[Federal Register Volume 64, Number 137 (Monday, July 19, 1999)]
[Proposed Rules]
[Pages 38603-38605]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18368]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-378-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 727 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain Boeing Model 727 series
airplanes. This proposal would require modification of the pressure web
of the nose landing gear wheel well. This proposal is prompted by
reports of fatigue cracks in the pressure web of the nose landing gear
wheel well. The actions specified by the proposed AD are intended to
prevent cracking of the pressure web of the nose landing gear wheel
well, which could result in loss of airplane pressurization.
DATES: Comments must be received by September 2, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-378-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Walt Sippel, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall
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identify the Rules Docket number and be submitted in triplicate to the
address specified above. All communications received on or before the
closing date for comments, specified above, will be considered before
taking action on the proposed rule. The proposals contained in this
notice may be changed in light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 98-NM-378-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 98-NM-378-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
In 1990, the FAA issued AD 90-06-09, amendment 39-6488 (55 FR 8370,
March 7, 1990), which required incorporation of certain structural
modifications on certain Boeing Model 727 series airplanes, in
accordance with Boeing Document No. D6-54860, Revision C, dated
December 11, 1989, ``Aging Airplane Service Bulletin Structural
Modification Program--Model 727.'' One of those modifications was
installation of reinforcement straps and stiffeners on the sidewall,
top, and forward bulkhead panels of the pressure web of the nose
landing gear wheel well. That AD was prompted in part by reports of
fatigue cracks in the pressure web of the nose landing gear wheel well.
Since the issuance of AD 90-06-09, the airplane manufacturer has
notified the FAA that certain Model 727 series airplanes were
inadvertently not included in the effectivity listing of Boeing
Document No. D6-54860, Revision C, and hence, were also omitted from
the applicability of that AD. Because such cracking has been attributed
to fatigue, those airplanes may also be subject to the same unsafe
condition. Cracking in the pressure web of the nose landing gear wheel
well could result in loss of airplane pressurization.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 727-53-
0145, Revision 1, dated December 7, 1989, which describes procedures
for repetitive inspections of the sidewall, top, and forward bulkhead
panels of the pressure web of the nose landing gear wheel well, and
repair, if necessary. The service bulletin also describes procedures
for a modification that involves installation of reinforcement straps
and stiffeners on the sidewall, top, and forward bulkhead panels of the
pressure web of the nose landing gear wheel well. Such installation
would eliminate the need for the repetitive inspections in that area.
Accomplishment of the modification specified in the service bulletin is
intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require accomplishment of the actions specified in
the service bulletin described previously, except as discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that, although the service bulletin describes
procedures for repetitive inspections of the pressure web of the nose
landing gear wheel well, and repair, if necessary, this AD proposes to
mandate only the modification of the pressure web of the nose landing
gear wheel well. The FAA has determined that long-term continued
operational safety will be better assured by design changes to prevent
cracks, rather than repetitive inspections. Long-term inspections may
not provide the degree of safety assurance necessary for the transport
airplane fleet. This, coupled with a better understanding of the human
factors associated with numerous continual inspections, has led the FAA
to consider placing less emphasis on inspections and more emphasis on
design improvements. The decision to propose mandating only the
modification and not the repetitive inspections described previously is
in consonance with these conditions.
Operators should also note that this proposed AD would be
applicable to airplanes not included in the effectivity listing of the
service bulletin. AD 90-06-09 mandated the modification of the pressure
web of the nose landing gear wheel well for airplanes listed in Boeing
Document No. D6-54860, Revision C, dated December 11, 1989, ``Aging
Airplane Service Bulletin Structural Modification Program--Model 727.''
The airplanes to which this proposed AD would be applicable are
included in the effectivity listing of Revision H, dated May 9, 1996,
of that document.
Cost Impact
There are approximately 24 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 13 airplanes of U.S. registry
would be affected by this proposed AD, that it would take approximately
82 work hours per airplane to accomplish the proposed modification, and
that the average labor rate is $60 per work hour. Required parts would
cost approximately $701 per airplane. Based on these figures, the cost
impact of the proposed AD on U.S. operators is estimated to be $73,073,
or $5,621 per airplane.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have sufficient federalism
implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by
[[Page 38605]]
contacting the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
Boeing: Docket 98-NM-378-AD.
Applicability: Model 727 series airplanes; line numbers 124,
126, 130, 146, 221, 287, 331, 339, 345, 355, 416, 439, 516, 532,
540, 608, 631, 650, 717, 777, 788, 791, 837, and 1087; 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 (b) 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 cracking of the pressure web of the nose landing gear
wheel well, which could result in loss of airplane pressurization,
accomplish the following:
Modification
(a) Prior to the accumulation of 60,000 total flight cycles, or
within 4 years after the effective date of this AD, whichever occurs
later, install reinforcement straps and stiffeners on the sidewall,
top, and forward bulkhead panels of the pressure web of the nose
landing gear wheel well, in accordance with Part II of the
Accomplishment Instructions of Boeing Service Bulletin 727-53-0145,
Revision 1, dated December 7, 1989.
Alternative Methods of Compliance
(b) 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; or in accordance
with data meeting the type certification basis of the airplane
approved by a Boeing Company Designated Engineering Representative
who has been authorized by the Manager, Seattle ACO, to make such
findings. 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
(c) 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.
Issued in Renton, Washington, on July 13, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-18368 Filed 7-16-99; 8:45 am]
BILLING CODE 4910-13-P
