[Federal Register Volume 62, Number 10 (Wednesday, January 15, 1997)]
[Rules and Regulations]
[Pages 2007-2009]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-537]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-145-AD; Amendment 39-9881; AD 97-01-10]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737-100 and -200 series airplanes, 
that requires replacing the aileron (lateral) control transfer 
mechanism with a new modified mechanism, or reworking the existing 
mechanism. This amendment is prompted by a review of the design of the 
flight control systems on Model 737 series airplanes. The actions 
specified by this AD are intended to prevent unexpected, significant 
control wheel forces and reduced travel of a control wheel due to 
mechanical interference within the lateral control system transfer 
mechanism during a jam override condition.

DATES: Effective February 19, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 19, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, 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; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Don Kurle, Senior Engineer, Systems 
and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate, 
SeattleAircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2798; fax (206) 227-1181.

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 certain Boeing Model 737-100 and -
200 series airplanes was published in the Federal Register on August 
28, 1996 (61 FR 44230). That action proposed to require replacing the 
aileron (lateral) control transfer mechanism with a new modified 
mechanism, or reworking the existing mechanism.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    Two commenters support the proposed rule.

Request for Risk Benefit Analysis

    One commenter believes that the FAA should perform a risk benefit 
analysis before proceeding with the proposed AD. This commenter does 
not disagree with the requirements of the proposal; however, the 
commenter suggests that the proposed compliance time of 18 months could 
overburden competent machine facilities and lead to undesirable 
workmanship, which would subject the airlines and the flying public to 
unnecessary risk.
    The FAA does not concur with the commenter's request. The commenter 
did not submit analyses or data to substantiate its claim that 
competent machine facilities would be overburdened by the requirements 
of this AD. The FAA has considered the costs of complying with this AD, 
and does not consider those costs to be

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excessive to correct the unsafe condition.

Request To Revise Statement of Findings of Critical Design Review 
Team

    One commenter requests the second paragraph of the Discussion 
section that appeared in the preamble to the proposed rule be revised 
to accurately reflect the findings of the Critical Design Review (CDR) 
team. The commenter asks that the FAA delete the one sentence in that 
paragraph, which read: ``The recommendations of the team include 
various changes to the design of the flight control systems of these 
airplanes, as well as correction of certain design deficiencies.'' The 
commenter suggests that the following sentences should be added: ``The 
team did not find any design issues that could lead to a definite cause 
of the accidents that gave rise to this effort. The recommendations of 
the team include various changes to the design of the flight control 
systems of these airplanes, as well as incorporation of certain design 
improvements in order to enhance its already acceptable level of 
safety.''
    The FAA does not find that a revision to this final rule in the 
manner suggested by the commenter is necessary, since the Discussion 
section of a proposed rule does not reappear in a final rule. The FAA 
acknowledges that the CDR team did not find any design issue that could 
lead to a definite cause of the accidents that gave rise to this 
effort. However, as a result of having conducted the CDR of the flight 
control systems on Boeing Model 737 series airplanes, the team 
indicated that there are a number of recommendations that should be 
addressed by the FAA as may be appropriate to any particular (or all) 
model(s) of the Model 737.

Request To Revise Service Bulletin Citation

    One commenter requests that the FAA change the service bulletin 
citation from ``Boeing Service Bulletin 27-1033'' to ``Boeing Service 
Bulletin 737-27-1033.'' The commenter considers this to be clearer.
    The FAA acknowledges that some clarification is necessary. The 
title that actually appears on the service bulletin document itself is 
``Boeing Service Bulletin 27-1033;'' therefore, the FAA disagrees with 
the commenter's specific suggestion. However, to avoid any confusion on 
the part of operators, the FAA has revised the final rule to refer to 
the service bulletin as ``Boeing 737 Service Bulletin 27-1033.''

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 236 Model 737-100 and -200 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
157 airplanes of U.S. registry will be affected by this AD.
    For operators that elect to accomplish the replacement, it will 
take approximately 20 work hours per airplane to accomplish it, at an 
average labor rate of $60 per work hour. Required parts will cost 
approximately $15,343 per airplane. Based on these figures, the cost 
impact of the replacement on U.S. operators is estimated to be $16,543 
per airplane.
    For operators that elect to accomplish the rework by using new 
components, it will take approximately 40 work hours to accomplish it, 
at an average labor rate of $60 per work hour. Required parts will cost 
approximately $6,500. Based on these figures, the cost impact of the 
rework (by using new components) on U.S. operators is estimated to be 
$8,900 per airplane.
    For operators that elect to accomplish the rework by machine shop 
rework of the components, it will take approximately 70 work hours to 
accomplish it, at an average labor rate of $60 per work hour. Required 
parts will cost approximately $1,450. Based on these figures, the cost 
impact of the rework (by machine shop rework of the components) on U.S. 
operators is estimated to be $5,650 per airplane.
    The cost impact figures discussed above are 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.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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

    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

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

97-01-10  Boeing: Amendment 39-9881. Docket 96-NM-145-AD.

    Applicability: Model 737-100 and -200 series airplanes; as 
listed in Boeing 737 Service Bulletin 27-1033, dated February 13, 
1970; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an unexpected, significant control upset due to 
mechanical interference

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within the lateral control system transfer mechanism, which could 
result in reduced travel of a control wheel and above normal control 
wheel forces during a jam override, accomplish the following:
    (a) Within 18 months after the effective date of this AD: 
Accomplish the requirements of either paragraph (a)(1) or (a)(2) of 
this AD, in accordance with Boeing 737 Service Bulletin 27-1033, 
dated February 13, 1970.
    (1) Replace the aileron control transfer mechanism, part number 
(P/N)
    65-54200-4 or -5, with a new modified mechanism in accordance 
with Procedure II of the Accomplishment Instructions of the service 
bulletin.
    (b) As of the effective date of this AD, no person shall install 
an aileron control transfer mechanism having P/N 65-54200-4 or -5 
unless it has been reworked in accordance with the requirements of 
paragraph (a)(2) of this AD.
    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (d) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (e) The replacement and rework shall be done in accordance with 
Boeing 737 Service Bulletin 27-1033, dated February 13, 1970. 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. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    1(f) This amendment becomes effective on February 19, 1997.

    Issued in Renton, Washington, on January 3, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-537 Filed 1-14-97; 8:45 am]
BILLING CODE 4910-13-U