[Federal Register Volume 64, Number 136 (Friday, July 16, 1999)]
[Proposed Rules]
[Pages 38382-38383]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18201]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-374-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 777-200 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 777-200
series airplanes. This proposal would require the application of
sealant to the front spar and upper surface of the wing center section
to ensure the integrity of the secondary fuel barrier. This proposal is
prompted by reports from the airplane manufacturer that the sealant was
inadvertently not applied to portions of the wing center section on
certain Boeing Model 777-200 series airplanes. The actions specified by
the proposed AD are intended to prevent fuel or fuel vapors from
entering the cargo and passenger compartments in the event of a failure
of the primary seal or development of a crack in the wing center
section structure. Leakage of fuel or fuel vapors into the cargo and
passenger compartments could be hazardous to personnel, and could cause
a fire in those compartments.
DATES: Comments must be received by August 30, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-374-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: Larry Reising, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2683; 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 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-374-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-374-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received a report that, due to an error during airplane
manufacture, the sealant that serves as a secondary fuel barrier may
not have been applied to the front spar and upper surface of the wing
center section on certain Boeing Model 777-200 series airplanes. This
condition, if not corrected, could permit fuel or fuel vapors to enter
the passenger and cargo compartments of the airplane if there is a
failure of the primary seal or a crack develops in the center section
structure. Leakage of fuel or fuel vapors into the cargo and passenger
compartments could be hazardous to personnel, and could cause a fire in
those compartments.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 777-57-
0033, dated March 26, 1998, which describes procedures for accessing
the overwing stub beams on the left and right sides of the airplane,
and for application of a sealant to the front spar and upper surface of
the wing center section to ensure the integrity of the secondary fuel
barrier. Accomplishment of the actions 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 application of sealant to the front spar and
upper surface of the wing center section to ensure the integrity of the
secondary fuel barrier. These actions
[[Page 38383]]
would be required to be accomplished in accordance with the service
bulletin described previously, except as discussed below.
Differences Between the Proposed Rule and the Service Bulletin
Operators should note that, although the service bulletin
recommends accomplishment of the application of sealant prior to the
accumulation of 4,000 total flight cycles or within 750 days (after
receipt of the service bulletin), whichever occurs earlier, this
proposed AD would require the application of sealant within 24 months
after the effective date of this AD. In developing an appropriate
compliance time for this proposed AD, the FAA considered not only the
manufacturer's recommendation, but the degree of urgency associated
with addressing the subject unsafe condition, the average utilization
of the affected fleet, and the time necessary to perform the actions
(two hours). In light of all of these factors, the FAA finds a
compliance time of 24 months after the effective date of this AD for
accomplishing the proposed actions to be warranted, in that it
represents an appropriate interval of time allowable for affected
airplanes to continue to operate without compromising safety. The FAA
also finds that such a compliance time will provide operators with
approximately the same amount of time to accomplish the proposed
actions as what was specified in the service bulletin.
Cost Impact
There are approximately 37 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 8 airplanes of U.S. registry
would be affected by this proposed AD, that it would take approximately
2 work hours per airplane to accomplish the proposed actions, and that
the average labor rate is $60 per work hour. Required parts would cost
approximately $100 per airplane. Based on these figures, the cost
impact of the proposed AD on U.S. operators is estimated to be $1,760,
or $220 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 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-374-AD.
Applicability: All Model 777-200 series airplanes, line numbers
41 through 91 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
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 (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 fuel or fuel vapors from entering the passenger and
cargo compartments of the airplane in the event of a failure of the
primary seal or development of a crack in the wing center section
structure, accomplish the following:
Corrective Actions
(a) Within 24 months after the effective date of this AD, apply
sealant to the front spar and upper surface of the wing center
section under the overwing stub beams on the left and right sides of
the airplane, in accordance with Boeing Service Bulletin 777-57-
0033, dated March 26, 1998.
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. 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
Sec. 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 12, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-18201 Filed 7-15-99; 8:45 am]
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