81 FR 72554 - Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 81, Issue 203 (October 20, 2016)

We propose to supersede Airworthiness Directive (AD) 2007-26- 04, which applies to certain Boeing Model 737-100, -200, -200C, -300, - 400, and -500 series airplanes. AD 2007-26-04 currently requires repetitive inspections for cracking around the heads of the fasteners on the forward fastener row of certain areas of a certain circumferential butt splice, and repair if necessary; and also requires a preventive modification, which eliminates the need for the repetitive inspections. Since we issued AD 2007-26-04, an evaluation by the design approval holder (DAH) indicating that the forward skin panel at a circumferential butt splice between certain stringers is subject to widespread fatigue damage (WFD). This proposed AD would remove the mandatory modification. It would add repetitive inspections of the skin for cracking at the aft fastener column and a one-time inspection for defects of the production countersunk rivets, and require corrective actions if necessary. It would also add an optional skin trim-out repair, which would terminate certain inspections. We are proposing this AD to prevent cracking of the station (STA) 259.5 circumferential butt splice, which could result in loss of structural integrity of the fuselage skin and possible loss of cabin pressure.

[Federal Register Volume 81, Number 203 (Thursday, October 20, 2016)]
[Proposed Rules]
[Pages 72554-72557]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2016-24262]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-9188; Directorate Identifier 2016-NM-102-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2007-26-
04, which applies to certain Boeing Model 737-100, -200, -200C, -300, -
400, and -500 series airplanes. AD 2007-26-04 currently requires 
repetitive inspections for cracking around the heads of the fasteners 
on the forward fastener row of certain areas of a certain 
circumferential butt splice, and repair if necessary; and also requires 
a preventive modification, which eliminates the need for the repetitive 
inspections. Since we issued AD 2007-26-04, an evaluation by the design 
approval holder (DAH) indicating that the forward skin panel at a 
circumferential butt splice between certain stringers is subject to 
widespread fatigue damage (WFD). This proposed AD would remove the 
mandatory modification. It would add repetitive inspections of the skin 
for cracking at the aft fastener column and a one-time inspection for 
defects of the production countersunk rivets, and require corrective 
actions if necessary. It would also add an optional skin trim-out 
repair, which would terminate certain inspections. We are proposing 
this AD to prevent cracking of the station (STA) 259.5 circumferential 
butt splice, which could result in loss of structural integrity of the 
fuselage skin and possible loss of cabin pressure.

DATES: We must receive comments on this proposed AD by December 5, 
2016.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Boeing 
Commercial Airplanes, Attention: Data & Services Management, P.O. Box 
3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-5000, 
extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. 
You may view this referenced service information at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information 
on the availability of this material at the FAA, call 425-227-1221. It 
is also available on the internet at http://www.regulations.gov by 
searching for and locating Docket No. FAA-2016-9188.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
9188; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Wade Sullivan, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6430; fax: 425-917-6590; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about

[[Page 72555]]

this proposed AD. Send your comments to an address listed under the 
ADDRESSES section. Include ``Docket No. FAA-2016-9188; Directorate 
Identifier 2016-NM-102-AD'' at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this proposed AD. We will consider 
all comments received by the closing date and may amend this proposed 
AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    Fatigue damage can occur locally, in small areas or structural 
design details, or globally, in widespread areas. Multiple-site damage 
is widespread damage that occurs in a large structural element such as 
a single rivet line of a lap splice joining two large skin panels. 
Widespread damage can also occur in multiple elements such as adjacent 
frames or stringers. Multiple-site damage and multiple-element damage 
cracks are typically too small initially to be reliably detected with 
normal inspection methods. Without intervention, these cracks will 
grow, and eventually compromise the structural integrity of the 
airplane. This condition is known as widespread fatigue damage. It is 
associated with general degradation of large areas of structure with 
similar structural details and stress levels. As an airplane ages, WFD 
will likely occur, and will certainly occur if the airplane is operated 
long enough without any intervention.
    The FAA's WFD final rule (75 FR 69746, November 15, 2010) became 
effective on January 14, 2011. The WFD rule requires certain actions to 
prevent structural failure due to WFD throughout the operational life 
of certain existing transport category airplanes and all of these 
airplanes that will be certificated in the future. For existing and 
future airplanes subject to the WFD rule, the rule requires that DAHs 
establish a limit of validity (LOV) of the engineering data that 
support the structural maintenance program. Operators affected by the 
WFD rule may not fly an airplane beyond its LOV, unless an extended LOV 
is approved.
    The WFD rule (75 FR 69746, November 15, 2010) does not require 
identifying and developing maintenance actions if the DAHs can show 
that such actions are not necessary to prevent WFD before the airplane 
reaches the LOV. Many LOVs, however, do depend on accomplishment of 
future maintenance actions. As stated in the WFD rule, any maintenance 
actions necessary to reach the LOV will be mandated by airworthiness 
directives through separate rulemaking actions.
    In the context of WFD, this action is necessary to enable DAHs to 
propose LOVs that allow operators the longest operational lives for 
their airplanes, and still ensure that WFD will not occur. This 
approach allows for an implementation strategy that provides 
flexibility to DAHs in determining the timing of service information 
development (with FAA approval), while providing operators with 
certainty regarding the LOV applicable to their airplanes.
    On December 10, 2007, we issued AD 2007-26-04, Amendment 39-15806 
(72 FR 71216, December 17, 2007) (``AD 2007-26-04''), for certain 
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. AD 2007-26-04 currently requires repetitive inspections for 
cracking around the heads of the fasteners on the forward fastener row 
of certain areas of the STA 259.5 circumferential butt splice, and 
repair if necessary; and also requires a preventive modification, which 
eliminates the need for the repetitive inspections. AD 2007-26-04 
resulted from a report of multiple cracks in the fuselage skin of a 
Model 737-200 airplane, at the forward fastener row of the STA 259.5 
circumferential butt splice between stringers 19 and 24. We issued AD 
2007-26-04 to prevent cracking of the STA 259.5 circumferential butt 
splice, which could result in loss of structural integrity of the 
fuselage skin and possible loss of cabin pressure.

Actions Since AD 2007-26-04 Was Issued

    Since we issued AD 2007-26-04, an evaluation by the DAH indicated 
that the forward skin panel at STA 259.5 circumferential butt splice 
between stringers 19L and 24L is subject to WFD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1267, Revision 1, 
dated March 8, 2016 (``ASB 737-53A1267 R1''). The service information 
describes procedures for detailed inspections and high frequency eddy 
current (HFEC) surface inspections of the skin around the fastener 
heads for any crack on the forward and aft fastener columns, left and 
right sides, at STA 259.5 circumferential butt splice; a detailed 
inspection for any defect of the production countersunk rivet heads on 
both forward and aft fastener columns, left and right sides, at STA 
259.5 circumferential butt splice; and corrective actions, including a 
skin trim-out repair and other repairs. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of these same type 
designs.

Proposed AD Requirements

    Although this proposed AD does not explicitly restate the 
requirements of AD 2007-26-04, this proposed AD would retain certain 
requirements of AD 2007-26-04. Those requirements are referenced in the 
service information identified previously, which, in turn, is 
referenced in this proposed AD.
    This proposed AD would also require accomplishing the actions 
specified in the service information described previously, except as 
discussed under ``Differences Between this Proposed AD and the Service 
Information.'' For information on the procedures and compliance times, 
see this service information at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2016-9188.
    The phrase ``corrective actions'' is used in this proposed AD. 
Corrective actions correct or address any condition found. Corrective 
actions in an AD could include, for example, repairs.

Explanation of Applicability

    Model 737 airplanes having line numbers 1 through 291 have a limit 
of validity (LOV) of 34,000 total flight cycles, and the actions 
proposed in this NPRM, as specified in ASB 737-53A1267 R1, would be 
required at a compliance time occurring after that LOV. Although 
operation of an airplane beyond its LOV is prohibited by 14 CFR 
121.1115 and 129.115, this proposed AD would include those airplanes in 
the applicability in the event the LOV is extended in the future.

Differences Between This Proposed AD and the Service Information

    ASB 737-53A1267 R1, specifies to contact the manufacturer for 
certain instructions, but this proposed AD

[[Page 72556]]

would require accomplishment of repair methods, modification 
deviations, and alteration deviations in one of the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom we have 
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 115 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost     Cost per product         operators
----------------------------------------------------------------------------------------------------------------
Inspections......................  28 work-hours x $85            $0   $2,380 per            $273,700 per
                                    per hour = $2,380                   inspection cycle.     inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the optional skin-trim-out repair specified in this 
proposed AD.
    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this proposed 
AD.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that the proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by removing Airworthiness Directive (AD) 
2007-26-04, Amendment 39-15806 (72 FR 71216, December 17, 2007), and 
adding the following new AD:

The Boeing Company: Docket No. FAA-2016-9188; Directorate Identifier 
2016-NM-102-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by December 5, 
2016.

(b) Affected Ads

    This AD replaces AD 2007-26-04, Amendment 39-15806 (72 FR 71216, 
December 17, 2007) (``AD 2007-26-04'').

(c) Applicability

    This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category, as identified in Boeing Alert Service Bulletin 737-
53A1267, Revision 1, dated March 8, 2016 (``ASB 737-53A1267 R1'').

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by an evaluation by the design approval 
holder (DAH) indicating that the forward skin panel at station (STA) 
259.5 circumferential butt splice between stringers 19L and 24L is 
subject to widespread fatigue damage (WFD). We are issuing this AD 
to prevent cracking of the STA 259.5 circumferential butt splice, 
which could result in loss of structural integrity of the fuselage 
skin and possible loss of cabin pressure.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Actions for Group 2 Airplanes

    For airplanes identified as Group 2 in ASB 737-53A1267 R1: 
Within 120 days after the effective date of this AD, inspect the 
airplane and do all applicable corrective actions using a method 
approved in accordance with the procedures specified in paragraph 
(k) of this AD.

(h) Inspections for Group 1 Airplanes

    For airplanes identified as Group 1 in ASB 737-53A1267 R1: 
Except as specified in paragraph (j)(1) of this AD, at the 
applicable time specified in paragraph 1.E. ``Compliance'' of ASB 
737-53A1267 R1, do the applicable actions specified in paragraphs 
(h)(1) and (h)(2) of this AD; and do all applicable corrective 
actions; in accordance with the Accomplishment Instructions of ASB 
737-53A1267 R1, except as specified in paragraph (j)(2) of this AD. 
Do all applicable corrective actions before further flight. Repeat 
the applicable inspections specified in paragraph (h)(1) of this AD 
thereafter at the applicable intervals specified paragraph 1.E., 
``Compliance,'' of ASB 737-53A1267 R1, except as provided by 
paragraph (i) of this AD.
    (1) Do detailed inspections and high frequency eddy current 
(HFEC) surface inspections of the skin around the fastener heads for 
any crack on the forward and aft fastener columns, left and right 
sides, at STA 259.5 circumferential butt splice, in accordance with 
Parts 1, 2, 6, 7, 8, and 9 of

[[Page 72557]]

the Accomplishment Instructions of ASB 737-53A1267 R1, as 
applicable.
    (2) Do a one-time detailed inspection for any defect of the 
production countersunk rivet heads on both forward and aft fastener 
columns, left and right sides, at STA 259.5 circumferential butt 
splice, in accordance with Part 3 of the Accomplishment Instructions 
of ASB 737-53A1267 R1.

(i) Optional Terminating Repairs

    (1) For airplanes identified as Group 1, Configuration 1 in ASB 
737-53A1267 R1: Doing the skin trim-out repair specified in Part 5 
of the Accomplishment Instructions of ASB 737-53A1267 R1 terminates 
the repetitive inspections required by paragraph (h) of this AD that 
are specified in Part 1 of the Accomplishment Instructions of ASB 
737-53A1267 R1 only; all other repetitive inspections required by 
paragraph (h) of this AD must be done, except as provided by 
paragraph (i)(2) of this AD.
    (2) For airplanes identified as Group 1, Configuration 1 in ASB 
737-53A1267 R1: Doing the skin repair specified in Part 4 of the 
Accomplishment Instructions of ASB 737-53A1267 R1, terminates the 
repetitive inspections required by paragraph (h) of this AD that are 
specified in Part 1 and Part 2 of the Accomplishment Instructions of 
ASB 737-53A1267 R1 for the repaired area only; all other repetitive 
inspections required by paragraph (h) of this AD must be done, 
except as provided by paragraph (i)(1) of this AD.

(j) Exceptions to Service Information

    (1) Where paragraph 1.E., ``Compliance,'' of ASB 737-53A1267 R1, 
specifies a compliance time ``after the Revision 1 date of this 
service bulletin,'' this AD requires compliance within the specified 
compliance time after the effective date of this AD.
    (2) Although ASB 737-53A1267 R1, specifies to contact Boeing for 
appropriate action, and specifies that action as ``RC'' (Required 
for Compliance), this AD requires repair before further flight using 
a method approved in accordance with the procedures specified in 
paragraph (k) of this AD.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), FAA, has the authority to approve AMOCs for this AD, if 
requested using the procedures found in 14 CFR 39.19. In accordance 
with 14 CFR 39.19, send your request to your principal inspector or 
local Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in paragraph (l)(1) of this AD. 
Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by the Boeing Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles ACO, to make those findings. To be approved, 
the repair method, modification deviation, or alteration deviation 
must meet the certification basis of the airplane and the approval 
must specifically refer to this AD.
    (4) AMOCs approved previously for AD 2007-26-04 are approved as 
AMOCs for the corresponding provisions of this AD.
    (5) Except as required by paragraph (j)(2) of this AD: For 
service information that contains steps that are labeled as RC, the 
provisions of paragraphs (k)(5)(i) and (k)(5)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or sub-step is labeled ``RC Exempt,'' then 
the RC requirement is removed from that step or sub-step. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(l) Related Information

    (1) For more information about this AD, contact Wade Sullivan, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office (ACO), 1601 Lind Avenue SW., Renton, WA 98057-
3356; phone: 425-917-6430; fax: 425-917-6590; email: 
[email protected].
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-66-5680; Internet https://www.myboeingfleet.com. You may view this referenced service 
information at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue SW., Renton, WA. For information on the availability of this 
material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on September 30, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-24262 Filed 10-19-16; 8:45 am]
 BILLING CODE 4910-13-P