[Federal Register Volume 62, Number 236 (Tuesday, December 9, 1997)]
[Proposed Rules]
[Pages 64779-64780]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-32110]



[[Page 64779]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-65-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 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 747-400 
series airplanes. This proposal would require a one-time inspection of 
the separation between the galley power feeder and static ground 
wiring, and the adjacent passenger oxygen system tubing in the forward 
ceiling area above the door 4 galley; and rerouting of wiring, and 
installing clamps and sleeves, if necessary. This proposal is prompted 
by reports of inadequate clearance between the galley power feeder 
wiring and passenger oxygen system tubing. The actions specified by the 
proposed AD are intended to prevent such inadequate clearance, which 
could result in a fire in the ceiling area above the door 4 galley due 
to chafing of wiring on oxygen system tubing.

DATES: Comments must be received by January 23, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-65-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: Susan Letcher, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (425) 227-2670; 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-65-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-65-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA received reports of inadequate clearance between the galley 
power feeder wiring and the adjacent passenger oxygen system tubing in 
the forward ceiling area above the door 4 galley on a number of Model 
747-400 series airplanes, including one in assembly. Inadequate 
clearance between wiring and oxygen tubing can result in chafing of the 
wiring on the tubing, and resultant electrical arcing, which could 
damage the oxygen tubing. If the damaged tubing is pressurized, oxygen 
could leak in the vicinity of the electrical arcing. This condition, if 
not corrected, could result in a fire in the ceiling area above the 
door 4 galley.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-25A3137, dated March 13, 1997, which describes procedures for a 
one-time inspection of the separation between the galley power feeder 
and static ground wiring, and the adjacent passenger oxygen system 
tubing in the forward ceiling area above the door 4 galley; and 
rerouting of wiring, and installing clamps and sleeves, if necessary, 
to obtain adequate separation.

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 alert service bulletin described previously.

Differences Between the Alert Service Bulletin and This Proposed AD

    The alert service bulletin separates affected airplanes into two 
groups (Groups 1 and 2), and recommends compliance within 90 days and 
18 months, respectively, for those groups. In addition to providing 
oxygen to passengers in the event of an in-flight depressurization, the 
oxygen system on Group 1 airplanes also can provide therapeutic oxygen. 
The oxygen tubing on Group 1 airplanes is always pressurized with 
oxygen because of this therapeutic oxygen feature. The oxygen tubing on 
Group 2 airplanes is only pressurized when the passenger oxygen system 
is activated in the event of depressurization. Chafing of wires on 
pressurized oxygen tubing (i.e., Group 1 airplanes) represents a 
greater fire hazard; therefore, the alert service bulletin recommends 
earlier compliance for that group.
    The manufacturer has advised the FAA that most Group 1 airplanes 
have already voluntarily accomplished the actions specified in the 
alert service bulletin, and no cases of chafing have been found. In 
light of this, the FAA has determined that a compliance time of 18 
months for both Group 1 and Group 2 airplanes will provide an 
acceptable level of safety.

Cost Impact

    There are approximately 452 Boeing Model 747-400 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
36 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

[[Page 64780]]

actions, and that the average labor rate is $60 per work hour. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $4,320, or $120 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-65-AD.

    Applicability: Model 747-400 series airplanes; as listed in 
Boeing Alert Service Bulletin 747-25A3137, dated March 13, 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 
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 chafing of the galley power feeder and static ground 
wiring on passenger oxygen system tubing in the forward ceiling area 
above the Door 4 galley, which could result in a fire, accomplish 
the following:
    (a) Within 18 months after the effective date of this AD: 
Perform a one-time inspection of the separation between the galley 
power feeder and static ground wiring, and the adjacent passenger 
oxygen system tubing in the forward ceiling area above the door 4 
galley, in accordance with Boeing Alert Service Bulletin 747-
25A3137, dated March 13, 1997. If the separation is outside the 
limits specified in the alert service bulletin, prior to further 
flight, reroute the wiring, and install clamps and sleeves in 
accordance with the alert 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 December 2, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-32110 Filed 12-8-97; 8:45 am]
BILLING CODE 4910-13-U