Airworthiness Directives; Boeing Model 737 Airplanes

[Federal Register Volume 70, Number 241 (Friday, December 16, 2005)]
[Rules and Regulations]
[Pages 74647-74649]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-24151]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-21712; Directorate Identifier 2005-NM-070-AD; 
Amendment 39-14424; AD 2005-26-03]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737 Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Boeing Model 737 airplanes. This AD requires modifying the 
elevator input torque tube assembly. This AD results from a report of a 
restriction in the pilot's elevator input control system. A design 
review performed on the elevator input torque tube assembly in the 
course of the investigation discovered possible failure modes that 
could lead to a jam of the elevator control system. We are issuing this 
AD to prevent loss of elevator control and consequent reduced 
controllability of the airplane.

DATES: This AD becomes effective January 20, 2006.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of January 20, 
2006.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Douglas Tsuji, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6487; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain Boeing Model 
737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800 and -
900 series airplanes. That NPRM was published in the Federal Register 
on July 5, 2005 (70 FR 38630). That NPRM proposed to require modifying 
the elevator input torque tube assembly.

Comments

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

Support for the Proposed AD

    One commenter states that although the proposed AD does not affect 
any airplane in its fleet, it supports the actions in the AD.

Request To Clarify Summary

    The airplane manufacturer requests that we revise the third 
sentence in the Summary section of the proposed AD from, ``This 
proposed AD is prompted by a report of a restriction in the pilot's 
elevator control system,'' to ``This proposed AD is prompted by the 
results of a design review performed on the input torque tube assembly, 
which discovered possible failure modes that could lead to a jam of the 
elevator control system.'' The commenter explains that the sentence, as 
proposed, may be misleading by connecting the pilots' reported 
condition to the hypothetical jam that is addressed by the proposed AD.
    We partially agree with the commenter. We agree that the wording in 
the Summary section could lead to an interpretation that the cause of 
the reported incident was restrictions in the pilot's elevator input 
control system. We disagree with revising the section as proposed, 
because, as stated in the Discussion section of the proposed AD, the 
design review was conducted as part of an intensive investigation. The 
investigation was conducted by the National Transportation Safety 
Board, the FAA, and Boeing. We have revised the Summary section and 
paragraph (d) of the final rule to state, ``This AD results from a 
report of a restriction in the pilot's elevator input control system. A 
design review performed on the elevator input torque tube assembly in 
the course of the investigation discovered possible failure modes that 
could lead to a jam of the elevator control system.''

Request To Allow Different Procedures for Re-Identification

    The commenter, an airplane operator, requests that paragraph (f) be 
revised to allow alternate methods for re-identifying the modified 
elevator torque tube assemblies. The commenter explains that the 
service bulletins referenced in the proposed AD specify the use of a 
rubber ink stamp method to re-identify the modified assemblies. The 
commenter points out that operators of a single airplane would have to 
fabricate or acquire a stamp for a one-time use, and operators of many 
airplanes would have to acquire dozens of rubber stamps to support the 
various overhaul facility locations. The commenter requests that the 
final rule allow for use of either the rubber stamp method, or the use 
of a pen with indelible ink. The commenter states that the component 
number could then be covered with protective covering.
    We agree with the commenter. The intent of the procedures in the 
proposed AD and in the service bulletins is to signify that the 
modification has been accomplished, not to specify the method of re-
identification. We have revised paragraph (f) of the final rule to 
allow alternate permanent part marking in lieu of rubber stamping.

[[Page 74648]]

Clarification of Alternative Method of Compliance (AMOC) Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any approved AMOC on 
any airplane to which the AMOC applies.

Conclusion

    We have carefully reviewed the available data, including the 
comments 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 2,971 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 1,573 airplanes of U.S. 
registry. The following table provides the estimated costs for U.S. 
operators to comply with this AD.

                                                                     Estimated Costs
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                                                                                                                               U.S.
                      Modification                          Work hours     Average labor       Parts         Cost per       registered      Fleet cost
                                                                           rate per hour                     airplane        airplanes
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For airplanes identified in Boeing Alert Service                       5             $65            $701          $1,026             249        $255,474
 Bulletin 737-27A1271 as Group 1........................
For airplanes identified in Boeing Alert Service                       7              65           1,290           1,745             311         542,695
 Bulletin 737-27A1271 as Group 2........................
For all airplanes identified in Boeing Alert Service                   3              65              50             245           1,013         248,185
 Bulletin 737-27A1274...................................
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In addition, a special tool is necessary to do the modification 
required by this AD. Boeing will provide one tool at no charge to each 
customer regardless of warranty status.
    Based on these figures, the estimated total cost of this AD for 
U.S. operators is about $1,046,354, or between $1,271 and $1,990 per 
airplane.

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); 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 
adding the following new airworthiness directive (AD):

2005-26-03 Boeing: Amendment 39-14424. Docket No. FAA-2005-21712; 
Directorate Identifier 2005-NM-070-AD.

Effective Date

    (a) This AD becomes effective January 20, 2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the airplanes identified in Table 1 of 
this AD, certificated in any category.

                 Table 1.--Airplanes Affected by This AD
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                                          As identified in Boeing Alert
        Boeing airplane models--                Service Bulletin--
------------------------------------------------------------------------
737-100, -200, -200C, -300, -400, and -  737-27A1274, dated February 17,
 500 series airplanes.                    2005.
737-600, -700, -700C, -800 and -900      737-27A1271, dated December 16,
 series airplanes.                        2004.
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[[Page 74649]]

Unsafe Condition

    (d) This AD results from a report of a restriction in the 
pilot's elevator input control system. Although the cause of the 
incident was indeterminate, a design review performed on the 
elevator input torque tube assembly in the course of the 
investigation discovered possible failure modes that could lead to a 
jam of the elevator control system. We are issuing this AD to 
prevent loss of elevator control and consequent reduced 
controllability of the airplane.

Compliance

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

Modification

    (f) Within 60 months after the effective date of this AD: Modify 
the elevator input torque tube assembly by doing all the actions in 
accordance with the Accomplishment Instructions of the applicable 
service bulletin in Table 1 of this AD. Where the applicable service 
bulletin specifies to re-identify the modified elevator torque tube 
assemblies using a rubber stamp, the part may be re-identified using 
a permanent method that is acceptable to the appropriate principal 
inspector in the FAA Flight Standards Certificate Holding District 
Office.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (h) You must use Boeing Alert Service Bulletin 737-27A1274, 
dated February 17, 2005; or Boeing Alert Service Bulletin 737-
27A1271, dated December 16, 2004; as applicable, to perform the 
actions that are required by this AD, unless the AD specifies 
otherwise. The Director of the Federal Register approved the 
incorporation by reference of these documents in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial 
Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy 
of this service information. You may review copies at the Docket 
Management Facility, U.S. Department of Transportation, 400 Seventh 
Street SW., room PL-401, Nassif Building, Washington, DC; on the 
Internet at http://dms.dot.gov; or at 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.


    Issued in Renton, Washington, on November 25, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-24151 Filed 12-15-05; 8:45 am]
BILLING CODE 4910-13-P

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