[Federal Register Volume 59, Number 229 (Wednesday, November 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-29438]


[[Page Unknown]]

[Federal Register: November 30, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-153-AD]

 

Airworthiness Directives; Boeing Model 747-300 and -400 Series 
Airplanes Equipped With BFGoodrich Stretched Upper Deck Evacuation 
Slides, Part Number 7A1323-(  )

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 Boeing Model 747-300 and -400 
series airplanes equipped with certain stretched upper deck evacuation 
slides manufactured by BFGoodrich. This proposal would require 
modification of the slide's main restraint strap, regulator assembly, 
and turbo fan flapper retaining roll pins. This proposal is prompted by 
reports of loss of air pressure and non-inflation of the inflatable 
tubes of the slide due to problems associated with the restraint strap, 
regulator assembly, and turbo fan flapper retaining roll pins. The 
actions specified by the proposed AD are intended to prevent loss of 
air pressure or non-inflation of the inflatable tubes of the slide, 
which could impede the successful evacuation of passengers from the 
airplane during an emergency.

DATES: Comments must be received by January 26, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-153-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 BFGoodrich Company, Aircraft Evacuation Systems, Dept. 
7916, Phoenix , Arizona 85040. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 3229 East Spring Street, Long Beach, 
California.

FOR FURTHER INFORMATION CONTACT: Andrew Gfrerer, Aerospace Engineer, 
Systems & Equipment Branch, ANM-130L, Los Angeles Aircraft 
Certification Office, 3229 East Spring Street, Long Beach, California 
90806-2425; telephone (310) 988-5338; fax (310) 988-5210.

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 94-NM-153-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. 94-NM-153-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of various problems involving 
BFGoodrich stretched upper deck evacuation slides, part number (P/N) 
7A1323-(  ), installed on Boeing Model 747-300 and -400 series 
airplanes:
    There have been several incidents in which the main restraint strap 
of the slide was ingested into one of the turbo fans. This resulted in 
damage to the turbo fan and loss of air pressure in one tube of the 
slide.
    There have been two occurrences of the inflation system regulator 
shutting down due to internal pressure differentials. These incidents 
resulted in non-inflation of one inflatable tube of the slide.
    There has been a report that, during deployment of the slide, the 
turbo fan flapper retaining roll pin broke, allowing the flapper to 
fall out. This resulted in the loss of air pressure in the inflation 
tube. The cause of the broken pin was determined to be the particular 
heat treatment used during manufacture of a certain lot of roll pins.
    Loss of air pressure or non-inflation of the inflation tubes of an 
evacuation slide, if not corrected, could impede the successful 
evacuation of passengers from the airplane during an emergency.
    The FAA has reviewed and approved BFGoodrich Service Bulletin 
7A1323-25-266, Revision 1, dated September 30, 1994, which describes 
procedures for the following modifications:
    1. Relocating the slide's elastic cord ``bungee strap'' attachment 
point and shortening the elastic cord. This will prevent the main 
restraint strap of the slide from being ingested into the turbo fan.
    2. Modifying and making other changes to the regulator assembly, 
such as modifying the regulator cartridge engagement sleeve by the 
addition of drilled holes to prevent the potential for pressure 
differentials that could cause the regulator to shut down; installing a 
revised burst disk to prevent galling when tightening the cartridge 
assembly; changing the type of lubricant to reduce friction forces; and 
installing a new regulator release pin with a baked-on lubricant to 
provide a consistent release force.
    3. Replacing the turbo fan flapper retaining roll pins. This will 
prevent breakage of the pins, thereby preventing the possibility of the 
flapper falling out.
    4. Replacing the original bottle relief valve assembly (P/N 5A2644-
4) with a safety plug assembly (P/N 3A3259-3); and adding a charge 
fitting on the reservoir safety plug assembly to allow for bottle 
charging after the modifications described above have been 
accomplished.
    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 modifying the stretched upper deck evacuation 
slide by relocating the elastic cord ``bungee strap'' attachment point 
and shortening the elastic cord; modifying the regulator assembly; and 
replacing the turbo fan flapper retaining roll pins. The actions would 
be required to be accomplished in accordance with the service bulletin 
described previously.
    Operators should note that this proposed AD is applicable to the 
manufacturer of the airplane model on which the evacuation slides are 
installed, rather than to the manufacturer of the slide. The FAA's 
general policy is that, when an unsafe condition results from the 
installation of an appliance or other item that is installed in only 
one particular make and model of aircraft, the AD is issued so that it 
is applicable to the aircraft, rather than the item. The reason for 
this is simple: Making the AD applicable to the airplane model on which 
the item is installed ensures that operators of those airplanes will be 
notified directly of the unsafe condition and the action required to 
correct it. While it is assumed that an operator will know the models 
of airplanes that it operates, there is a potential that the operator 
will not know or be aware of specific items that are installed on its 
airplanes. Therefore, calling out the airplane model as the subject of 
the AD prevents ``unknowing non-compliance'' on the part of the 
operator.

(The FAA recognizes that there are situations when an unsafe condition 
exists in an item that is installed in many different aircraft. In 
those cases, the FAA considers it impractical to issue AD's against 
each aircraft; in fact, many times, the exact models and numbers of 
aircraft on which the item is installed may not be known. Therefore, in 
those situations, the AD is issued so that it is applicable to the 
item; furthermore, those AD's usually indicate that the item is known 
to be installed on, but not limited to, various aircraft models.)
    There are approximately 900 BFGoodrich stretched upper deck 
evacuation slides of the affected design installed on Boeing Model 747 
series airplanes worldwide. The FAA estimates that 100 of these slides 
are installed on airplanes of U.S. registry that would be affected by 
this proposed AD. It would take approximately 4.5 work hours per slide 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. Required parts would cost approximately $1,402 per 
slide assembly. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $167,200, or $1,672 
per slide.
    The total 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.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 94-NM-153-AD.

    Applicability: Model 747-300 and -400 series airplanes equipped 
with BFGoodrich stretched upper deck evacuation slides, part number 
(P/N) 7A1323-1, -2, -3, -4, -105, -106, -107, -108, -109, or -110; 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of air pressure or non-inflation of the 
inflation tubes of an evacuation slide, which could impede the 
evacuation of passengers from the airplane during an emergency, 
accomplish the following:
    (a) Within 36 months after the effective date of this AD, modify 
the BFGoodrich stretched upper deck evacuation slide, P/N 7A1323-(  
), in accordance with the Accomplishment Instructions of BFGoodrich 
Service Bulletin 7A1323-25-266, Revision 1, dated September 30, 
1994.

    Note 1: Installation of the ``product improvements,'' specified 
in paragraph 2.J. of the Accomplishment Instructions of the service 
bulletin, is not required by this AD.

    (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, Los Angeles 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, Los Angeles ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (c) Special flight permits may be issued in accordance with 
Secs. 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 November 23, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-29438 Filed 11-29-94; 8:45 am]
BILLING CODE 4910-13-U