speeds; and 
Sec.  25.177(a) and (b) at Amendment 25-135; are intended to parallel 
the requirements provided in type certifications of Model A340-500 and 
-600, A380, and A350 airplanes.
    In the absence of positive lateral stability, the curve of lateral 
control-surface deflections against sideslip angle should be in a 
conventional sense and reasonably in harmony with rudder deflection 
during steady-heading sideslip maneuvers.
    Because conventional relationships between stick forces and 
control-surface displacements do not apply to the load-factor-command 
flight-control system on the Model A330-841 and -941 airplanes, 
longitudinal stability characteristics should be evaluated by assessing 
the airplane handling qualities during simulator and flight-test 
maneuvers appropriate to operation of the airplane. This may be 
accomplished by using the Handling Qualities Rating Method presented in 
Advisory Circular 25-7C, ``Flight Test Guide for Certification of 
Transport Category Airplanes,'' Appendix 5, or an acceptable 
alternative method proposed by the Airbus. Important considerations are 
as follows:
    1. Adequate speed control without excessive pilot workload,
    2. Acceptable high- and low-speed protection, and
    3. Provision for adequate cues to the pilot of significant speed 
excursions beyond VMO/MMO, and low-speed-
awareness flight conditions.
    The airplane should provide adequate awareness cues to the pilot of 
a low-energy (low-speed/low-thrust/low-height) state to ensure that the 
airplane retains sufficient energy to recover when flight-control laws 
provide neutral longitudinal stability significantly below the normal 
operating speeds. This may be accomplished as follows:
    1. Adequate low-speed/low-thrust cues at low altitude may be 
provided by a strong positive-static-stability force gradient (1 pound 
per 6 knots applied through the sidestick), or,
    2. The low-energy awareness may be provided by an appropriate 
warning with the following characteristics:
    a. It should be unique, unambiguous, and unmistakable.
    b. It should be active at appropriate altitudes and in appropriate 
configurations (i.e., at low altitude, in the approach and landing 
configurations).
    c. It should be sufficiently timely to allow recovery to a 
stabilized flight condition inside the normal flight envelope while 
maintaining the desired flight path, and without entering the flight 
controls angle-of-attack protection mode.
    d. It should not be triggered during normal operation, including 
operation in moderate turbulence for recommended maneuvers at 
recommended speeds.
    e. The system should not allow the pilot to cancel the warning, or 
the low-energy awareness function, other than by achieving a higher 
energy state.
    f. The various warnings should have an adequate hierarchy of alert 
so that the pilot is not confused and led to take inappropriate 
recovery action if multiple warnings occur at the same time.
    3. Global energy awareness and non-nuisance of low-energy cues 
should be evaluated by simulator and flight tests in the whole take-off 
and landing altitude range for which certification is requested. This 
would include all relevant combinations of weight, center-of-gravity 
position, configuration, airbrakes position, and available thrust, 
including reduced and derated take-off thrust operations and engine-
failure cases. A sufficient number of tests should be conducted, 
allowing the level of energy awareness and the effects of energy-
management errors to be assessed.
    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.

Applicability

    As discussed above, these special conditions are applicable to the 
Airbus Model A330-841 and A330-941 (A330neo) airplanes. Should Airbus 
apply at a later date for a change to the type certificate to include 
another model incorporating the same novel or unusual design feature, 
these special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on one model series of airplane. 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 Airbus Model A330-841 and A330-941 
(A330neo) airplanes.
    In lieu of the requirements of Sec. Sec.  25.171, 25.173, 25.175, 
and 25.177(c), the following special conditions apply:
    1. The airplane must be shown to have suitable static lateral, 
directional, and longitudinal stability in any condition normally 
encountered in service, including the effects of atmospheric 
disturbance. The showing of suitable static lateral, directional, and 
longitudinal stability must be based on the airplane handling 
qualities, including pilot workload and pilot compensation, for 
specific test procedures during the flight-test evaluations.
    2. The airplane must provide to the pilot adequate awareness of a 
low-energy (low-speed/low-thrust/low-height) state when fitted with 
flight-control laws presenting neutral longitudinal stability 
significantly below the normal operating speeds. ``Adequate awareness'' 
means that warning information must be provided

[[Page 468]]

to alert the flightcrew of unsafe operating conditions, and to enable 
them to take appropriate corrective action.
    3. In straight, steady sideslips over the range of sideslip angles 
appropriate to the operation of the airplane, but not less than those 
obtained with one-half of the available rudder-control movement (but 
not exceeding a rudder-control force of 180 pounds), rudder-control 
movements and forces must be substantially proportional to the angle of 
sideslip in a stable sense; and the factor of proportionality must lie 
between limits found necessary for safe operation. This requirement 
must be met for the configurations and speeds specified in Sec.  
25.177(a).

    Issued in Renton, Washington, on December 28, 2017.
Suzanne Masterson,
Acting Manager, Transport Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2017-28453 Filed 1-3-18; 8:45 am]
 BILLING CODE 4910-13-P