[Federal Register Volume 61, Number 119 (Wednesday, June 19, 1996)]
[Proposed Rules]
[Pages 31061-31063]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-15604]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-106-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 and 737 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 and 737 
series airplanes. This proposal would require replacing the fuel cap 
assembly with a new assembly on the inlet fitting at the inside top of 
the auxiliary fuel tank. The proposal would also require replacing the 
INOP placards with new placards. This proposal is prompted by reports 
that the fuel cap assembly, due to its design, became loose and allowed 
fuel to enter the deactivated auxiliary fuel tanks on in-service 
airplanes. The actions specified by the proposed AD are intended to 
prevent unwanted fuel transferring to the deactivated auxiliary fuel 
tanks, due to the problems associated with a loose fuel cap assembly.

DATES: Comments must be received by July 29, 1996.


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ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-106-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: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-
2686; fax (206) 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 95-NM-106-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. 95-NM-106-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On October 31, 1980, the FAA issued AD 80-02-01 R2, amendment 39-
3969 (45 FR 74467, November 10, 1980), applicable to Boeing Model 727 
series airplanes on which an operative Boeing-designed auxiliary body 
fuel system is installed. In addition, the FAA issued a similar AD 80-
02-02 R2, amendment 39-3970 (45 FR 74467, November 10, 1980), which is 
applicable to Boeing Model 737 series airplanes on which an operative 
Boeing-designed auxiliary body fuel system is installed. Those ADs were 
prompted by reports of loss of fuel from the auxiliary body fuel tank 
due to defective and damaged shrouds. The actions required by those 
AD's are intended to prevent failure of the fuel system and unwanted 
fuel transfer to the auxiliary body fuel tanks.

Events Since Issuance of Previous AD's

    Since issuance of those AD's, the FAA has received reports 
indicating that, on certain Boeing Model 727 series airplanes, the fuel 
cap assembly (which was installed to deactivate the auxiliary fuel 
tanks, in accordance with AD 80-02-01 R2) became loose and allowed fuel 
to enter the tanks. Investigation revealed that, due to incorrect 
procedures that were provided in the relevant service bulletin, the 
safety lockwire of the fuel cap assembly was attached to the cap, 
rather than to the nut. This condition, if not corrected, could allow 
the nut of the fuel cap assembly to back off and the cap to loosen; 
consequently, unwanted fuel could then transfer to the auxiliary fuel 
tanks.
    The fuel cap assembly on certain Model 737 series airplanes is 
identical to that on the affected Model 727 series airplanes. 
Therefore, those Model 737 series airplanes may be subject to this same 
unsafe condition revealed on the Model 727 series airplanes.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
727-28A0062, Revision 5, dated May 4, 1995 (for Model 727 series 
airplanes) and Boeing Alert Service Bulletin 737-28A1032, Revision 2, 
dated May 4, 1995 (for Model 737 series airplanes). For airplanes 
equipped with forward and/or aft auxiliary fuel tanks that have been 
deactivated, these service bulletins contain:
    1. Procedures for replacing the fuel cap assembly having part 
number (P/N) AN929A24 with a new fuel cap assembly having P/N AN929L24 
on the inlet fitting at the inside top of the auxiliary fuel tank; and
    2. procedures for replacing the INOP placards with new placards, 
which state that the fuel indicators for the auxiliary fuel tanks are 
still operational.
    For certain other airplanes listed in these service bulletins, no 
additional work is necessary.

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 replacing the fuel cap assembly with a new 
assembly on the inlet fitting at the inside top of the auxiliary fuel 
tank. The proposed AD also would require replacing the INOP placards 
with new placards; these replacement actions would be required only on 
airplanes on which the auxiliary fuel tank has been deactivated. The 
actions would be required to be accomplished in accordance with the 
service bulletins described previously.

Cost Impact

    There are approximately 211 Boeing Model 727 series airplanes and 
36 Boeing Model 737 series airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 134 Boeing Model 727 series 
airplanes and 25 Boeing Model 737 series airplanes of U.S. registry may 
be affected by this proposed AD, depending on the current configuration 
of the airplanes.
    For Boeing Model 727 series airplanes, the proposed modification 
would take approximately 53 work hours per airplane to accomplish, at 
an average labor rate of $60 per work hour. Required parts would be 
supplied by the manufacturer at no cost to the operators. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $3,180 per airplane.
    For Boeing Model 737 series airplanes, the proposed modification 
would take approximately 18 work hours per airplane to accomplish, at 
an average labor rate of $60 per work hour. Required parts would be 
supplied by the manufacturer at no cost to the operators. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $1,080 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of

[[Page 31063]]

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 95-NM-106-AD.

    Applicability: Model 727 and 737 airplanes equipped with forward 
and/or aft auxiliary fuel tanks that have been deactivated, 
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 the nut of the fuel cap assembly from backing off and 
the cap from loosening, and subsequently, unwanted fuel transferring 
to the auxiliary fuel tanks, accomplish the following:
    (a) Within 6 months after the effective date of this AD, 
accomplish paragraphs (a)(1) and (a)(2) of this AD, in accordance 
with Part IV of the Accomplishment Instructions of Boeing Service 
Bulletin 727-28A0062, Revision 5, dated May 4, 1995 (for Model 727 
series airplanes), or Boeing Service Bulletin 737-28A1032, Revision 
2, dated May 4, 1995 (for Model 737 series airplanes), as 
applicable.
    (1) Replace the fuel cap assembly having part number (P/N) 
AN929A24 with a new fuel cap assembly having P/N AN929L24 on the 
inlet fitting at the inside top of the auxiliary fuel tank, in 
accordance with the applicable service bulletin. And
    (2) Replace the INOP placards with new placards, in accordance 
with the applicable service bulletin.
    (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 June 13, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-15604 Filed 6-18-96; 8:45 am]
BILLING CODE 4910-13-U