Airworthiness Directives; The Boeing Company Model 737-300, -400, and -500 Series Airplanes

[Federal Register Volume 76, Number 34 (Friday, February 18, 2011)]
[Rules and Regulations]
[Pages 9498-9501]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-3651]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0379; Directorate Identifier 2009-NM-210-AD; 
Amendment 39-16609; AD 2011-04-10]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-300, -400, 
and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to all Model 737-300, -400, and -500 series 
airplanes. That AD currently requires inspecting to determine if 
certain carriage spindles are installed, repetitive inspections for 
corrosion and indications of corrosion on affected carriage spindles, 
and if necessary, related investigative and corrective actions. That AD 
also provides an optional terminating action. This new AD mandates the 
optional terminating action, which eliminates the need for the 
repetitive inspections. This AD results from reports of corrosion found 
on carriage spindles that are located on the outboard trailing edge 
flaps. We are issuing this AD to detect and correct corrosion of the 
carriage spindle, which could result in fracture.

[[Page 9499]]

Fracture of both the inboard and outboard carriage spindles, in the 
forward ends through the large diameters, on a flap, could adversely 
affect the airplane's continued safe flight and landing.

DATES: This AD becomes effective March 25, 2011.
    On November 24, 2009 (74 FR 57564, November 9, 2009), the Director 
of the Federal Register approved the incorporation by reference of a 
certain publication listed in the AD.
    On August 5, 2008 (73 FR 42259, July 21, 2008), the Director of the 
Federal Register approved the incorporation by reference of a certain 
other publication listed in the AD.

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; e-mail [email protected]; 
Internet https://www.myboeingfleet.com.

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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the 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: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6440; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 2009-23-10, Amendment 
39-16084 (74 FR 57564, November 9, 2009). The existing AD applies to 
all Model 737-300, -400, and -500 series airplanes. That NPRM was 
published in the Federal Register on April 8, 2010 (75 FR 17882). That 
NPRM proposed to continue to require inspecting to determine if certain 
carriage spindles are installed, repetitive inspections for corrosion 
and indications of corrosion on affected carriage spindles, and if 
necessary, related investigative and corrective actions. The existing 
AD also provides an optional terminating action. That NPRM also 
proposed to mandate the optional terminating action, which would 
eliminate the need for the repetitive inspections.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments that have been 
received on the NPRM.

Request To Revise Paragraph (k) of the NPRM

    Boeing, Continental Airlines (CAL), and British Airways Plc 
requested that paragraph (k) of the NPRM be revised to identify 
additional replacement parts for the affected high velocity oxy-fuel 
(HVOF)-coated spindles. (Paragraph (k) of the NPRM proposed to require 
replacement of HVOF-coated carriage spindles having serial numbers 
identified in Table 2 or 3 of Appendix A of Boeing Service Bulletin 
737-57A1304, Revision 1, dated August 11, 2009, with either a non-HVOF-
coated carriage spindle, or with a serviceable HVOF-coated carriage 
spindle with an `R' suffix on the serial number. Tables 2 and 3 of that 
service bulletin identify both part numbers and serial numbers of the 
affected carriage spindles.)
    Boeing requested that we revise paragraph (k) of the NPRM to 
specify that ``new'' HVOF-coated carriage spindles with serial numbers 
not listed in Table 2 or 3 of Appendix A of the referenced Boeing 
service bulletin are also acceptable replacements.
    British Airways Plc requested that we revise paragraph (k) of the 
NPRM to add ``serviceable'' carriage spindles not listed in Table 2 or 
3 of Appendix A of the referenced Boeing service bulletin as acceptable 
replacements.
    CAL noted that there is no mention in paragraph (k) of the NPRM of 
``serviceable,'' non-suspect HVOF-coated carriage spindles that do not 
have an `R' suffix. CAL indicated that those particular carriage 
spindles are not listed in Tables 2 and 3 of Appendix A and, therefore, 
are not affected by the NPRM. In light of this, CAL requested that 
paragraph (k) of the NPRM be revised to specify that the repetitive 
inspections can be terminated by replacing affected HVOF-coated 
carriage spindles with serviceable, non-suspect HVOF-coated carriage 
spindles that do not have an `R' suffix.
    We agree with the commenters' requests. We have revised paragraph 
(j) of the final rule (paragraph (k) of the NPRM) to include the 
following carriage spindles as acceptable replacements: (1) Non-HVOF-
coated carriage spindles; (2) new or serviceable HVOF-coated carriage 
spindles having serial numbers that are NOT identified in Table 2 or 
Table 3 of Appendix A of Boeing Service Bulletin 737-57A1304, Revision 
1, dated August 11, 2009, without an `R' suffix on the serial number; 
and (3) serviceable HVOF-coated carriage spindles with an `R' suffix on 
the serial number.
    We also have removed paragraph (j), ``Parts Installation,'' of the 
NPRM. That paragraph was restated from AD 2009-23-10. Since terminating 
action is now available, the paragraph is no longer necessary.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been received, and determined that air safety and 
the public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 482 airplanes of the affected design in the 
worldwide fleet. This AD affects about 150 airplanes of U.S. registry.
    The inspection that is required by AD 2009-23-10 and retained in 
this AD takes about 2 work hours per airplane, at an average labor rate 
of $85 per work hour. Based on these figures, the estimated cost of the 
currently required inspection is $170 per airplane, per inspection 
cycle.
    The replacement of each affected carriage spindle that is required 
by this AD will take about 17 work hours per spindle (4 spindles per 
airplane), at an average labor rate of $85 per work hour. Required 
parts cost is provided under warranty. Based on these figures, the 
estimated cost of the replacement specified in this AD for U.S. 
operators is up to $867,000 or up to $5,780 per airplane, or $1,445 per 
carriage spindle.

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.

[[Page 9500]]

    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); 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-16084 (74 FR 57564, November 9, 2009) and by 
adding the following new airworthiness directive (AD):

2011-04-10 The Boeing Company: Amendment 39-16609. Docket No. FAA-
2010-0379; Directorate Identifier 2009-NM-210-AD.

Effective Date

    (a) This AD becomes effective March 25, 2011.

Affected ADs

    (b) This AD supersedes AD 2009-23-10, Amendment 39-16084.

Applicability

    (c) This AD applies to all The Boeing Company Model 737-300, -
400, and -500 series airplanes, certificated in any category.

Subject

    (d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

    (e) This AD results from reports of corrosion found on carriage 
spindles that are located on the outboard trailing edge flaps. The 
Federal Aviation Administration is issuing this AD to detect and 
correct corrosion of the carriage spindle, which could result in 
fracture. Fracture of both the inboard and outboard carriage 
spindles, in the forward ends through the large diameters, on a 
flap, could adversely affect the airplane's continued safe flight 
and landing.

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.

Restatement of Requirements of AD 2008-15-05, Amendment 39-15617

Inspection To Determine Affected Carriage Spindle

    (g) For all airplanes: Within 30 days after August 5, 2008 (the 
effective date of AD 2008-15-05), inspect the carriage sub-assembly 
to determine whether an affected carriage spindle with a high 
velocity oxy-fuel (HVOF) thermal coating is installed, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-57A1304, dated June 2, 2008. A review of airplane 
maintenance records is acceptable in lieu of this inspection if the 
part number and/or serial number of the carriage can be conclusively 
determined from that review. If no affected carriage spindle is 
installed, no further action is required by this paragraph.

Repetitive Inspections, Related Investigative Actions, and 
Corrective Action

    (h) For airplanes on which any affected carriage spindle was 
determined to be installed in accordance with Boeing Alert Service 
Bulletin 737-57A1304, dated June 2, 2008, as of August 5, 2008; and 
the spindle is identified in Table 2 of Boeing Service Bulletin 737-
57A1304, Revision 1, dated August 11, 2009: At the later of the 
times specified in paragraphs (h)(1) and (h)(2) of this AD, do a 
detailed inspection (or, as an option for the forward end of the 
spindle only, a borescope inspection technique may be used) of the 
spindle for corrosion and potential indications of corrosion of the 
carriage spindle, and do all applicable related investigative and 
corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-57A1304, dated 
June 2, 2008; or Boeing Service Bulletin 737-57A1304, Revision 1, 
dated August 11, 2009. Do all applicable related investigative and 
corrective actions before further flight. Repeat the detailed 
inspection (or, as an option for the forward end of the spindle 
only, the borescope inspection) and certain related investigative 
actions (i.e., the gap-check or optional non-destructive test (NDT) 
ultrasonic inspection) at the applicable compliance times specified 
in paragraph 1.E. of Boeing Alert Service Bulletin 737-57A1304, 
dated June 2, 2008; or Boeing Service Bulletin 737-57A1304, Revision 
1, dated August 11, 2009.
    (1) Within 30 days after August 5, 2008.
    (2) Within 90 days after the installation of a new HVOF-coated 
spindle.

    Note 1:  Boeing Alert Service Bulletin 737-57A1304, dated June 
2, 2008; and Boeing Service Bulletin 737-57A1304, Revision 1, dated 
August 11, 2009; reference Boeing Alert Service Bulletin 737-
57A1277, Revision 1, dated November 25, 2003; for further guidance 
on accomplishing the related investigative actions.

Restatement of Requirements of AD 2009-23-10, Amendment 39-16084

Repetitive Inspections, Related Investigative Actions, and 
Corrective Action for Certain Airplanes

    (i) For airplanes on which a carriage spindle having a serial 
number identified in Table 3 of Appendix A of Boeing Service 
Bulletin 737-57A1304, Revision 1, dated August 11, 2009, is 
installed: At the latest of the times specified in paragraphs 
(i)(1), (i)(2), and (i)(3) of this AD, as applicable, do a detailed 
inspection (or, as an option for the forward end of the spindle 
only, a borescope inspection technique may be used) of the spindle 
for corrosion and potential indications of corrosion of the carriage 
spindle, and do all applicable related investigative and corrective 
actions, in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin 737-57A1304, Revision 1, dated August 11, 
2009. Do all applicable related investigative and corrective actions 
before further flight. Repeat the detailed inspection (or, as an 
option for the forward end of the spindle only, the borescope 
inspection) and related investigative actions (i.e., the gap-check 
or optional NDT ultrasonic inspection) at the applicable compliance 
times specified in paragraph 1.E. of Boeing Service Bulletin 737-
57A1304, Revision 1, dated August 11, 2009.
    (1) Within 30 days after November 24, 2009 (the effective date 
of AD 2009-23-10).
    (2) Within 90 days after the installation of a new HVOF-coated 
spindle identified in Table 3 of Appendix A of Boeing Service 
Bulletin 737-57A1304, Revision 1, dated August 11, 2009.
    (3) Within 90 days after doing an inspection in accordance with 
Boeing Alert Service Bulletin 737-57A1304, dated June 2, 2008.

[[Page 9501]]

New Requirements of This AD

Terminating Action

    (j) Within 48 months after the effective date of this AD: 
Replace any HVOF-coated carriage spindle having a serial number 
identified in Table 2 or Table 3 of Appendix A of Boeing Service 
Bulletin 737-57A1304, Revision 1, dated August 11, 2009, with a non-
HVOF-coated carriage spindle; or a serviceable HVOF-coated carriage 
spindle with an `R' suffix on the serial number; or a new or 
serviceable HVOF-coated carriage spindle having a serial number not 
identified in Table 2 or Table 3 of Appendix A of Boeing Service 
Bulletin 737-57A1304, Revision 1, dated August 11, 2009, without an 
`R' suffix on the serial number; in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
57A1304, dated June 2, 2008; or Boeing Service Bulletin 737-57A1304, 
Revision 1, dated August 11, 2009. Replacing all affected carriage 
spindles terminates the repetitive inspections required by this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(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: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, 
FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6440; fax (425) 917-6590. Or, e-mail 
information to [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by the 
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 and the approval must 
specifically refer to this AD.

Material Incorporated by Reference

    (l) You must use Boeing Alert Service Bulletin 737-57A1304, 
dated June 2, 2008; and Boeing Service Bulletin 737-57A1304, 
Revision 1, dated August 11, 2009; as applicable; to do the actions 
required by this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register previously approved the 
incorporation by reference of Boeing Service Bulletin 737-57A1304, 
Revision 1, dated August 11, 2009, on November 24, 2009 (74 FR 
57564, November 9, 2009).
    (2) The Director of the Federal Register previously approved the 
incorporation by reference of Boeing Alert Service Bulletin 737-
57A1304, dated June 2, 2008, on August 5, 2008 (73 FR 42259, July 
21, 2008).
    (3) 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; e-mail 
[email protected]; Internet https://www.myboeingfleet.com.
    (4) You may review copies of the 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.
    (5) You may also review copies of the 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: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington on February 10, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-3651 Filed 2-17-11; 8:45 am]
BILLING CODE 4910-13-P

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