[Federal Register Volume 62, Number 186 (Thursday, September 25, 1997)]
[Proposed Rules]
[Pages 50263-50264]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-25415]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-54-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200 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 757-200 
series airplanes. This proposal would require the application of a 
sealant, secondary fuel barrier, and corrosion-inhibiting compound to 
certain portions of the wing center section. This proposal is prompted 
by reports indicating that, during manufacture, the secondary fuel 
barrier was not applied to certain portions of the wing center section. 
The actions specified by the proposed AD are intended to prevent 
leakage of fuel through the fasteners, sealant, or structural cracks in 
the center section structure, which could result in fuel or fuel vapors 
entering the cargo or passenger compartment of the airplane.

DATES: Comments must be received by November 5, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-54-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: Kathrine Rask, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue SW., Renton, Washington; telephone (425) 227-
1547; 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 97-NM-54-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-103, Attention: Rules 
Docket No. 97-NM-54-AD, 1601 Lind Avenue SW., Renton, Washington 98055-
4056.

Discussion

    The FAA has received reports indicating that, during manufacture, 
the secondary fuel barrier was not applied on the outboard corners of 
the front spar of the wing center section on certain Boeing Model 757-
200 series airplanes. The secondary fuel barrier is applied to areas of 
the wing center section that are exposed to cabin pressure. If the 
secondary barrier is not applied, fuel could leak through the 
fasteners, sealant, or structural cracks in the center section 
structure, which could result in fuel or fuel vapors entering the cargo 
or passenger compartment of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 757-57-
0053, dated February 6, 1997, which describes procedures for the 
application of a sealant, secondary fuel barrier, and corrosion-
inhibiting compound to areas on the front spar of the wing center 
section. Accomplishment of this application will ensure that any fuel 
leaks through the tank structure do not enter the cargo or passenger 
compartments of the airplane.

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 the application of a sealant,

[[Page 50264]]

secondary fuel barrier, and corrosion-inhibiting compound to areas on 
the front spar of the wing center section. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.

Cost Impact

    There are approximately 724 Boeing Model 757-200 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
463 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 $101,860, 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 97-NM-54-AD.

    Applicability: Model 757-200 series airplanes, line numbers 1 
through 724 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 leakage of fuel through the fasteners, sealant, or 
structural cracks in the center section structure, which could 
result in fuel or fuel vapors entering into the cargo or passenger 
compartment of the airplane, accomplish the following:
    (a) Within 18 months after the effective date of this AD, apply 
sealant, secondary fuel barrier, and corrosion-inhibiting compound 
to areas on the front spar of the wing center section, in accordance 
with Figure 3 of Boeing Service Bulletin 757-57-0053, dated February 
6, 1997.
    (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.

    (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 September 19, 1997.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-25415 Filed 9-24-97; 8:45 am]
BILLING CODE 4910-13-U