[Federal Register Volume 64, Number 79 (Monday, April 26, 1999)]
[Rules and Regulations]
[Pages 20146-20148]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-10181]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-37-AD; Amendment 39-11146; AD 99-09-13]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200 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 757-200 series airplanes, that 
requires modifications to the attachment installation of the forward 
lavatory. This amendment is prompted by a stress analysis report 
indicating that the forward lavatory could break free from the upper 
and/or lower attachments during an emergency landing. The actions 
specified by this AD are intended to prevent failure of the attachment 
installation of the forward lavatory during an emergency landing,

[[Page 20147]]

which could result in injury to the crew and passengers.

DATES: Effective June 1, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 1, 1999.

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: Keith Ladderud, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2780; 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 certain Boeing Model 757-200 
series airplanes was published in the Federal Register on May 12, 1998 
(63 FR 26104). That action proposed to require modifications to the 
attachment installation of the forward lavatory.

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.
    One commenter supports the proposed rule, three commenters offer no 
objection to the proposed rule, and one commenter states that the 
proposed rule will not apply to it.

Request to Extend Compliance Time

    One commenter requests that the compliance time for the 
modification requirements be extended from 18 months after the 
effective date of this AD to 24 months or 3,000 flight cycles, 
whichever occurs later. The commenter states that such a schedule would 
coincide with its normal maintenance interval of 24 months or 3,000 
flight cycles. The commenter states that the 18-month compliance time 
would be unnecessarily restrictive and would force it to schedule 
special maintenance visits for some of its airplanes.
    The FAA concurs with the commenter's request to extend the 
compliance time for the modification requirements. However, the FAA 
finds that extending the compliance time for both passenger and 
freighter airplanes from 18 months to 24 months or 3,000 flight cycles 
after the effective date of this AD, whichever occurs first, will not 
adversely affect safety, and will allow the modification to be 
performed at a base during regularly scheduled maintenance. Therefore, 
paragraphs (a) and (b) of this final rule have been revised 
accordingly.

Request to Include A Note About Floor Panels on Freighters

    One of the commenters who expressed no objection to the proposed 
rule requests that a note be inserted in the final rule to clarify that 
the floor panels identified in paragraph (c) of the proposed rule are 
applicable only for freighter airplanes.
    The FAA concurs with the commenter's request. The floor panels 
specified in paragraph (c) of the final rule are not installed on 
passenger airplanes. Therefore, a new NOTE 2 has been inserted into the 
final rule to clarify that the floor panels specified in paragraph (c) 
of the final rule are only installed on freighter airplanes and are not 
used on passenger airplanes.

Request to Revise the Service Bulletin

    One commenter maintains that it is impossible to accomplish the 
instructions specified in Boeing Service Bulletin 757-25-0181, dated 
June 26, 1997, and requests that the service bulletin be revised. The 
commenter states that a certain doubler specified in the service 
bulletin does not always have adequate edge margin on existing 
fasteners. The commenter further states that it fabricated a new 
doubler to accommodate the fastener spacing and, if this condition is 
not addressed in rulemaking action, it will be required to request an 
alternative method of compliance for each airplane that requires a new 
doubler.
    The commenter makes no specific request for a change to the 
proposal. However, Boeing has been advised of the commenter's 
situation, and it will survey other operators to determine whether they 
also have experienced the same short edge margin condition. Boeing will 
revise the service bulletin if necessary.
    The FAA concurs that the commenter will require an alternative 
method of compliance to allow use of a new doubler of its own 
manufacture. Under the provisions of paragraph (d) of this final rule, 
the FAA may consider requests for approval of an alternative method of 
compliance if sufficient data are submitted to substantiate that the 
new doubler would provide an acceptable level of safety. No change to 
the final rule in this regard is necessary.

Request To Increase the Strength of the Lavatory Attachments

    The commenter that supports the proposed rule also requests that 
the strength of the subject lavatory attachments be increased beyond 
the limit required by 14 CFR 25.561. The commenter states that 
survivable accident impacts can exceed the 9g static limit before the 
structure of the airplane breaks up; therefore, the attachments of all 
structures in the cabin of the airplane should be designed to retain 
the structure up to a level where the fuselage frames and skin 
stringers are no longer able to hold together.
    The FAA acknowledges the commenter's concern. However, while there 
may be merit to the commenter's suggestions, this AD is not the 
appropriate context in which to evaluate those suggestions. As the 
commenter states, such an increase in the strength of the lavatory 
attachments would require a change to the 14 CFR 25.561. The FAA has 
determined that an unsafe condition exists, and that the actions 
required by this AD are adequate in order to ensure the continued 
safety of the affected fleet. No change to the final rule in this 
regard is necessary.

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 described 
previously. 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 333 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 225 airplanes of U.S. registry 
will be affected by this AD: 164 passenger airplanes and 61 freighter 
airplanes.
    It will take approximately 10 work hours per passenger airplane to 
accomplish the required modification, at an average labor rate of $60 
per work hour. Required parts will cost approximately $100 per 
airplane. Based on these figures, the cost impact of the required 
modification on U.S. operators is estimated to be $114,800, or $700 per 
passenger airplane.

[[Page 20148]]

    It will take approximately 42 work hours per freighter airplane to 
accomplish the required modification, at an average labor rate of $60 
per work hour. Required parts will be provided by the airplane 
manufacturer at no cost to the operators. Based on these figures, the 
cost impact of this required modification on U.S. operators is 
estimated to be $153,720, or $2,520 per freighter 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:

99-09-13  Boeing: Amendment 39-11146. Docket 98-NM-37-AD.

    Applicability: Model 757-200 series airplanes; as listed in 
Boeing Service Bulletin 757-25-0181, dated June 26, 1997, and Boeing 
Alert Service Bulletin 757-25A0187, dated September 18, 1997; 
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 (d) 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 failure of the attachment installation of the forward 
lavatory during an emergency landing, which could result in injury 
to the crew and passengers, accomplish the following:
    (a) For passenger airplanes identified in Boeing Service 
Bulletin 757-25-0181, dated June 26, 1997: Within 24 months or 3,000 
flight cycles after the effective date of this AD, whichever occurs 
first, install a doubler to the upper attachment installation of the 
forward lavatory in accordance with Boeing Service Bulletin 757-25-
0181, dated June 26, 1997.
    (b) For freighter airplanes identified in Boeing Alert Service 
Bulletin 757-25A0187, dated September 18, 1997: Within 24 months or 
3,000 flight cycles after the effective date of this AD, whichever 
occurs first, install floor panel inserts, a retention fitting 
assembly, and a doubler assembly to the lower attachment 
installation of the forward lavatory, in accordance with Boeing 
Alert Service Bulletin 757-25A0187, dated September 18, 1997.
    (c) As of the effective date of this AD, no person shall install 
a floor panel, part number 141N5410-12 or 141N5410-28, on any 
airplane.

    Note 2: Floor panels having part numbers 141N5410-12 and 
141N5410-28 are only installed on freighter airplanes and are not 
used on passenger airplanes.

    (d) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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.
    (f) The actions shall be done in accordance with Boeing Service 
Bulletin 757-25-0181, dated June 26, 1997, and Boeing Alert Service 
Bulletin 757-25A0187, dated September 18, 1997, as applicable. 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.
    (g) This amendment becomes effective on June 1, 1999.

    Issued in Renton, Washington, on April 19, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-10181 Filed 4-23-99; 8:45 am]
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