[Federal Register Volume 64, Number 134 (Wednesday, July 14, 1999)]
[Proposed Rules]
[Pages 37918-37920]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-17859]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-134-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, and -800 
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 737-600, -
700, and -800 series airplanes. This proposal would require 
installation of a drain at each of the number 2 window frame assemblies 
in the airplane. This proposal is prompted by reports that flight deck 
emergency exits (number 2 windows) were found frozen shut after 
landing. The actions specified by the proposed AD are intended to 
prevent water accumulation in the lower corners of the flight deck 
emergency exits (number 2 windows), which can freeze and prevent the 
exits from being used during an emergency evacuation.

DATES: Comments must be received by August 30, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-134-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: Meghan Gordon, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2207; 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

[[Page 37919]]

statement is made: ``Comments to Docket Number 99-NM-134-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-134-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that flight deck emergency 
exits (number 2 windows) were found frozen shut after landing on Boeing 
Model 737-600, -700, and -800 series airplanes. The design allows water 
to accumulate in the lower corner of the number 2 window, which can 
freeze, preventing the window from opening. This condition, if not 
corrected, could result in the flight deck emergency exits being 
unusable by the flight deck occupants during an emergency evacuation.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 737-56-
1011, dated November 19, 1998, which describes procedures for 
installation of a drain at each of the number 2 window frame assemblies 
in the airplane. Accomplishment of the action specified in the service 
bulletin 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 installation of a drain at each of the number 
2 window frame assemblies. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although the service bulletin does not 
specify a compliance time for accomplishment of installation of a drain 
at each of the number 2 window frame assemblies in the airplane, this 
proposal would require that action to be accomplished within 18 months 
after the effective date of this AD. In developing an appropriate 
compliance time for this proposed AD, the FAA considered the degree of 
urgency associated with addressing the subject unsafe condition, the 
average utilization of the affected fleet, and the time necessary to 
accomplish the proposed actions (approximately 3 hours). In light of 
these factors, the FAA finds a compliance time of 18 months for 
accomplishing the proposed actions 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 144 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 57 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
3 work hours per airplane to accomplish the proposed actions, and that 
the average labor rate is $60 per work hour. Required parts would cost 
approximately $536 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $40,812, 
or $716 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 99-NM-134-AD.

    Applicability: Model 737-600, -700, and -800 series airplanes; 
line numbers 1 through 144 inclusive; 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 water accumulation in the lower corners of the flight 
deck emergency exits (number 2 windows), which can freeze and 
prevent the exits from being used during an emergency evacuation, 
accomplish the following:

Installation

    (a) Within 18 months after the effective date of this AD, 
install a drain at each of the number 2 window frame assemblies in 
the airplane in accordance with Boeing Service Bulletin 737-56-1011, 
dated November 19, 1998.

Alternative Methods of Compliance

    (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

[[Page 37920]]

compliance with this AD, if any, may be obtained from the Seattle 
ACO.

Special Flight Permits

    (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 July 7, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-17859 Filed 7-13-99; 8:45 am]
BILLING CODE 4910-13-U