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

[Federal Register Volume 65, Number 16 (Tuesday, January 25, 2000)]
[Rules and Regulations]
[Pages 3801-3803]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-1596]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-351-AD; Amendment 39-11521; AD 2000-02-03]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-300, -400, and -500 
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 737-300, -400 and -500 series 
airplanes, that requires replacement, with new parts, of the existing 
actuators or the rod ends on the existing actuators at wing leading 
edge slat positions 1, 2, 5, and 6. This amendment is prompted by 
reports indicating that the rod ends on several leading edge slat 
actuators have fractured. The actions specified by this AD are intended 
to prevent fatigue cracking of the rod ends of the leading edge slat 
actuators, which could result in uncommanded deployment of the wing 
leading edge slat and consequent reduced controllability of the 
airplane.

DATES: Effective February 29, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 29, 2000.

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.

[[Page 3802]]


FOR FURTHER INFORMATION CONTACT: Robert C. Jones, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue 
SW., Renton, Washington 98055-4056; telephone (425) 227-1118; fax (425) 
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 all Boeing Model 737-300, -400 and 
-500 series airplanes was published in the Federal Register on August 
19, 1999 (64 FR 45211). That action proposed to require replacement, 
with new parts, of the existing actuators or the rod ends on the 
existing actuators at wing leading edge slat positions 1, 2, 5, and 6.

Comments

    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

    One commenter supports the proposed rule.

Request To Reference New Revision of Alert Service Bulletin

    One commenter requests that the FAA revise the proposed rule to 
reference Boeing Alert Service Bulletin 737-27A1211, Revision 1, dated 
December 9, 1999, as an appropriate source of service information for 
accomplishment of the actions specified by the proposal. The proposed 
AD referenced the original issue of the alert service bulletin, dated 
November 19, 1998. The commenter states that referencing the revised 
alert service bulletin will minimize the amount of rework and parts 
necessary for airplanes that have received a certain other 
modification.
    The FAA concurs with the commenter's request. The FAA has reviewed 
and approved Boeing Alert Service Bulletin 737-27A1211, Revision 1. The 
instructions contained in Revision 1 of the alert service bulletin are 
substantially similar to those in the original issue of the alert 
service bulletin, but Revision 1 adds references to new part numbers 
and kits that will provide new alternatives for compliance with this 
AD. In addition, as the commenter states, Revision 1 of the alert 
service bulletin provides alternative procedures for accomplishing the 
replacement on airplanes that have received a certain other 
modification. Therefore, paragraph (a) of this final rule has been 
revised to state that replacement of existing actuators or rod ends 
with new parts may be accomplished in accordance with either the 
original issue or Revision 1 of the alert service bulletin.

Explanation of Additional Change

    The SUMMARY section of the preamble of the proposed rule 
incorrectly states that the proposed AD would be applicable to all 
Boeing Model 737-300, -400, and -500 series airplanes. However, the 
applicability statement of the proposal correctly states that the 
proposed AD would be applicable to Boeing Model 737-300, -400, and -500 
series airplanes having line numbers 1001 through 3063 inclusive. 
Accordingly, the SUMMARY section of this final rule has been corrected 
to state that this AD applies to certain Boeing Model 737-300, -400 and 
-500 series airplanes.

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 1,897 Model 737-300, -400, and -500 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 720 airplanes of U.S. registry will be affected by this 
AD.
    Replacement of the leading edge slat actuator with an actuator that 
has a new rod end is one option for compliance with this AD. 
Replacement of the actuators on slat positions 1, 2, 5, and 6 will take 
approximately 3 hours per airplane to accomplish, at an average labor 
rate of $60 per work hour. Required parts will cost approximately 
$32,252 per airplane. Based on these figures, the cost impact of the 
installation of actuators with new rod ends, as provided as one option 
by this AD, on U.S. operators is estimated to be $32,432 per airplane.
    In lieu of installation of an actuator with a new rod end, this AD 
provides an option for replacement of the rod ends on the existing 
actuators. This action will take approximately 4 work hours per 
airplane, at an average labor rate of $60 per work hour. Required parts 
will cost between approximately $5,928 and $21,544 per airplane. Based 
on these figures, the cost impact of the replacement of the rod ends, 
as provided as one option by this AD, on U.S. operators is estimated to 
be between $6,168 and $21,784 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 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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:

2000-02-03  Boeing: Amendment 39-11521. Docket 98-NM-351-AD.

    Applicability: Model 737-300, -400, and -500 series airplanes; 
line numbers 1001

[[Page 3803]]

through 3063 inclusive; certificated in any category.


    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
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 fatigue cracking of the rod ends on the leading edge 
slat actuators, which could result in uncommanded deployment of the 
wing leading edge slat and consequent reduced controllability of the 
airplane, accomplish the following:

Replacement

    (a) Within 24 months after the effective date of this AD: 
Replace the leading edge slat actuator with an actuator that has a 
new rod end, or replace the rod end on the existing slat actuator 
with a new rod end, at slat positions 1, 2, 5, and 6; in accordance 
with the Accomplishment Instructions in Boeing Alert Service 
Bulletin 737-27A1211, dated November 19, 1998, or Revision 1, dated 
December 9, 1999.

Spares

    (b) As of the effective date of this AD, no person shall install 
any part having a part number identified in the ``Existing Part 
Number'' column of Section 2.E. of Boeing Alert Service Bulletin 
737-27A1211, dated November 19, 1998, on any airplane.

Alternative Methods of Compliance

    (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.

Special Flight Permits

    (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.

Incorporation by Reference

    (e) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 737-27A1211, dated November 19, 1998; or Boeing 
Alert Service Bulletin 737-27A1211, Revision 1, dated December 9, 
1999. 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.
    (f) This amendment becomes effective on February 29, 2000.


    Issued in Renton, Washington, on January 18, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-1596 Filed 1-24-00; 8:45 am]
BILLING CODE 4910-13-U

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