[Federal Register Volume 61, Number 13 (Friday, January 19, 1996)]
[Proposed Rules]
[Pages 1291-1294]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-474]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-138-AD]


Airworthiness Directives; Boeing Model 737-300, -400, and -500 
Series Airplanes Equipped With Air Cruisers Evacuation Slides

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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[[Page 1292]]


SUMMARY: This document proposes the supersedure of two existing 
airworthiness directives (AD), applicable to certain Boeing Model 737 
series airplanes, that currently requires modification of the packing 
and slide containers of the escape slide, and repetitive inspections of 
the velcro girt retaining straps at the forward door of the escape 
slides. The existing AD's were prompted by reports of slide girt 
material interfering with the girt bar stowage brackets during door 
opening. This action would require a new terminating modification, 
which would constitute terminating action for the repetitive inspection 
requirements. The actions specified by the proposed AD are intended to 
prevent failure or interference of opening of the forward doors, which 
could delay or impede the evacuation of passengers during an emergency.

DATES: Comments must be received by March 11, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-138-AD, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9 a.m. and 3 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Air Cruisers Company, P.O. Box 180, Belmar, New Jersey 
07719-0180; and 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: Roy Boffo, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, Washington; telephone (206) 227-2780; 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-138-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-138-AD, 1601 Lind Avenue SW., Renton, Washington 
98055-4056.

Discussion

    On March 21, 1988, the FAA issued AD 88-07-07, amendment 39-5884 
(53 FR 9864, March 28, 1988), applicable to certain Boeing Model 737-
300 series airplanes, to require modification of the packing and slide 
containers of the escape slide. (This modification has been 
accomplished on Model 737-400 and -500 series airplanes during 
production, in accordance with Production Revision Report 34388.) That 
action was prompted by reports of slide girt material interfering with 
the girt bar stowage brackets during door opening, arresting the door 
opening motion. The requirements of that AD are intended to prevent 
failure or interference of opening of the forward doors during an 
emergency evacuation.
    On October 31, 1991, the FAA issued AD 91-24-04, amendment 39-8090 
(56 FR 57588, November 13, 1991), applicable to certain Boeing Model 
737-300, -400, and -500 series airplanes, equipped with certain Air 
Cruisers forward door escape slides that had been modified in 
accordance with AD 88-07-07. That AD requires repetitive inspections of 
the velcro girt retaining straps at the forward door escape slides. 
That action was prompted by reports of incorrectly routed and 
unserviceable slides or jammed doors during an emergency evacuation. 
The requirements of that AD are intended to prevent a jammed door or an 
escape slide deployed in an unusable position during an emergency 
evacuation.
    Since the issuance of those AD's, the FAA has reviewed and approved 
Air Cruisers Company Service Bulletin S.B. 103-25-19, dated March 25, 
1992, which describes procedures for modification of the escape slide 
girts. This modification involves removing the existing girt; bonding 
on the girt attachments; installing a detachable girt; rigging a 
painter/mooring line; and bonding a placard to slide assembly and 
reidentifying it. This modification will improve the operation of the 
escape slide of the forward entry and service doors. Accomplishment of 
this modification eliminates the need for the repetitive inspections of 
the velcro girt retaining straps at the forward door escape slides 
(currently required by AD 91-24-04). Further, the FAA finds that 
accomplishment of this modification will positively address the unsafe 
condition addressed by the two existing AD's.
    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 supersede AD 88-07-07 to continue to require 
modification of the escape slide packing and slide containers. The 
proposed AD would also supersede AD 91-24-04 to continue to require 
repetitive inspections of the velcro girt retaining straps at the 
forward door of the escape slides. Additionally, the proposed AD would 
require modification of the escape slide girts, which would constitute 
terminating action for the repetitive inspection requirements.
    The FAA has determined that long term continued operational safety 
will be better assured by modification or design change to remove the 
source of the problem, rather than by repetitive inspections. Long term 
inspections may not be providing the degree of safety assurance 
necessary for the transport airplane fleet. This, coupled with a better 
understanding of the human factors associated with numerous repetitive 
inspections, has led the FAA to consider placing less emphasis on 
special procedures and more emphasis on design improvements. The 
proposed modification requirement is in consonance with these 
considerations.
    There are approximately 1,572 Model 737-300, -400, and -500 series 
airplanes, equipped with Air Cruisers forward door escape slide of the 
affected design in the worldwide fleet. The FAA estimates that 663 
airplanes of U.S. registry would be affected by this proposed AD.

[[Page 1293]]

    The actions that are currently required by AD 88-07-07 take 
approximately 9 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts cost approximately $76 
per airplane. Based on these figures, the cost impact on U.S. operators 
(175 airplanes) of the actions currently required is estimated to be 
$107,800, or $616 per airplane.
    The actions that are currently required by AD 91-24-04 take 
approximately 1 work hour per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact on U.S. operators (439 airplanes) of the actions currently 
required is estimated to be $26,340, or $60 per airplane, per 
inspection cycle.
    The modification that is proposed in this new AD action would take 
approximately 6 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $1,800 per airplane. Based on these figures, the cost 
impact on U.S. operators of the new proposed modification requirements 
of this AD is estimated to be $1,432,080, or $2,160 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or 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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendments 39-5884 (53 FR 
9864, March 28, 1988) and 39-8090 (56 FR 57588, November 13, 1991), and 
by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 95-NM-138-AD. Supersedes AD 88-07-07, amendment 39-
5884; and AD 91-24-04, amendment 39-8090.
    Applicability: Model 737-300, -400, and -500 series airplanes, 
line numbers up to and including 2211; equipped with Air Cruisers 
forward door escape slides as listed in Air Cruisers Company Service 
Bulletin S.B. 103-25-19, dated March 25, 1992; 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 use the authority 
provided in paragraph (d) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure or interference of opening of the forward doors, 
which could delay or impede the evacuation of passengers during an 
emergency, accomplish the following:
    (a) Within 30 days after December 17, 1991 (the effective date 
of 91-24-04, amendment 39-8090), establish operating procedures, 
approved by the FAA Principal Maintenance Inspector (PMI), for the 
forward doors to include the requirements specified in paragraphs 
(a)(1), (a)(2), and (a)(3) of this AD; and thereafter, comply with 
those procedures until the modification required by paragraph (c) of 
this AD is accomplished. The procedures required by paragraphs 
(a)(1) and (a)(2) of this AD must be accomplished by qualified and 
trained mechanics. The procedures required by paragraph (a)(3) may 
be accomplished by qualified and trained members of the flightcrew 
or cabin crew. The training program to implement the procedures 
required by this paragraph must be approved by the FAA PMI. Methods 
for documentation of compliance with the following procedures must 
be approved by the FAA PMI.
    (1) Prior to the next flight after December 17, 1991 (the 
effective date of AD 91-24-04, amendment 39-8090), and thereafter at 
intervals not to exceed 200 flight hours, inspect the condition of 
the girt retaining straps at the forward doors.
    (2) Prior to further flight after December 17, 1991 (the 
effective date of 91-24-04, amendment 39-8090), replace worn or aged 
velcro whose grip strength will no longer hold the girt retaining 
straps in position.
    (3) Prior to the next flight after December 17, 1991 (the 
effective date of 91-24-04, amendment 39-8090), and thereafter prior 
to each flight, inspect the routing of the girt retaining straps at 
the forward doors, and reroute straps that are found not to be 
routed in accordance with the placarded instructions installed in 
accordance with AD 88-07-07, amendment 39-5885, on the inboard face 
of the slide compartment.
    (b) For Model 737-300 series airplanes: Within 6 months after 
May 9, 1988 (the effective date of AD 88-07-07, amendment 39-5885), 
modify the escape slide packing and slide containers in accordance 
with Boeing Alert Service Bulletin 737-25A1221, dated December 17, 
1987, or Revision 1, dated June 2, 1988. This modification must be 
accomplished prior to or in conjunction with accomplishment of the 
requirements of paragraph (c) of this AD.
    (c) Within 36 months after the effective date of this AD, modify 
the escape slide girts in accordance with Air Cruisers Company 
Service Bulletin S.B. 103-25-19, dated March 25, 1992. 
Accomplishment of the modification constitutes terminating action 
for the repetitive inspections required by paragraph (a) of this AD.
    (d) 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.

    (e) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199

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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 January 5, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-474 Filed 1-18-96; 8:45 am]
BILLING CODE 4910-13-U