AD 2012-23-04

[Federal Register Volume 77, Number 225 (Wednesday, November 21, 2012)]
[Rules and Regulations]
[Pages 69747-69754]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2012-27636]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0722; Directorate Identifier 2010-NM-262-AD; 
Amendment 39-17260; AD 2012-23-04]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are superseding an existing airworthiness directive (AD) 
for certain The Boeing Company Model 737-100 and -200 series airplanes. 
The existing AD currently requires various inspections for cracks in 
the outboard chord of the frame at body station (BS) 727 and in the 
outboard chord of stringer (S) 18A, and repair or replacement of 
cracked parts. This new AD adds airplanes to the applicability 
statement in the existing AD and adds inspections for cracks in the BS 
727 frame outboard chords and the radius of the auxiliary chord, for 
certain airplanes. This new AD also removes the inspections of the 
outboard chord of S-18A required by the existing AD. This AD was 
prompted by several reports of fatigue cracking in the frame outboard 
chord at BS 727 and in the radius of the auxiliary chord on airplanes 
that were not affected by the existing AD. We are issuing this AD to 
detect and correct fatigue cracking of the outboard and auxiliary 
chords, which could result in reduced structural integrity of the 
outboard chord and consequent rapid decompression of the airplane.

DATES: This AD is effective December 26, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of December 26, 
2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain other publications listed in this AD as of August 
18, 1995 (60 FR 36981, July 19, 1995).

ADDRESSES: For service information identified in this 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; Internet <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. 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 <a href="http://www.regulations.gov">http://www.regulations.gov</a>; 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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, Washington 98057-3356; phone (425) 917-
6450; fax (425) 917-6590; email <a href="/cdn-cgi/l/email-protection#8feee3eee1a1ffe0e7e3cfe9eeeea1e8e0f9"><span class="__cf_email__" data-cfemail="dcbdb0bdb2f2acb3b4b09cbabdbdf2bbb3aa">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 95-12-17, Amendment 39-9268 (60 FR 36981, July 
19, 1995). That AD applies to the specified products. The NPRM 
published in the Federal Register on August 5, 2011 (76 FR 47522). That 
NPRM proposed to continue to require various inspections for cracks in 
the outboard chord of the frame at BS 727, and repair or replacement of 
cracked parts. That NPRM also proposed to add airplanes to the 
applicability statement in the existing AD and add inspections for 
cracks in the BS 727 frame outboard chords and the radius of the 
auxiliary chord, for certain airplanes. That NPRM also proposed to 
remove the inspections of the outboard chord of S-18A required by the 
existing AD.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 47522, August 5, 2011) and the FAA's response to each comment.

Support for NPRM (76 FR 47522, August 5, 2011)

    Europe Airpost has no objection to the NRPM (76 FR 47522, August 5, 
2011), and noted that it has already implemented the procedures in 
Boeing

[[Page 69748]]

Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, 
into its maintenance program.

Request To Remove ``Total'' From Compliance Time

    Southwest Airlines (SWA) asked that paragraph (o) of the NPRM (76 
FR 47522, August 5, 2011), which specifies the compliance time as 
``Before the accumulation of 50,000 total flight cycles, but fewer than 
or equal to 60,000 total flight cycles, after accomplishing the 
modification of the outboard chord of the frame * * *'' be changed to 
delete the word ``total.'' SWA states that this would eliminate any 
confusion as to whether the subject inspection is to be done between 
50,000 and 60,000 total airplane flight cycles, or between 50,000 and 
60,000 flight cycles after the modification installation.
    We agree with the commenter. The intent of paragraph (o) of this AD 
is to do the inspection between 50,000 and 60,000 flight cycles after 
accomplishing the modification. We have changed paragraph (o) of this 
AD accordingly. In addition, for clarification, we have removed 
``total'' from paragraphs (g), (h)(1), (h)(2), (h)(3), and (h)(4) of 
this AD.

Request To Clarify Certain Compliance Times

    Boeing asked that we clarify the compliance time for the inspection 
specified in paragraph (i)(1) of the NPRM (76 FR 47522, August 5, 
2011). Boeing stated that paragraph (c)(1) of AD 95-12-17, Amendment 
39-9268 (60 FR 36981, July 19, 1995), states ``Inspect prior to the 
accumulation of 4,500 flight cycles after the effective date of this 
AD.'' The new language in paragraph (i)(1) of the NPRM states ``Inspect 
prior within 4,500 flight cycles after August 18, 1995.'' Boeing noted 
that this looks like a typographical error.
    We find that there is a terminology error in paragraph (c)(1) of 
the existing AD 95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 
1995), and in paragraph (i)(1) of this AD. We have corrected that 
paragraph to read: ``Inspect within 4,500 flight cycles after August 
18, 1995 * * *.'' We have also corrected similar terminology in 
paragraphs (i)(2), (i)(3), and (i)(4) of this AD.
    Boeing also asked that we clarify the compliance time specified in 
paragraph (n) of the NPRM (76 FR 47522, August 5, 2011). Boeing stated 
that Table 3 of Boeing Alert Service Bulletin 737-53A1166, Revision 2, 
dated May 25, 2006, specifies ``total airplane flight cycles after 
replacement'' and paragraph (g) of the NPRM addresses previously 
replaced frame upper outboard chords for comparison. Boeing added that 
paragraphs (n)(1)(i) and (n)(1)(ii) of the NPRM identify the threshold 
for a replaced frame upper outboard chord in terms of ``total flight 
cycles,'' but Table 3 of that service bulletin identifies the threshold 
based on cycles ``after chord replacement.''
    We agree that the compliance time specified in paragraphs (n)(1)(i) 
and (n)(1)(ii) of this AD should be expressed in terms of flight cycles 
after replacement of the outboard chords, as identified in Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, not total 
flight cycles on the airplane. We have clarified the compliance time in 
paragraphs (n)(1)(i) and (n)(1)(ii) of this AD accordingly.

Request To Include Repair Instructions

    Boeing asked that we include repair instructions in paragraph (o) 
of the NPRM (76 FR 47522, August 5, 2011) for crack findings during the 
open-hole eddy current inspection. Boeing notes that no repair 
instructions are provided. Boeing suggests the following be added for 
the repair: ``Except as required by paragraph (p) of this AD, if any 
crack is found during the inspection required by this paragraph, before 
further flight, repair in accordance with Part 3 or Part 4, as 
applicable, of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1166, Revision 2, dated May 25, 2006.''
    We agree with the commenter for the reason provided. In paragraph 
(o) of the NPRM (76 FR 47522, August 5, 2011), we inadvertently omitted 
the repair language specified in paragraphs (l) through (n) of the NPRM 
from paragraph (o) of the NPRM. In the preamble of the NPRM in the 
``Relevant Service Information'' section, we described additional 
inspections, and repair or replacement if necessary. Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, contains 
repair instructions in Part 3 and Part 4. Therefore, we have added the 
text ``* * * repair in accordance with Part 3 or Part 4 * * *.'' to 
paragraph (o) of this AD. Paragraph (p) of this AD already contains a 
reference to paragraph (o) of this AD for the exception to the repair 
procedure.

Request To Clarify Repair Instructions

    Boeing asked that we clarify the repair instructions specified in 
paragraph (l) of the NPRM (76 FR 47522, August 5, 2011) for cracks 
found in the auxiliary chord. Boeing stated that paragraph (l) of the 
NPRM specifies ``If any crack is found, before further flight, repair 
in accordance with the requirements in paragraph (p) of this AD.'' 
Boeing noted that paragraph (p) of the NPRM directs the reader to 
paragraph (s) of the NPRM for an alternative method of compliance 
(AMOC) if Part 3 or Part 4 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, 
cannot be accomplished. Boeing added that neither Part 3 nor Part 4 
provide repair instructions for the auxiliary chord. Boeing added that 
paragraph (n) of the NPRM provides clear instructions for accomplishing 
the crack repair.
    We acknowledge the commenter's concerns. The inspection identified 
in paragraph (l) of this AD is required to detect cracks in the 
auxiliary chord radius of the frame at BS 727. The inspection 
identified in paragraph (n) of this AD is required to detect cracks in 
the forward flange of the outboard chord at BS 727. The repair 
instructions for those areas are specified in different parts of the 
Accomplishment Instructions of the service information; therefore, the 
repair identified in paragraph (n) of this AD should not refer to the 
same repair instructions as those identified in paragraph (l) of this 
AD. Since Parts 3 and 4 of the Accomplishment Instructions of the 
service information do not provide repair instructions for the 
auxiliary chord, we have clarified the repair instructions in paragraph 
(l) of this AD by changing the reference from paragraph (p) to 
paragraph (s) of this AD. In addition, we have removed the reference to 
paragraph (l) from paragraph (p) of this AD for further clarification.

Request To Clarify When Time-Limited Repairs Are Required for Certain 
Airplanes

    Boeing asked that we clarify when time-limited repairs, as 
specified in paragraph (q) of the NPRM (76 FR 47522, August 5, 2011), 
installed in accordance with Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006, must be replaced. Boeing stated that 
paragraph (q) of the NPRM identifies replacement for time-limited 
repairs installed in accordance with Boeing Alert Service Bulletin 737-
53A1166, dated June 30, 1994; or Boeing Service Bulletin 737-53A1166, 
Revision 1, dated May 25, 1995; but does not provide a compliance time 
for time-limited repairs installed in accordance with Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006. Boeing 
added that the compliance time specified in Table 6 of Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, is not to 
exceed

[[Page 69749]]

4,500 flight cycles from the time of the installation.
    We agree to clarify paragraph (q) of this AD. In the NPRM (76 FR 
47522, August 5, 2011), we did not refer to airplanes identified in 
Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 
2006, as airplanes affected by paragraph (q) of this AD. However, Step 
3.b. of ``Part 4--STA 727 Frame Outboard Chord Time-Limited Repair'' of 
the Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1166, Revision 2, dated May 25, 2006, specifies doing the 
replacement of the time-limited repair at the time specified in 
paragraph 1.E., ``Compliance,'' of that service bulletin revision 
(i.e., 4,500 flight cycles after the time-limited replacement). 
Therefore, we have determined that Boeing Alert Service Bulletin 737-
53A1166, Revision 2, dated May 25, 2006, should be added to paragraph 
(q) of this AD as a reference for airplanes affected by that paragraph.

Request To Clarify Affected Airplanes

    Boeing asked that the affected airplanes be added to paragraph (j) 
of the NPRM (76 FR 47522, August 5, 2011). Boeing stated that paragraph 
(h) of the NPRM identifies the affected airplanes, and that paragraph 
(j) of the NPRM has similar requirements and should match paragraph (h) 
of the NPRM.
    We agree that the affected airplane models should be added to 
paragraph (j) of this AD for clarification and consistency. We have 
changed that paragraph to include the affected airplane models.
    Boeing also asked that we clarify paragraphs (g), (h), (i), and (j) 
of the NPRM (76 FR 47522, August 5, 2011), by specifying that the 
airplanes affected by those paragraphs, which are restated from AD 95-
12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), are only those 
Model 737-100 and -200 series airplanes having line numbers 1 through 
999 inclusive. Boeing stated that the NPRM requirements do not 
differentiate for Model 737-200 series airplanes having line numbers 
beyond 999 and do not identify Model 737-200C series airplanes.
    We agree that the restated requirements specified in this AD only 
affect Model 737 airplanes having line numbers 1 through 999 inclusive. 
We have added that clarification to paragraphs (g), (h), (i), and (j) 
of this AD.

Request To Clarify Affected Airplanes Relative to Supplemental 
Structural Inspection Document (SSID) Inspections

    Boeing asked that we provide clarification of certain affected 
airplanes in paragraph (s)(5) of the NPRM (76 FR 47522, August 5, 
2011). Boeing stated that AD 2008-08-23, Amendment 39-15477 (73 FR 
21237, April 21, 2008), only applies to Model 737-200C series 
airplanes. Boeing added that Boeing SSID D6-37089, Revision E, dated 
May 1, 2007, applies to Model 737-100, -200, and -200C series 
airplanes. Boeing also asked that we clarify that AD 2008-09-13, 
Amendment 39-15494 (73 FR 24164, May 2, 2008), is only applicable to 
Model 737-300, -400, and -500 series airplanes. Boeing stated that 
paragraph (s)(5) of the NPRM refers to Boeing 737-400/500/600 SSID D6-
82669, dated May 1, 2007, but noted that Model 737-600 is a next 
generation (NG) airplane, not a 737 ``Classic'' airplane.
    Boeing also asked that the structurally significant item (SSI) F-29 
SSID inspections (which describe visual and eddy current inspections of 
the BS 727 bulkhead outer chord) in paragraph (s)(5) of the NPRM (76 FR 
47522, August 5, 2011) refer to Appendix A of Boeing Alert Service 
Bulletin 737-53A1166, Revision 2, dated May 25, 2006, for consistency. 
Boeing states that currently paragraph 1.F. of Boeing Alert Service 
Bulletin 737-53A1166, Revision 2, dated May 25, 2006, refers to table 1 
of Appendix A.
    We agree that some clarifications are necessary for the reasons 
provided by the commenter. Therefore, we have included the appropriate 
information in paragraph (s)(5) of this AD. We clarified that AD 2008-
08-23, Amendment 39-15477 (73 FR 21237, April 21, 2008), applies to 
Model 737-200C series airplanes. We changed the reference to ``Boeing 
737-400/500/600 SSID'' to the correct reference, which is ``Boeing 737-
300/400/500 SSID.'' In addition, we added a reference to Appendix A, 
Table 1, of Boeing Alert Service Bulletin 737-53A1166, Revision 2, 
dated May 25, 2006, for the SSI F-29 SSID inspections.

Request To Clarify Actions Required for Affected Airplanes

    Boeing asked that we clarify actions to be taken for airplanes 
affected by both the restated requirements and the new requirements of 
the NPRM (76 FR 47522, August 5, 2011). Boeing stated that paragraphs 
(g) through (j) of the NPRM are identified as applicable to Model 737-
100 and -200 series airplanes; and paragraphs (m) and (n) of the NPRM 
are applicable to airplanes identified in Tables 2 and 3, respectively, 
of paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-53A1166, Revision 2, dated May 25, 2006. Boeing noted that Model 
737-100 and -200 series airplanes (having line numbers 1 through 999 
inclusive) are identified in Groups 1, 2, and 3 of that service 
bulletin; both tables 2 and 3 of that service bulletin identify Groups 
1, 2, and 3. Boeing added that Model 737-100 and -200 series airplanes 
have threshold and repetitive inspection requirements from both the 
restated and the new requirements of the NPRM.
    We agree with the commenter that some clarification is necessary. 
We have changed paragraphs (m) and (n) of this AD (new requirements) to 
include the statement that accomplishing the new inspections in each 
paragraph ends the corresponding retained inspections in paragraphs (g) 
through (j) of this AD.

Request To Clarify Revised Paragraph Identifiers

    Boeing asked that we clarify the ``Revised paragraph identifiers'' 
table in the preamble of the NPRM (76 FR 47522, August 5, 2011). Boeing 
states that paragraph (g) of AD 95-12-17, Amendment 39-9268 (60 FR 
36981, July 19, 1995), corresponds to the new paragraph (r) of the NPRM 
(optional terminating action), not the new paragraph (l) of the NPRM, 
which is related to auxiliary chord inspections. Boeing also asked that 
we clarify that the terminating action specified in paragraphs (h) and 
(j) of the NPRM refers to the terminating action in paragraph (r) of 
this AD instead of paragraph (l) of this AD.
    We agree that there is an error in the ``Revised paragraph 
identifiers'' table in the preamble of the NPRM. Paragraph (g) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), pertains to 
the terminating action in paragraph (r) of this AD; however, since that 
section of the preamble does not reappear in the final rule, no change 
to the AD is necessary. We also agree that the terminating action 
reference in paragraphs (h) and (j) of this AD should refer to 
paragraph (r) of this AD. We have changed paragraphs (h) and (j) of the 
final rule accordingly.

Request To Correct Certain Paragraph References

    Boeing asked that we correct the references to paragraphs (l)(1)(i) 
and (l)(1)(ii) of the NPRM (76 FR 47522, August 5, 2011) specified in 
paragraph (k)(1) of the NPRM to instead refer to paragraphs (k)(1)(i) 
and (k)(1)(ii) of the

[[Page 69750]]

NPRM. Boeing stated that paragraph (l) of the NPRM is related to 
auxiliary chord inspections, while paragraphs (k)(1)(i) and (k)(1)(ii) 
of the NPRM relate to the subject crack finding in paragraph (k)(1) of 
the NPRM.
    We agree there is a typographical error in paragraph (k)(1) of the 
NPRM (76 FR47522, August 5, 2011). Paragraph (l) of the NPRM does not 
include any subparagraphs and should not have been referenced in 
paragraph (k)(1) of the NPRM. We have corrected paragraph (k)(1) of the 
final rule accordingly to refer to paragraph (k)(1)(i) or (k)(1)(ii) of 
this AD.
    In addition, we have clarified paragraph (r) of this AD by 
referring to inspection paragraphs (g) through (o) of this AD and 
removing references to paragraphs (p) and (q) of this AD.

Clarification of Service Information Reference

    We have removed the service information referenced in paragraph 
(k)(2) of the NPRM (76 FR47522, August 5, 2011) because it is redundant 
to the service information specified in paragraph (k) of the NPRM. 
Paragraph (k) of the final rule specifies to accomplish (k)(1) or 
(k)(2) of the final rule in accordance with the service information 
specified in paragraph (k) of the final rule.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously--and minor editorial 
changes. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM (76 FR 47522, August 5, 2011) for correcting the unsafe condition; 
and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 47522, August 5, 2011).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of the AD.

Costs of Compliance

    We estimate that this AD affects 574 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Number of
              Action                      Labor cost          Parts cost   Cost per  product       U.S.                Cost on U.S. operators
                                                                                                airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Various inspections (retained      4 work-hours x $85 per             $0  $340 per inspection          296  $100,640 per inspection cycle.
 actions from AD 95-12-17,          hour = $340 per                        cycle.
 Amendment 39-9268 (60 FR 36981,    inspection cycle.
 July 19, 1995)).
Ultrasonic inspection (new         13 work-hours x $85 per             0  $1,105 per                   574  $634,270 per inspection cycle.
 action).                           hour = $1,105 per                      inspection cycle.
                                    inspection cycle.
Detailed and HFEC inspections      13 work-hours x $85 per             0  $1,105 per                   574  $634,270 per inspection cycle.
 (new actions).                     hour = $1,105 per                      inspection cycle.
                                    inspection cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs that 
would be required based on the results of the inspections. We have no 
way of determining the number of aircraft that might need these 
repairs:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost per
                    Action                                    Labor cost                 Parts cost    product
----------------------------------------------------------------------------------------------------------------
Optional modification (retained action from AD  50 work-hours x $85 per hour = $4,250.       $3,680       $7,930
 95-12-17, Amendment 39-9268 (60 FR 36981,
 July 19, 1995)).
Repair of cracking of the outboard chord frame  514 work hours x $85 per hour =              13,586       57,276
                                                 $42,690.
Time-limited repair cracking of the outboard    63 work hours x $85 per hour = $5,355.        2,732        8,087
 chord frame.
Repair of cracking of the outboard chord......  49 work hours x $85 per hour = $4,165.        4,255        8,420
----------------------------------------------------------------------------------------------------------------

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 AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (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),
    (3) Will not affect intrastate aviation in Alaska, and

[[Page 69751]]

    (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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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) 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), and adding 
the following new AD:

2012-23-04 The Boeing Company: Amendment 39-17260; Docket No. FAA-
2011-0722; Directorate Identifier 2010-NM-262-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective December 26, 
2012.

(b) Affected ADs

    This AD supersedes AD 95-12-17, Amendment 39-9268 (60 FR 36981, 
July 19, 1995).

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by several reports of fatigue cracking in 
the frame outboard chord at body station (BS) 727, and cracks in the 
radius of the auxiliary chord on airplanes that were not affected by 
the existing AD (60 FR 36981, July 19, 1995). We are issuing this AD 
to detect and correct fatigue cracking of the outboard and auxiliary 
chords, which could result in reduced structural integrity of the 
outboard chord and consequent rapid decompression of the airplane.

(f) Compliance

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

(g) Retained Initial Inspection: BS 727 Frame Chord Has Been Replaced

    This paragraph restates the requirements of paragraph (a) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), with 
revised service information. For Model 737-100 and -200 series 
airplanes having line numbers 1 through 999 inclusive, on which the 
BS 727 frame upper outboard chord has been replaced as specified in 
Boeing Service Bulletin 737-53-1088: Prior to the accumulation of 
30,000 flight cycles since replacement of the upper outboard chord, 
or within 4,500 flight cycles after August 18, 1995 (the effective 
date of AD 95-12-17) whichever occurs later, perform close visual, 
pulse echo shear wave (PESW), and high frequency eddy current (HFEC) 
inspections to detect cracks in the outboard chord of the frame at 
BS 727, in accordance with Part I of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-53A1166, dated June 30, 1994; 
Boeing Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; 
or Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 
25, 2006; as applicable. As of the effective date of this AD, use 
only Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated 
May 25, 2006, to accomplish the actions required by this paragraph.

(h) Retained Repetitive Inspections: BS 727 Frame Chord Has Been 
Replaced

    This paragraph restates the requirements of paragraph (b) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), with 
revised service information. For Model 737-100 and -200 series 
airplanes having line numbers 1 through 999 inclusive, on which the 
BS 727 frame upper outboard chord has been replaced as specified in 
Boeing Service Bulletin 737-53-1088: Repeat the inspections required 
by paragraph (g) of this AD at the time specified in paragraphs 
(h)(1), (h)(2), (h)(3), and (h)(4) of this AD, as applicable, until 
the optional terminating action described in paragraph (r) of this 
AD is accomplished.
    (1) If, at the time of the most recent inspection required by 
paragraph (g) or (h) of this AD, the airplane has accumulated 27,000 
or more flight cycles, but fewer than 50,000 flight cycles since the 
replacement of the outboard chord: Perform the next inspection 
within 15,000 flight cycles. Repeat the inspection thereafter at 
intervals not to exceed 15,000 flight cycles until the airplane has 
accumulated 50,000 or more flight cycles since the replacement of 
the outboard chord. Do the inspections required by paragraph (h)(2) 
of this AD at the time specified.
    (2) If, at the time of the most recent inspection required by 
paragraph (g) or (h) of this AD, the airplane has accumulated 50,000 
or more flight cycles, but fewer than 60,000 flight cycles, since 
the replacement of the outboard chord: Perform the next inspection 
within 7,500 flight cycles. Repeat the inspection thereafter at 
intervals not to exceed 7,500 flight cycles until the airplane has 
accumulated 60,000 or more flight cycles since the replacement of 
the outboard chord. Do the inspections required by paragraph (h)(3) 
of this AD at the time specified.
    (3) If, at the time of the most recent inspection required by 
paragraph (g) or (h) of this AD, the airplane has accumulated 60,000 
or more flight cycles, but fewer than 70,000 flight cycles, since 
the replacement of the outboard chord: Perform the next inspection 
within 5,000 flight cycles. Repeat the inspection thereafter at 
intervals not to exceed 5,000 flight cycles until the airplane has 
accumulated 70,000 or more flight cycles since the replacement of 
the outboard chord. Do the inspections required by paragraph (h)(4) 
of this AD at the time specified.
    (4) If, at the time of the most recent inspection required by 
paragraph (g) or (h) of this AD, the airplane has accumulated 70,000 
or more flight cycles since replacement of the outboard chord: 
Perform the next inspection within 3,000 flight cycles. Repeat the 
inspection thereafter at intervals not to exceed 3,000 flight 
cycles.

(i) Retained Initial Inspection: BS 727 Frame Chord Has Not Been 
Replaced or Only Lower Outboard Chord Has Been Replaced

    This paragraph restates the requirements of paragraph (c) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), with 
revised service information. For Model 737-100 and -200 series 
airplanes having line numbers 1 through 999 inclusive, on which the 
BS 727 frame outboard chord has not been replaced, or on which only 
the lower outboard chord has been replaced as specified in Boeing 
Service Bulletin 737-53-1088: Perform close visual, PESW, and HFEC 
inspections to detect cracks in the outboard chord of the frame at 
BS 727, in accordance with Part I of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-53A1166, dated June 30, 1994; 
Boeing Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; 
or Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 
25, 2006; as applicable. As of the effective date of this AD, use 
only Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated 
May 25, 2006, to accomplish the actions required by this paragraph. 
Perform these inspections initially at the time specified in 
paragraph (i)(1), (i)(2), (i)(3), or (i)(4) of this AD, as 
applicable.
    (1) For airplanes that have accumulated 27,000 or more total 
flight cycles, but fewer than 50,000 total flight cycles, as of 
August 18, 1995 (the effective date of AD 95-12-17, Amendment 39-
9268 (60 FR 36981, July 19, 1995)): Inspect within 4,500 flight 
cycles after August 18, 1995.
    (2) For airplanes that have accumulated 50,000 or more total 
flight cycles, but fewer than 60,000 total flight cycles, as of 
August 18, 1995 (the effective date of AD 95-12-17, Amendment 39-
9268 (60 FR 36981, July 19, 1995)): Inspect within 2,500 flight 
cycles after August 18, 1995.
    (3) For airplanes that have accumulated 60,000 or more total 
flight cycles, but fewer than 70,000 total flight cycles as of 
August 18, 1995 (the effective date of AD 95-12-17, Amendment 39-
9268 (60 FR 36981, July 19, 1995)): Inspect within 1,500 flight 
cycles after August 18, 1995.
    (4) For airplanes that have accumulated 70,000 or more total 
flight cycles as of August 18, 1995 (the effective date of AD 95-12-
17, Amendment 39-9268 (60 FR 36981, July 19, 1995)): Inspect within 
500 flight cycles or 90

[[Page 69752]]

days after August 18, 1995, whichever occurs first.

(j) Retained Repetitive Inspections: BS 727 Frame Chord Has Been 
Replaced or Only Lower Outboard Chord Has Been Replaced

    This paragraph restates the requirements of paragraph (d) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), with 
revised service information. For Model 737-100 and -200 series 
airplanes having line numbers 1 through 999 inclusive, on which the 
BS 727 frame outboard chord has not been replaced, or on which only 
the lower outboard chord has been replaced as specified in Boeing 
Service Bulletin 737-53-1088: Repeat the inspections required by 
paragraph (i) of this AD at the time specified in paragraphs (j)(1), 
(j)(2), (j)(3), and (j)(4) of this AD, as applicable, until the 
optional terminating action described in paragraph (r) of this AD is 
accomplished.
    (1) If, at the time of the most recent inspection required by 
paragraph (i) or (j) of this AD, the airplane has accumulated 27,000 
or more total flight cycles, but fewer than 50,000 total flight 
cycles: Perform the next inspection within 15,000 flight cycles. 
Repeat the inspection thereafter at intervals not to exceed 15,000 
flight cycles until the airplane has accumulated 50,000 or more 
total flight cycles. Do the inspections required by paragraph (j)(2) 
of this AD at the time specified.
    (2) If, at the time of the most recent inspection required by 
paragraph (i) or (j) of this AD, the airplane has accumulated 50,000 
or more total flight cycles, but fewer than 60,000 total flight 
cycles: Perform the next inspection within 7,500 flight cycles. 
Repeat the inspection thereafter at intervals not to exceed 7,500 
flight cycles until the airplane has accumulated 60,000 or more 
total flight cycles. Do the inspections required by paragraph (j)(3) 
of this AD at the time specified.
    (3) If, at the time of the most recent inspection required by 
paragraph (i) or (j) of this AD, the airplane has accumulated 60,000 
or more total flight cycles, but fewer than 70,000 total flight 
cycles: Perform the next inspection within 5,000 flight cycles. 
Repeat the inspection thereafter at intervals not to exceed 5,000 
flight cycles until the airplane has accumulated 70,000 or more 
total flight cycles. Do the inspections required by paragraph (j)(4) 
of this AD at the time specified.
    (4) If, at the time of the most recent inspection required by 
paragraph (i) or (j) of this AD, the airplane has accumulated 70,000 
or more total flight cycles: Perform the next inspection within 
3,000 flight cycles. Repeat the inspection thereafter at intervals 
not to exceed 3,000 flight cycles.

(k) Retained Repair, Replacement, and Additional Inspections

    This paragraph restates the requirements of paragraph (f) of AD 
95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), with 
revised service information. If any crack is found in the outboard 
chord of the frame at BS 727 during any inspection required by 
paragraphs (g) through (j) of this AD, accomplish paragraph (k)(1) 
or (k)(2) of this AD, as applicable, in accordance with Boeing Alert 
Service Bulletin 737-53A1166, dated June 30, 1994; Boeing Service 
Bulletin 737-53A1166, Revision 1, dated May 25, 1995; or Boeing 
Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006; 
as applicable. As of the effective date of this AD, use only Boeing 
Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, 
to accomplish the actions required by this paragraph.

    Note 1 to paragraph (k) of this AD:  Boeing Alert Service 
Bulletin 737-53A1166, dated June 30, 1994; Boeing Service Bulletin 
737-53A1166, Revision 1, dated May 25, 1995; and Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006; refer 
to either Boeing Service Bulletin 737-53-1088, dated December 14, 
1989; or Boeing Service Bulletin 737-53-1088, Revision 1, dated May 
25, 2006; as an additional source of guidance for procedures to 
replace the chord.

    (1) For any crack that extends from the forward edge of the 
chord or from the forward fastener hole, but that does not extend 
past the second fastener hole, accomplish the actions specified in 
either paragraph (k)(1)(i) or (k)(1)(ii) of this AD. Thereafter, 
perform initial and repetitive inspections in accordance with 
paragraphs (g) and (h) of this AD.
    (i) Prior to further flight, install the time limited repair. 
Within 4,500 flight cycles or within 18 months after accomplishing 
the time-limited repair, whichever occurs first, replace the 
outboard chord. Or
    (ii) Prior to further flight, replace the outboard chord.
    (2) For any crack that extends from the forward edge of the 
chord, or from the forward fastener hole, and that extends past the 
second fastener hole, prior to further flight, replace the outboard 
chord. Thereafter, perform initial and repetitive inspections in 
accordance with paragraphs (g) and (h) of this AD.

(l) New Initial and Repetitive Inspections: BS 727 Auxiliary Chord

    For airplanes identified in table 5 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006: Before the accumulation of 27,000 
total flight cycles, or within 5,000 flight cycles after the 
effective date of this AD, whichever occurs later, do internal 
detailed and HFEC inspections to detect cracks in the auxiliary 
chord radius of the frame at BS 727, in accordance with Part 1 of 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1166, Revision 2, dated May 25, 2006. Repeat the inspections 
thereafter at intervals not to exceed 15,000 flight cycles until the 
optional terminating action described in paragraph (r) of this AD is 
accomplished. If any crack is found, before further flight, repair 
in accordance with the requirements of paragraph (s) of this AD.

(m) New Initial and Repetitive Inspections: BS 727 Frame Chord Has Not 
Been Replaced and Has Not Been Modified

    For airplanes identified in table 2 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006: Do the applicable inspections 
required by paragraph (m)(1) or (m)(2) of this AD at the time 
specified, in accordance with Part 1 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision 
2, dated May 25, 2006. Except as required by paragraph (p) of this 
AD, if any crack is found during any inspection required by 
paragraph (m)(1) or (m)(2) of this AD, before further flight, repair 
in accordance with Part 3 or Part 4 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision 
2, dated May 25, 2006, as applicable. Repeat the inspections until 
the optional terminating action described in paragraph (r) of this 
AD is accomplished. Accomplishing the inspections in this paragraph 
ends the inspections required by paragraphs (i) and (j) of this AD.
    (1) For airplanes on which the inspections specified in Boeing 
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing 
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have 
not been performed as of the effective date of this AD: Do the 
inspections required by paragraphs (m)(1)(i) and (m)(1)(ii) of this 
AD at the time specified.
    (i) Before the accumulation of 27,000 total flight cycles, or 
within 5,000 flight cycles after the effective date of this AD, 
whichever occurs later: Do ultrasonic and surface HFEC inspections 
to detect cracks in the forward flange of the outboard chord of the 
frame at BS 727. Repeat the inspections thereafter at intervals not 
to exceed 5,000 flight cycles.
    (ii) Before the accumulation of 27,000 total flight cycles, or 
within 10,000 flight cycles after the effective date of this AD, 
whichever occurs later: Do an open hole eddy current inspection to 
detect cracks in the forward flange of the outboard chord of the 
frame at BS 727. Repeat the inspection thereafter at intervals not 
to exceed 15,000 flight cycles.
    (2) For airplanes on which the inspections specified in Boeing 
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing 
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have 
been performed as of the effective date of this AD: Repeat the 
applicable inspection specified in paragraphs (m)(1)(i) and 
(m)(1)(ii) of this AD thereafter at intervals not to exceed 5,000 
flight cycles for the ultrasonic and surface HFEC inspections, and 
at intervals not to exceed 15,000 flight cycles for the open hole 
eddy current inspection.

(n) New Initial and Repetitive Inspections: BS 727 Frame Chord Has Been 
Replaced and Has Not Been Modified

    For airplanes identified in table 3 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006: Do the applicable inspections 
required by paragraph (n)(1) or (n)(2) of this AD at the time 
specified, in accordance with Part 1 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision 
2, dated May 25, 2006. Except as required by paragraph (p) of this 
AD, if any crack is found during any inspection required by 
paragraph (n)(1) or (n)(2) of this AD, before

[[Page 69753]]

further flight, repair in accordance with Part 3 or Part 4, as 
applicable, of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006. Repeat 
the inspections until the optional terminating action described in 
paragraph (r) of this AD is accomplished. Accomplishing the 
inspections in this paragraph ends the inspections required by 
paragraphs (g) and (h) of this AD. The detailed and eddy current 
inspections of the outboard chord of S-18A specified in Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, are 
not required by this AD.
    (1) For airplanes on which the inspections specified in Boeing 
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing 
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have 
not been done as of the effective date of this AD: Do the 
inspections required by paragraphs (n)(1)(i) and (n)(1)(ii) of this 
AD at the time specified.
    (i) Within 27,000 flight cycles since replacement of the upper 
outboard chord, or within 5,000 flight cycles after the effective 
date of this AD, whichever occurs later: Do ultrasonic, low 
frequency eddy current, and edge HFEC inspections to detect cracks 
in the forward flange of the outboard chord of the frame at BS 727. 
Repeat the inspections thereafter at intervals not to exceed 5,000 
flight cycles.
    (ii) Within 27,000 flight cycles since replacement of the upper 
outboard chord, or within 10,000 flight cycles after the effective 
date of this AD, whichever occurs later: Do an open hole eddy 
current inspection to detect cracks in the forward flange of the 
outboard chord of the frame at BS 727. Repeat the inspections 
thereafter at intervals not to exceed 15,000 flight cycles.
    (2) For airplanes on which the inspections specified in Boeing 
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing 
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have 
been done as of the effective date of this AD: Repeat the applicable 
inspection specified in paragraphs (n)(1)(i) and (n)(1)(ii) of this 
AD thereafter at intervals not to exceed 5,000 flight cycles for the 
ultrasonic, low frequency eddy current, and edge HFEC inspections, 
and at intervals not to exceed 15,000 flight cycles for the open 
hole eddy current inspection.

(o) New One-Time Inspection: BS 727 Frame Chord Has Been Modified

    For airplanes identified in table 4 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006: Within 60,000 flight cycles after 
accomplishing the modification of the outboard chord of the frame at 
BS 727 at S-18A, but no earlier than 50,000 flight cycles after 
accomplishing the modification; do a one-time follow-on open hole 
eddy current inspection to detect cracks in the modified chord, in 
accordance with Part 8 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006. 
Except as required by paragraph (p) of this AD, if any crack is 
found during the inspection required by this paragraph, before 
further flight, repair in accordance with Part 3 or Part 4, as 
applicable, of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006.

(p) New Repairs

    If any crack is found during any inspection required by 
paragraphs (m), (n), or (o) of this AD, and the repairs specified in 
Part 3 and Part 4 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, cannot 
be installed using the procedures identified in this service 
bulletin: Before further flight, repair using a method approved in 
accordance with the procedures specified in paragraph (s) of this 
AD.

(q) New Replacement of Time-Limited Repair

    For any airplane on which a time-limited repair is installed on 
the outboard chord of the frame at body station BS 727 as specified 
in Boeing Alert Service Bulletin 737-53A1166, dated June 30, 1994; 
Boeing Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; 
or Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 
25, 2006: Within 4,500 flight cycles after installation of the 
repair, or within 6 months after the effective date of this AD, 
whichever occurs later, replace the repair in accordance with Part 9 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1166, Revision 2, dated May 25, 2006.

(r) New Optional Terminating Action

    Accomplishment of the applicable action specified in paragraph 
(r)(1) or (r)(2) of this AD, in accordance with Part 2 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1166, dated June 30, 1994; Part II of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53A1166, Revision 1, 
dated May 25, 1995; or Part 6 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 25, 
2006; constitutes terminating action for the inspections required by 
paragraphs (g) through (o) this AD.
    (1) Installation of the preventative modification.
    (2) Replacement of the cracked chord and installation of the 
preventative modification.

(s) Alternative Methods of Compliance (AMOCs)

    (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. 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 the Related Information 
section of this AD. Information may be emailed to: <a href="/cdn-cgi/l/email-protection#f8c1d5b9b6b5d5ab9d998c8c949dd5b9bbb7d5b9b5b7bbd5aa9d898d9d8b8c8bb89e9999d69f978e"><span class="__cf_email__" data-cfemail="5e67731f1013730d3b3f2a2a323b731f1d11731f13111d730c3b2f2b3b2d2a2d1e383f3f70393128">[email&#160;protected]</span></a>.
    (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 required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation 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, and the approval must 
specifically refer to this AD.
    (4) AMOCs approved previously in accordance with AD 95-12-17, 
Amendment 39-9268 (60 FR 36981, July 19, 1995), are approved as 
AMOCs for the corresponding provisions of this AD.
    (5) For airplanes identified in Tables 2, 3, and 5 of paragraph 
1.E., ``Compliance'' of Boeing Alert Service Bulletin 737-53A1166, 
Revision 2, dated May 25, 2006: The Manager, Seattle ACO, approves 
the inspection methods, thresholds, and repetitive intervals defined 
in Appendix A, Table 1, of Boeing Alert Service Bulletin 737-
53A1166, Revision 2, dated May 25, 2006, as an AMOC for the 
inspections of the structurally significant items (SSIs) identified 
in paragraphs (s)(5)(i) and (s)(5)(ii) of this AD. This approval 
applies only to SSIs F-29A and F-29B of the applicable supplemental 
structural inspection document (SSID) and only for the portions of 
the BS 727 outer chord that have been inspected or that have been 
repaired or modified in accordance with Boeing Alert Service 
Bulletin 737-53A1166, Revision 2, dated May 25, 2006. All provisions 
of ADs 2008-08-23, Amendment 39-15477 (73 FR 21237, April 21, 2008); 
and 2008-09-13, Amendment 39-15494 (73 FR 24164, May 2, 2008); that 
are not specifically referenced in this paragraph remain fully 
applicable and must be done. If operators choose this AMOC, they 
must revise their FAA-approved maintenance or inspection program to 
incorporate the alternative inspections in this paragraph.
    (i) Inspections of SSIs F-29A and F-29B required by paragraphs 
(g) and (h) of AD 2008-08-23, Amendment 39-15477 (73 FR 21237, April 
21, 2008), which applies to Model 737-200C series airplanes (Boeing 
737-100/200/200C SSID D6-37089, Revision E, dated May 1, 2007).
    (ii) Inspections of SSIs F-29A and F-29B required by paragraphs 
(g) and (h) of AD 2008-09-13, Amendment 39-15494 (73 FR 24164, May 
2, 2008), which applies to Model 737-300, -400, and -500 series 
airplanes (Boeing 737-300/400/500 SSID D6-82669, dated May 1, 2007).

(t) Related Information

    For more information about this AD, contact Alan Pohl, Aerospace 
Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind 
Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-6450; 
fax: (425) 917-6590; email: <a href="/cdn-cgi/l/email-protection#a9c8c5c8c787d9c6c1c5e9cfc8c887cec6df"><span class="__cf_email__" data-cfemail="72131e131c5c021d1a1e321413135c151d04">[email&#160;protected]</span></a>.

(u) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

[[Page 69754]]

    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (3) The following service information was approved for IBR on 
December 26, 2012.
    (i) Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated 
May 25, 2006.
    (ii) Reserved.
    (4) The following service information was approved for IBR on 
August 18, 1995 (60 FR 36981, July 19, 1995).
    (i) Boeing Alert Service Bulletin 737-53A1166, dated June 30, 
1994, including Addendum, approved for IBR August 18, 1995 (60 FR 
36981, July 19, 1995).
    (ii) Boeing Service Bulletin 737-53A1166, Revision 1, dated May 
25, 1995, including Addendum, approved for IBR August 18, 1995 (60 
FR 36981, July 19, 1995).
    (5) For Boeing service information identified in this 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; Internet 
<a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>.
    (6) You may view this service information at 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.
    (7) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.

    Issued in Renton, Washington, on October 16, 2012.
John P. Piccola,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-27636 Filed 11-20-12; 8:45 am]
BILLING CODE 4910-13-P