[Federal Register Volume 67, Number 8 (Friday, January 11, 2002)]
[Proposed Rules]
[Pages 1419-1420]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-842]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-251-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM); Extension of the comment 
period.

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SUMMARY: This document extends the period for public comment on the 
above-referenced NPRM that proposes the supersedure of two existing 
airworthiness directives (AD), applicable to certain Boeing Model 737 
series airplanes. The NPRM proposes to require installation of a new 
rudder control system and changes to the adjacent systems to 
accommodate that new rudder control system. This proposal is prompted 
by FAA determinations that the existing system design architecture is 
unsafe due to inherent failure modes, including single-jam modes and 
certain latent failures or jams, which, when combined with a second 
failure or jam, could cause an uncommanded rudder hardover event and 
consequent loss of control of the airplane. Additionally, the current 
rudder operational procedure is not effective throughout the entire 
flight envelope. This extension of the comment period is necessary to 
assure that all interested persons have ample opportunity to present 
their views on the proposed requirements of the NPRM.

DATES: Comments must be received by February 14, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-251-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 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-251-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 for Windows or 
ASCII text.

FOR FURTHER INFORMATION CONTACT: Kenneth W. Frey, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (425) 227-2673; 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:

[[Page 1420]]

     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.
     For each issue, state what specific change to the proposed 
AD is being requested.
     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-251-AD.'' The postcard will be date stamped 
and returned to the commenter.

Events Leading to This Extension of the Comment Period

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to certain Boeing Model 
737 series airplanes was published as a notice of proposed rulemaking 
(NPRM) in the Federal Register on November 6, 2001(66 FR 56783). The 
NPRM proposed to require installation of a new rudder control system 
and changes to the adjacent systems to accommodate that new rudder 
control system.
    The FAA has received a request from the manufacturer, Boeing, to 
extend the comment period of the NPRM by 30 days. Boeing requests the 
extension because the NPRM would encompass holidays during November and 
December, which would significantly decrease the number of working days 
necessary to develop responses to the comments. Further, during a 
Boeing Critical Design Review (CDR), held on December 4, 2001, the CDR 
team provided information to the operators to enable them to assess the 
impact of the NPRM on their operations. Because the CDR was held after 
the NPRM was issued, operators have less time to assess the 
requirements of the proposed rule. In addition, Boeing states that the 
proposed action of the NPRM is a complex retrofit requirement with many 
aspects to consider.

The FAA's Determination

    The FAA has considered Boeing's request and finds it appropriate to 
extend the comment period to give all interested persons additional 
time to examine the proposed requirements of the NPRM and submit 
comments. After evaluating the comments provided in Boeing Letter B-
H210-01-0400, dated November 30, 2001, we have determined that 
extending the comment period by 30 days will not compromise the safety 
of these airplanes.

The Extension

    The comment period for Docket No. 2001-NM-251-AD is hereby extended 
to February 14, 2002.
    Since no portion of the NPRM or other regulatory information has 
been changed, the entire NPRM is not being republished.

    Issued in Renton, Washington, on January 8, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate,Aircraft Certification Service.
[FR Doc. 02-842 Filed 1-10-02; 8:45 am]
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