[Federal Register Volume 64, Number 31 (Wednesday, February 17, 1999)]
[Proposed Rules]
[Pages 7827-7828]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3735]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-06-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 modification of the off-
wing emergency evacuation slide system. This proposal is prompted by 
reports that a certain type of off-wing escape slide aboard several 
airplanes deployed and separated from the airplane during flight. The 
actions specified by the proposed AD are intended to prevent separation 
of the emergency evacuation slide from the airplane, which could result 
in damage to the fuselage and unavailability of an escape slide during 
an emergency evacuation.

DATES: Comments must be received by April 5, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-06-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: Keith Ladderud, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2780; 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 99-NM-06-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. 99-NM-06-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that in-flight deployment 
and separation of the off-wing emergency evacuation slide occurred on 
several Boeing Model 757-200 series airplanes. In each of these 
incidents, the slide compartment door opened, the slide carrier rotated 
out, and the slide deployed. In addition, the deployed slide was torn 
off by the airstream and caused damage to the fuselage located aft of 
the slide compartment. In one incident, the inboard flaps also were 
damaged. These deployments are attributed to the fact that, during 
maintenance, the slide compartment door was not properly latched 
following replacement of the slide. Further analysis revealed that a 
visual inspection of the door latch to verify that the latch is 
fastened is difficult; the aft location of the door sensor may not show 
that the door is not latched; and incorrect installation of the 
lockbase retainer on the door latch tube can prevent locking the door 
in the latched position. These conditions, if not corrected, could 
result in in-flight deployment and separation of the emergency 
evacuation slide from the airplane, damage to the fuselage, and 
unavailability of an escape slide during an emergency evacuation.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 757-25-
0182, Revision 1, dated June 12, 1997; and Boeing Service Bulletin 757-
25-0200, dated January 21, 1999; which describe procedures for 
modification of the left and right off-wing emergency evacuation slide 
systems.
    The modification described in Boeing Service Bulletin 757-25-0182, 
Revision 1, includes replacement of the bearings and lockbase retainer 
in the compartment door latch assembly with new bearings and a new 
lockbase retainer, relocation and adjustment of the sensor target and 
the sensor proximity switch to forward locations on the evacuation 
slide compartment doors, and a functional test following modification.
    The modification described in Boeing Service Bulletin 757-25-0200 
includes installation of a bumper assembly on the off-wing slide 
carrier and installation of new placards in the area of the maintenance 
access door.
    Accomplishment of the actions specified in the service bulletins 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 modification of the off-wing emergency 
evacuation slide system. The actions would be required to be 
accomplished in accordance with the service bulletins described 
previously, except as discussed below.

Difference Between Proposed Rule and Service Bulletins

    Operators should note that, although the service bulletins 
recommend accomplishment of the modification at the next scheduled 
maintenance, or as

[[Page 7828]]

soon as manpower and materials are available, the FAA has determined 
that an 18-month compliance time would address the identified unsafe 
condition in a timely manner. In developing an appropriate compliance 
time for this 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 modification. In light of 
all of these factors, the FAA finds an 18-month compliance time for 
completion of the proposed modification to be warranted, in that it 
represents an appropriate interval of time allowable for affected 
airplanes to continue to operate without compromising safety.

Cost Impact

    There are approximately 497 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 435 airplanes of U.S. registry 
would be affected by this proposed AD.
    For airplanes identified in Boeing Service Bulletin 757-25-0182, 
Revision 1 (301 U.S.-registered airplanes), it would take approximately 
40 work hours per airplane to accomplish the proposed modification of 
the door latch system, at an average labor rate of $60 per work hour. 
Required parts would cost approximately $1,450 per airplane. Based on 
these figures, the cost impact of the proposed modification on U.S. 
operators is estimated to be $1,158,850, or $3,850 per airplane.
    For airplanes identified in Boeing Service Bulletin 757-25-0200 
(435 U.S.-registered airplanes), it would take approximately 4 work 
hours to accomplish the proposed installation of the bumper assembly 
and placards, at an average labor rate of $60 per work hour. Required 
parts would cost approximately $457 per airplane. Based on these 
figures, the cost impact of the proposed installation on U.S. operators 
is estimated to be $303,195, or $697 per airplane.
    The cost impact figures discussed above are 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 99-NM-06-AD.

    Applicability: Model 757-200 series airplanes equipped with off-
wing emergency evacuation slides, as listed in Boeing Service 
Bulletin 757-25-0182, Revision 1, dated June 12, 1997, or Boeing 
Service Bulletin 757-25-0200, dated January 21, 1999; certificated 
in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
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 separation of the emergency evacuation slide from the 
airplane, which could result in damage to the fuselage and 
unavailability of an escape slide during an emergency evacuation, 
accomplish the following:
    (a) Within 18 months after the effective date of this AD: Modify 
the left and right off-wing emergency evacuation slide systems by 
accomplishment of paragraph (a)(1) or (a)(2) of this AD, as 
applicable.
    (1) For airplanes listed in Boeing Service Bulletin 757-25-0182, 
Revision 1, dated June 12, 1997: Modify the door latch system of the 
left and right off-wing emergency evacuation slide systems in 
accordance with the service bulletin.

    Note 2: Modification of the door latch system of the off-wing 
emergency evacuation slide system, prior to the effective date of 
this AD, in accordance with Boeing Service Bulletin 757-25-0182, 
dated October 10, 1996, is considered acceptable for compliance with 
paragraph (a)(1) of this AD.

    (2) For airplanes listed in Boeing Service Bulletin 757-25-0200, 
dated January 21, 1999: Install a bumper assembly on the bottom of 
the left and right off-wing escape slide carriers, and install new 
placards in the area of the maintenance access door, in accordance 
with the 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 3: 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 February 9, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-3735 Filed 2-16-99; 8:45 am]
BILLING CODE 4910-13-U