Airworthiness Directives; Boeing Model 737-100, -200, and -200C Series Airplanes

[Federal Register Volume 70, Number 122 (Monday, June 27, 2005)]
[Rules and Regulations]
[Pages 36829-36831]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-12503]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-289-AD; Amendment 39-14167; AD 2005-13-30]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, and -200C 
Series Airplanes

AGENCY: Federal Aviation Administration, Department of Transportation.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all Boeing Model 737-100, -200, and -200C series 
airplanes, that requires repetitive inspections to detect discrepancies 
of certain fuselage skin panels located just aft of the wheel well, and 
repair if necessary. The actions specified by this AD are intended to 
detect and correct fatigue cracking of the skin panels, which could 
cause rapid decompression of the airplane. This action is intended to 
address the identified unsafe condition.

DATES: Effective August 1, 2005.
    The incorporation by reference of a certain publication listed in 
the regulations is approved by the Director of the Federal Register as 
of August 1, 2005.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Suzanne Lucier, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6438; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to all Boeing Model 737-100, -200, 
and -200C series airplanes was published as a supplemental notice of 
proposed rulemaking (NPRM) in the Federal Register on April 1, 2005 (70 
FR 16761).

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comment that has been 
submitted on the proposed AD.

Support for the Proposed AD

    The commenter supports the proposed AD.

Conclusion

    We have carefully reviewed the available data, including the 
comment that has been submitted, and determined that air safety and the 
public interest require adopting the AD as proposed.

Interim Action

    This is considered to be interim action. The manufacturer has 
advised that it is developing an improved preventive modification 
intended to address the identified unsafe condition for unmodified skin 
areas. After this modification is developed, approved, and available, 
we may consider additional rulemaking.

Cost Impact

    There are about 1,000 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 390 airplanes of U.S. registry 
will be affected by this AD.
    The inspection will take about 47 to 88 work hours per airplane 
(depending on configuration), at an average labor rate of $65 per work 
hour. Based on these figures, we estimate the cost of the inspection to 
be $3,055 to $5,720 per airplane, per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

[[Page 36830]]

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 Impact

    The regulations adopted herein will 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness 
directive:

2005-13-30 Boeing: Amendment 39-14167. Docket 2002-NM-289-AD.

    Applicability: All Model 737-100, -200, and -200C series 
airplanes; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct fatigue cracking of the skin panels, which 
could cause rapid decompression of the airplane, accomplish the 
following:

Repetitive Inspections: Unmodified Skin Areas

    (a) For fuselage skin panel areas that have not been modified 
with stiffening angles: Before the airplane accumulates 16,000 total 
flight cycles, or within 4,500 flight cycles after the effective 
date of this AD, whichever occurs later, inspect the unmodified 
fuselage side skins just aft of the main wheelwell, and perform all 
follow-on actions, in accordance with Part I of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53-1065, Revision 2, 
dated April 19, 2001; except as provided by paragraph (g) of this 
AD. If no cracking, loose fasteners, disbonding, or damage is found: 
Repeat the inspection at the time specified in paragraph 1.E., 
Compliance, of the service bulletin, as applicable, except as 
provided by paragraph (d) of this AD.

Repetitive Inspections: Modified Skin Areas

    (b) For fuselage skin panel areas that have been modified with 
stiffening angles in accordance with Boeing Service Bulletin 737-53-
1065, dated January 4, 1985; Revision 1, dated October 12, 1989; or 
Revision 2, dated April 19, 2001: Before the airplane accumulates 
16,000 total flight cycles, or within 4,500 flight cycles after the 
effective date of this AD, whichever occurs later, inspect the 
modified areas as specified in accordance with Part I of Boeing 
Service Bulletin 737-53-1065, Revision 2, dated April 19, 2001. 
Repeat the inspection at the time specified in paragraph 1.E., of 
the service bulletin, as applicable, except as provided by paragraph 
(d) of this AD. If any cracks, loose fasteners, disbonding, or 
damage is found: Repair before further flight in accordance with the 
requirements of paragraph (d) of this AD.

Terminating Action for Inspections of Modified Skin Areas

    (c) For fuselage skin panel areas that have been modified with 
stiffening angles in accordance with Boeing Service Bulletin 737-53-
1065, dated January 4, 1985; Revision 1, dated October 12, 1989; or 
Revision 2, dated April 19, 2001: At the later of the times 
specified by paragraphs (c)(1) and (c)(2) of this AD, perform a 
subsurface eddy current or magneto optical imaging inspection to 
detect subsurface skin cracks along the edge of the bonded doubler, 
in accordance with Figure 10 of Boeing Service Bulletin 737-53-1065, 
Revision 2, dated April 19, 2001; except as provided by paragraph 
(g) of this AD. If any cracks are found, repair before further 
flight in accordance with paragraph (d) of this AD. Accomplishment 
of this inspection and all applicable corrective actions terminates 
the repetitive inspections required by paragraph (b) of this AD for 
the modified areas.
    (1) Inspect within 24,500, but not fewer than 20,000, flight 
cycles after the modification of the skin.
    (2) Inspect within 4,500 flight cycles after the effective date 
of this AD.

Repair: Modified and Unmodified Skin Areas

    (d) If any cracking is detected during any inspection required 
by this AD: Do the actions specified by paragraph (d)(1) or (d)(2) 
of this AD before further flight. Do the actions in accordance with 
Boeing Service Bulletin 737-53-1065, Revision 2, dated April 19, 
2001, except as required by paragraph (e) of this AD.
    (1) Do a time-limited repair (including a detailed inspection of 
the skin in the area of the repair to detect corrosion and doubler 
disbonding) in accordance with Part III of the Accomplishment 
Instructions of the service bulletin.
    (i) After the time-limited repair has been accomplished: At 
intervals not to exceed 3,000 flight cycles, perform an external 
general visual inspection of the repair to detect loose or missing 
fasteners, in accordance with Part III of the Accomplishment 
Instructions of the service bulletin, until the actions specified in 
paragraph (d)(1)(v) of this AD have been accomplished.
    (ii) Within 4,500 flight cycles after the time-limited repair 
has been accomplished: Perform an internal inspection of the repair 
to detect cracking or doubler disbonding using general visual and 
high-frequency eddy current methods, in accordance with Figure 11 of 
the service bulletin, unless the actions specified in paragraph 
(d)(1)(v) of this AD have been accomplished.
    (iii) If any cracking is found during any inspection required by 
paragraph (d)(1) of this AD: Repair before further flight in 
accordance with paragraph (e) of this AD. Another approved repair 
method is in Section 53-30-3, Figure 48, of the Boeing 737 
Structural Repair Manual (SRM).
    (iv) If any disbonding is found during any inspection required 
by paragraph (d)(1) of this AD: Repair before further flight in 
accordance with Part II of the service bulletin.
    (v) Within 10,000 flight cycles after accomplishment of the 
time-limited repair: Make the repair permanent in accordance with 
Part III of the Accomplishment Instructions of the service bulletin. 
Permanent repair of an area terminates the repetitive inspections 
specified in this AD for that repaired area only.
    (2) Do a permanent repair (including an inspection using 
external subsurface eddy

[[Page 36831]]

current or magneto optical imaging methods to detect cracks at the 
chem-milled step in each adjacent bay of the fuselage skin, a 
detailed inspection of the skin in the area of the repair for 
corrosion and doubler disbonding, and applicable corrective action) 
of the cracked area, in accordance with Part II of the 
Accomplishment Instructions of the service bulletin. Another 
approved repair method is in Section 53-30-3, Figure 48, of the 
Boeing 737 SRM. Permanent repair of an area terminates the 
repetitive inspections specified in this AD for that repaired area 
only.

Exceptions to Service Bulletin Procedures

    (e) During any inspection required by this AD, if any 
discrepancy (including cracking) is detected for which the service 
bulletin specifies to contact Boeing for appropriation action: 
Before further flight, repair according to a method approved by the 
Manager, Seattle Aircraft Certification Office (ACO), FAA; or 
according to data meeting the certification basis of the airplane 
approved by an Authorized Representative for the Boeing Delegation 
Option Authorization Organization who 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, and the approval must specifically refer to this AD.
    (f) Although Boeing Service Bulletin 737-53-1065, Revision 2, 
dated April 19, 2001, recommends that cracks found in Zone 2 be 
reported to Boeing, this AD does not require such a report.
    (g) For airplanes subject to the requirements of paragraphs (a) 
and (c) of this AD: Inspections are not required in areas that are 
spanned by an FAA-approved repair that has a minimum of 3 rows of 
fasteners above and below the chemical-milled step. If an external 
doubler covers the chemical-milled step, but does not span it by a 
minimum of 3 rows of fasteners above and below, one method of 
compliance with the inspection requirement of paragraphs (a) and (c) 
of this AD is to inspect all chemical-milled steps covered by the 
repair using internal nondestructive test (NDT) methods in 
accordance with Part 6, Subject 53-30-20, of the Boeing 737 NDT 
Manual. Follow-on and corrective actions must be done as specified 
in this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
ACO, FAA, is authorized to approve AMOCs for this AD.
    (2) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Delegation Option 
Authorization Organization who 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, and the approval must specifically refer to this AD.

Incorporation by Reference

    (i) Unless otherwise specified in this AD, the actions must be 
done in accordance with Boeing Service Bulletin 737-53-1065, 
Revision 2, dated April 19, 2001. This incorporation by reference 
was approved by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of this 
service information, contact Boeing Commercial Airplanes, P.O. Box 
3707, Seattle, Washington 98124-2207. To inspect copies of this 
service information, go to the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or to the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at the NARA, call (202) 741-6030, or 
go to http://www.archives.gov/ federal--register/code-- of--
federal--regulations/ ibr--locations.html.

Effective Date

    (j) This amendment becomes effective on August 1, 2005.

    Issued in Renton, Washington, on June 14, 2005.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-12503 Filed 6-24-05; 8:45 am]
BILLING CODE 4910-13-P

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