[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]
BILLING CODE 4910-13-U
