[Federal Register Volume 68, Number 181 (Thursday, September 18, 2003)]
[Proposed Rules]
[Pages 54684-54686]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-23822]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-156-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 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 737-100, -
200, -200C, -300, -400, and -500 series airplanes. This proposal would 
require replacing the existing screw, nut, and washers that attach the 
latch cable assembly to the latch block assembly of the door mounted 
escape slides, with the new, improved screw, nut, and washers. This 
action is necessary to prevent the latch cable assembly from 
disconnecting from the latch block assembly of the door mounted escape 
slide, which could result in an escape slide not deploying in an 
emergency situation. This action is intended to address the identified 
unsafe condition.

DATES: Comments must be received by November 3, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-156-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. Comments may be submitted via fax to (425) 227-1232. 
Comments

[[Page 54685]]

may also be sent via the Internet using the following address: [email protected]. Comments sent via fax or the Internet must contain 
``Docket No. 2001-NM-156-AD'' in the subject line and need not be 
submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, PO 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, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 917-6435; fax (425) 917-6590.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-156-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. 2001-NM-156-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    An operator reported that the cable on a door mounted escape slide 
had disconnected from the latch block assembly on a Boeing Model 737 
series airplane. Investigation revealed that a production change had 
increased the size of the latch cable loops, which could allow the 
latch cable assembly to disconnect from the latch block assembly. This 
condition, if not corrected, could result in an escape slide not 
deploying in an emergency situation, and consequent reduction in the 
number of exits available in an evacuation.

Related Rulemaking

    On November 29, 1985, the FAA issued AD 85-25-04, amendment 39-5179 
(50 FR 49923, December 6, 1985). That AD required inspecting the escape 
slides and modifying the escape slide containers; and, on certain 
airplanes, the AD required inspecting, modifying escape slide 
installations, and functional testing; in accordance with Boeing 
Service Bulletin 737-25A1182, Revision 2, Parts I, III and IV, dated 
November 12, 1985.
    On February 25, 1986, the FAA issued AD 86-05-04, amendment 39-5249 
(51 FR 7433, March 4, 1986). That AD required installing retaining 
straps for the escape slide covers on the aft doors, in accordance with 
Boeing Service Bulletin 737-25A1182, Revision 2, Part II, dated 
November 12, 1985.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Special Attention Service 
Bulletin 737-25-1434, dated March 22, 2001, which describes procedures 
for replacing the existing screw, nut, and washers that attach the 
latch cable assembly to the latch block assembly of the door mounted 
escape slides, with the new, improved screw, nut, and washers. 
Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.
    The service bulletin also specifies installation of the double loop 
escape slide latch cable assembly as described in Boeing Service 
Bulletin 737-25A1182, dated September 18, 1985, as a concurrent 
requirement. (See ``Related Rulemaking'' above.)

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 service bulletin described previously, except as described below.

Differences Between Service Bulletin and Proposed Rule

    Although the service bulletin recommends accomplishing the 
replacement ``at the next scheduled maintenance period when manpower, 
materials, and facilities are available,'' the FAA has determined that 
such an imprecise compliance time would not address the identified 
unsafe condition in a timely manner. In developing an appropriate 
compliance time for this proposed action, 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 
replacement. In light of all of these factors, the FAA finds that a 
compliance time of 18 months for completing the proposed actions to be 
warranted, in that it represents an appropriate interval of time for 
affected airplanes to continue to operate without compromising safety.

Changes to 14 CFR Part 39/Effect on the Proposed AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance (AMOCs). Because we have now included this material in part 
39, only the office authorized to approve AMOCs is identified in each 
individual AD.

Change to Labor Rate Estimate

    We have reviewed the figures we have used over the past several 
years to calculate AD costs to operators. To account for various 
inflationary costs in the airline industry, we find it necessary

[[Page 54686]]

to increase the labor rate used in these calculations from $60 per work 
hour to $65 per work hour. The cost impact information, below, reflects 
this increase in the specified hourly labor rate.

Cost Impact

    There are approximately 2,919 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 1,129 airplanes of U.S. 
registry would be affected by this proposed AD. The FAA estimates that 
it would take approximately 2 work hours for each airplane specified as 
Group 1 in the referenced service bulletin, and approximately 1 work 
hour for each airplane specified as Group 2 in the referenced service 
bulletin, to accomplish the proposed actions; the average labor rate is 
estimated to be $65 per work hour. Parts and materials are standard and 
are to be supplied by the operator. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $130 per 
Group 1 airplane, and $65 per Group 2 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 proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions. The manufacturer may 
cover the cost of replacement parts associated with this proposed AD, 
subject to warranty conditions. Manufacturer warranty remedies may also 
be available for labor costs associated with this proposed AD. As a 
result, the costs attributable to the proposed AD may be less than 
stated above.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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 2001-NM-156-AD.

    Applicability: Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes, as listed in Boeing Service Bulletin 737-25-1434, 
dated March 22, 2001; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the latch cable assembly from disconnecting from the 
latch block assembly of the door mounted escape slides, which could 
result in an escape slide not deploying in an emergency situation, 
accomplish the following:

Replacement

    (a) Within 18 months after the effective date of this AD, 
replace the existing screw, nut, and washers that attach the latch 
cable assembly to the latch block assembly of the door mounted 
escape slides, with the new, improved screw, nut, and washers; per 
the Work Instructions of Boeing Service Bulletin 737-25-1434, dated 
March 22, 2001.

Parts Installation

    (b) As of the effective date of this AD, no person may install a 
nut, part number (P/N) BACN10R10L, that was removed from any 
airplane; or install a screw, P/N NAS623-3-8; on any airplane.

Alternative Methods of Compliance

    (c)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, is authorized to approve 
alternative methods of compliance (AMOC) for this AD.
    (2) An AMOC that provides an acceptable level of safety may be 
used for repair of the latch cable assembly and the latch block 
assembly for the door mounted escape slide, if it is approved by a 
Boeing Company Designated Engineering Representative (DER) who has 
been authorized by the Manager, Seattle ACO, to make such findings.


    Issued in Renton, Washington, on September 11, 2003.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-23822 Filed 9-17-03; 8:45 am]
BILLING CODE 4910-13-P