[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
