[Federal Register Volume 75, Number 96 (Wednesday, May 19, 2010)]
[Proposed Rules]
[Pages 27969-27972]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-11905]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0481; Directorate Identifier 2009-NM-192-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-100 and -
200 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Model 737-100 and -200 series airplanes. This proposed AD would 
require repetitive inspections for cracking and damaged fasteners of 
certain fuselage frames and stub beams, and corrective actions if 
necessary. For certain airplanes, this proposed AD would also require 
repetitive inspections for cracking of the inboard chord fastener hole 
of the frame at body station 639, stringer S-16, and corrective actions 
if necessary. For certain airplanes, this proposed AD would also 
require an inspection to determine the edge margin of the lower chord. 
For airplanes with a certain short edge margin, this proposed AD 
requires repetitive inspections for cracking, and corrective actions if 
necessary; replacing the lower chord terminates the repetitive 
inspections. This proposed AD requires an eventual preventive 
modification. For certain airplanes, doing the modification or a repair 
would terminate the repetitive inspections for the repaired or modified 
frame only. For airplanes on which the modification or repair is done 
at certain body stations, this proposed AD would require repetitive 
inspections for cracking of certain frame webs and inner and outer 
chords, and corrective actions if necessary. For certain other 
airplanes, this proposed AD requires a modification which includes 
reinforcing the body frame inner chords, replacing the stub beam upper 
chords and attach angles, and reinforcing the stub beam web. This 
proposed AD results from reports of fatigue cracks at certain frame 
sections, in addition to stub beam cracking, caused by high flight 
cycle stresses from both pressurization and maneuver load. We are 
proposing this AD to detect and correct fatigue cracking of certain 
fuselage frames and stub beams, and possible severed frames, which 
could result in reduced structural integrity of the frames. This 
reduced structural integrity can increase loading in the fuselage skin, 
which will accelerate skin crack growth and result in rapid 
decompression of the fuselage.

DATES: We must receive comments on this proposed AD by July 6, 2010.

ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1, fax 206-766-5680; e-mail [email protected]; 
Internet  https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; 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 (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6447; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2010-0481; 
Directorate Identifier 2009-NM-192-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

    We have received reports of fatigue cracks found at certain frame 
sections, in addition to stub beam cracking, caused by high flight 
cycle stresses from both pressurization and maneuver load. Numerous 
cracks were found in the shear ties, webs, and inboard and outboard 
chords of the overwing body frames and stub beams between body stations 
559 and 639. Cracks were also found in the webs, attach angles, and the 
upper and lower chords of the stub beams. There were reports of sheared 
fasteners in the overwing body frames and stub beams in the same 
location.
    Fatigue cracking of certain fuselage frames and stub beams, if not 
detected and corrected, and possible severed frames, could result in 
reduced structural integrity of the frames. This reduced structural 
integrity can increase loading in the fuselage skin, which will 
accelerate skin crack growth and result in rapid decompression of the 
fuselage.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 737-53-1061, Revision 4, 
including Addendum, dated July 16, 1992. For airplanes on which a 
repair (Part III) or preventive modification (Part II) has not been 
done, the service bulletin describes procedures for

[[Page 27970]]

repetitive detailed inspections for cracks and damaged fasteners in the 
circumferential frame and the stub beam at body stations 559, 578, 597, 
616, and 639, and corrective actions if necessary. For Group 1-3 
airplanes, the service bulletin describes procedures for repetitive 
eddy current inspections for cracking of the inboard chord fastener 
hole of the frame at body station 639, stringer S-16, and corrective 
actions if necessary. For airplanes on which certain stub beam lower 
chords were installed, the service bulletin describes procedures for an 
inspection to determine if a short edge margin exists in the lower 
chord and, for airplanes with a certain short edge margin, repetitive 
inspections for cracking and corrective actions if necessary. For 
airplanes on which either circumferential frame at body station 597 was 
changed as given in Boeing Service Bulletin 737-53-1061, Revision 1, 
dated December 16, 1983; Revision 2, dated April 18, 1986; or Revision 
3, dated June 15, 1989; the service bulletin describes procedures for 
repetitive detailed inspections for cracking of the frame.
    This service bulletin also describes a preventive modification, 
which would eliminate the need for the repetitive inspections. For 
airplanes on which the modification or repair is done at body stations 
616 and 639, the service bulletin describes procedures for repetitive 
detailed inspections for cracking of the body station 616 and 639 frame 
webs and inner and outer chords, near stringer S-16, and corrective 
actions if necessary.
    The corrective actions include doing a repair for any cracking and 
damaged fasteners that are within the limits specified, replacing a 
cracked component by installation of a preventive modification if the 
cracks are outside the limits, and contacting Boeing for instructions 
if cracks or damaged fasteners cannot be repaired in accordance with 
the specified procedures or if the upper chord was replaced at a 
certain location.
    For Group 1-3 airplanes, the service bulletin describes procedures 
for a modification, which includes reinforcing the body frame inner 
chords, replacing the stub beam upper chords and attach angles, and 
reinforcing the stub beam web at body stations 597, 616, and 639.

Related Rulemaking

    We are in the process of issuing an AD that refers to Boeing Alert 
Service Bulletin 737-53A1254, Revision 1, dated July 9, 2009, and is 
related to this proposed AD. That service information applies to Model 
737-200, -300, -400, and -500 series airplanes. During review of that 
service information it was determined that the same unsafe condition 
exists on earlier Boeing Model 737-100 and -200 series airplanes 
identified in Boeing Service Bulletin 737-53-1061, Revision 4, dated 
July 16, 1992, referred to in this proposed AD as the appropriate 
source of service information for accomplishing the actions.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed AD and the Service Information.''

Differences Between the Proposed AD and the Service Information

    Although the Accomplishment Instructions of Boeing Service Bulletin 
737-53-1061, Revision 4, dated July 16, 1992, include a modification 
for Group 4 airplanes (Model 737-200C airplanes), the applicability of 
this proposed AD does not include those airplanes. This proposed AD is 
applicable to passenger airplanes only.
    The service bulletin also specifies to contact the manufacturer for 
instructions on repairing cracks, but this proposed AD would require 
repairing cracks in one of the following ways:
     Using 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 Delegation Authorization (ODA) that we have 
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD would affect 45 airplanes of U.S. 
registry.
    We estimate that it would take about 4 work-hours per product to 
comply with the proposed inspections. The average labor rate is $85 per 
work-hour. Based on these figures, we estimate the cost of this 
proposed inspection to the U.S. operators to be $15,300, or $340 per 
product, per inspection cycle.
    We estimate that it would take about 288 work-hours per product to 
comply with the proposed modification (for Group 1-3 airplanes). The 
average labor rate is $85 per work-hour. Required parts would cost 
about $58,742 per product. Based on these figures, we estimate the cost 
of this proposed modification to the U.S. operators to be $83,222 per 
product.

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 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 this 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), and
    3. 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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:

[[Page 27971]]

PART 39--AIRWORTHINESS DIRECTIVES

    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]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0481; Directorate Identifier 
2009-NM-192-AD.

Comments Due Date

    (a) We must receive comments by July 6, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-100 and -200 
series airplanes, certificated in any category; line numbers 1 
through 848 inclusive.

Subject

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

Unsafe Condition

    (e) This AD results from reports of fatigue cracks at certain 
frame sections, in addition to stub beam cracking, caused by high 
flight cycle stresses from both pressurization and maneuver load. 
The Federal Aviation Administration is issuing this AD to detect and 
correct fatigue cracking of certain fuselage frames and stub beams, 
and possible severed frames, which could result in reduced 
structural integrity of the frames. This reduced structural 
integrity can increase loading in the fuselage skin, which will 
accelerate skin crack growth and result in rapid decompression of 
the fuselage.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Inspections

    (g) For airplanes on which a repair (Part III of the 
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061) 
or preventive modification (Part II of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53-1061) has not been 
done in accordance with Boeing Service Bulletin 737-53-1061 as of 
the effective date of this AD: Before the accumulation of 15,000 
total flight cycles or within 3,000 flight cycles after the 
effective date of this AD, whichever occurs later, do the 
inspections required by paragraphs (g)(1) and (g)(2) of this AD, in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 737-53-1061, Revision 4, dated July 16, 1992. Repeat the 
inspection at the time specified, until the terminating action 
required by paragraph (l) of this AD is done.
    (1) Do a detailed inspection (Part I of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53-1061) for cracks and 
damaged fasteners of the fuselage frames and stub beams. If no crack 
or damaged fastener is found, repeat the inspection thereafter at 
intervals not to exceed 4,500 flight cycles.
    (2) Do an eddy current inspection (Part IV of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53-1061) for cracking of 
the inboard chord fastener hole of the frame at body station 639, 
stringer S-16. If no crack is found, repeat the inspection 
thereafter at intervals not to exceed 15,000 flight cycles.

    Note 1:  Access and restoration instructions, as detailed in the 
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061, 
Revision 4, dated July 16, 1992, are not required by this AD. 
Operators may do those actions in accordance with their maintenance 
practices.

    (h) For airplanes on which the body station 597 frame was 
changed as of the effective date of this AD, in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061, 
dated May 28, 1982; Revision 1, dated December 16, 1983; Revision 2, 
dated April 18, 1986; or Revision 3, dated June 15, 1989: Within 
3,000 flight cycles after the effective date of this AD, do a 
detailed inspection for cracking of the frame, in accordance with 
the Accomplishment Instructions of Boeing Service Bulletin 737-53-
1061, Revision 4, dated July 16, 1992. Repeat the detailed 
inspection thereafter at intervals not to exceed 4,500 flight 
cycles. Installation of new radius fillers in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061, 
Revision 4, dated July 16, 1992, terminates the inspections required 
by this paragraph.
    (i) For airplanes on which a stub beam lower chord with \1/4\-
inch diameter fasteners at body station 597 is installed as of the 
effective date of this AD, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 737-53-1061, Revision 1, 
dated December 16, 1983; Revision 2, dated April 18, 1986; or 
Revision 3, dated June 15, 1989: Within 3,000 flight cycles after 
the effective date of this AD, do a detailed inspection for short 
edge margins. If the short edge margin is determined to be less than 
1.5D (diameter), before further flight, do a detailed inspection for 
cracking of the stub beam lower chords, in accordance with Boeing 
Service Bulletin 737-53-1061, Revision 4, dated July 16, 1992. 
Repeat the detailed inspection thereafter at intervals not to exceed 
4,500 flight cycles, if the edge margin is less than 1.5D. If the 
edge margin is greater than or equal to 1.5D, no further action is 
required by this paragraph. Replacing the lower chord in accordance 
with Boeing Service Bulletin 737-53-1061, Revision 4, dated July 16, 
1992, terminates the repetitive inspections specified in this 
paragraph.

Corrective Actions

    (j) Except as required by paragraph (k) of this AD, if any crack 
or damaged fastener is found during any inspection required by this 
AD, before further flight, repair if cracking and damaged fasteners 
are within the specified limits, or do a preventive modification if 
cracking or damaged fasteners are outside the specified limits, in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 737-53-1061, Revision 4, dated July 16, 1992.

Exception to Service Information

    (k) Where Boeing Service Bulletin 737-53-1061, Revision 4, dated 
July 16, 1992, specifies to contact Boeing for repair instructions: 
Before further flight, repair using a method approved in accordance 
with the procedures specified in paragraph (n) of this AD.

Terminating Action (Preventive Modification) for Certain Inspections

    (l) Before the accumulation of 75,000 total flight cycles: Do 
the preventive modification in accordance with Part II, or repair in 
accordance with Part III, of the Accomplishment Instructions of 
Boeing Service Bulletin 737-53-1061, Revision 4, dated July 16, 
1992. The modification or repair terminates the repetitive 
inspection requirements of this AD for the repaired or modified 
frame only, except as required by paragraph (m) of this AD.

Post-Modification or Repair Inspections

    (m) For airplanes on which a repair or modification at body 
station 616 or 639 is done: Within 24,000 flight cycles after doing 
the repair or modification, or within 3,000 flight cycles after the 
effective date of this AD, whichever occurs later, do a detailed 
inspection for cracking of the BS 616 and 639 frame webs, inner 
chord, and outer chord near stringer S-16, in accordance with Boeing 
Service Bulletin 737-53-1061, Revision 4, dated July 16, 1992.
    (1) If no cracking is found, repeat the inspection thereafter at 
intervals not to exceed 4,500 flight cycles.
    (2) If any cracking is found, before further flight, repair the 
cracking using a method approved in accordance with the procedures 
specified in paragraph (n) of this AD.

Alternative Methods of Compliance (AMOCs)

    (n)(1) The Manager, Seattle 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. Send information to 
ATTN: Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, 
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6447; fax (425) 
917-6590. Or, e-mail information to [email protected].
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by the

[[Page 27972]]

Boeing Commercial Airplanes Organization Delegation Authorization 
(ODA) that has been authorized by the Manager, Seattle ACO, to make 
those findings. For a repair method to be approved, the repair must 
meet the certification basis of the airplane.

    Issued in Renton, Washington, on May 5, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-11905 Filed 5-18-10; 8:45 am]
BILLING CODE 4910-13-P