[Federal Register Volume 66, Number 105 (Thursday, May 31, 2001)]
[Proposed Rules]
[Pages 29514-29516]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-13582]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 66, No. 105 / Thursday, May 31, 2001 / 
Proposed Rules

[[Page 29514]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-44-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).

-----------------------------------------------------------------------

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 initial and repetitive inspections of the elevator tab assembly 
to find any damage or discrepancy; and corrective actions, if 
necessary. This action is necessary to prevent excessive in-flight 
vibrations of the elevator tab, which could lead to loss of the 
elevator tab and consequent loss of controllability of the airplane. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by July 16, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-44-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
<a href="/cdn-cgi/l/email-protection#6e57430f000343001e1c030d0103030b001a2e080f0f40090118"><span class="__cf_email__" data-cfemail="370e1a56595a1a5947455a54585a5a5259437751565619505841">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-44-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.
    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: Nenita Odesa, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2557; 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:
    <bullet> 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.
    <bullet> For each issue, state what specific change to the proposed 
AD is being requested.
    <bullet> 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 2000-NM-44-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. 2000-NM-44-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports indicating high-frequency 
airframe vibrations of the elevator tab on certain Boeing Model 737 
series airplanes during flight. Such vibrations have been attributed to 
excessive free-play of the elevator tab, resulting in severe damage to 
the elevator, elevator tab, and elevator tab control mechanism. Several 
reports indicated that the source of the vibration was an elevator tab 
vibrating due to wear of the hinges and the control system, which 
caused the elevator tab assemblies to come loose. Another report 
indicated incorrect installation of the elevator tab assembly and tab 
control mechanism due to improper maintenance. In one incident, a 
portion of the elevator tab separated from the airplane causing damage 
to the elevator tab, elevator, and horizontal stabilizer. In another 
incident there was severe damage to the airplane's elevator and 
elevator tab assembly. Several incidents resulted in severe structural 
damage to the elevator tab assembly. These conditions, if not 
corrected, could result in loss of the elevator tab and consequent loss 
of controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 737-
55A1070, Revision 1, dated May 10, 2001, including Appendices A, B, and 
C. The inspection procedures specified in this service bulletin are 
listed in the table, below:

[[Page 29515]]



                          Inspection Procedures
------------------------------------------------------------------------
        Work package and action specified                  Figure
------------------------------------------------------------------------
I--Initial detailed visual/free play inspections
 of the following:
    <bullet> Attachment of the elevator tab        3, 4
     assembly at four hinge locations.
    <bullet> Elevator tab trailing edge..........  3, 4
    <bullet> Elevator tab axial..................  3, 4
    <bullet> Elevator tab control mechanism to     5-7
     the horizontal stabilizer, elevator front
     spar, and elevator tab push rods.
    <bullet> Elevator tab push rods to the         5-7
     elevator tab mast fitting/tab rod adjustment
     lock nut.
    <bullet> Elevator tab assembly installation..  8-11
 
        Note: The service bulletin recommends
         scheduling the repetitive inspections to
         coincide with the inspections specified
         in Work Packages II and III.
II--Repetitive free-play inspections of the
 following:
    <bullet> Elevator tab hinges 1 through 4.....  3, 4
    <bullet> Elevator tab trailing edge..........  3, 4
    <bullet> Elevator tab axial..................  3, 4
III--Repetitive free-play inspections of the
 following:
    <bullet> Elevator tab hinges 1 through 4.....  3, 4
    <bullet> Elevator tab trailing edge..........  3, 4
    <bullet> Elevator tab axial..................  3, 4
------------------------------------------------------------------------

    In addition, the service bulletin specifies corrective actions that 
include, among other things, repairing, replacing, reworking; and 
aligning and torqueing certain components. Procedures also specify the 
replacement of any damaged or discrepant part with a new part, or 
repair, as applicable. Discrepancies include loose or missing parts or 
excessive wear.

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, this 
proposed AD is being issued to prevent excessive in-flight airframe 
vibrations of the elevator tab, which could lead to loss of the 
elevator tab and consequent loss of controllability of the airplane. 
This proposed AD requires initial and repetitive inspections of the 
elevator tab assembly to find any damage or discrepancy; and corrective 
actions, if necessary. The proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously, 
except as discussed below.

Difference Between the Service Bulletin and This Proposed AD

    Although the service bulletin uses the term ``check'' for certain 
inspections, this AD uses the term ``inspection.''

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    There are approximately 2,790 Model 737 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 1,080 
airplanes of U.S. registry would be affected by this proposed AD.

------------------------------------------------------------------------
                                           Work
              Work package                hours @  Cost per   Fleet cost
                                          $60/WH   airplane
------------------------------------------------------------------------
I......................................        18    $1,080   $1,166,400
II.....................................         9       540      583,200
III....................................        14       840      907,200
------------------------------------------------------------------------

    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.

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 2000-NM-44-AD.

    Applicability: Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes, line numbers 1 through 3132 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

[[Page 29516]]

owner/operator must request approval for an alternative method of 
compliance per paragraph (d) 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 excessive in-flight vibrations of the elevator tab, 
which could lead to loss of the elevator tab and consequent loss of 
controllability of the airplane, accomplish the following:

Initial/Repetitive Inspections

    (a) Do the applicable initial detailed visual/free play 
inspections of the elevator tab assembly on the left and right sides 
of the airplane to find any damage or discrepancy per Work Package I 
of Boeing Service Bulletin 737-55A1070, Revision 1, dated May 10, 
2001; at the times specified in paragraph (a)(1) or (a)(2) of this 
AD, as applicable. Repeat the free-play inspections after that at 
intervals not to exceed 1,500 flight cycles or 2,000 flight hours, 
whichever comes first, per either Work Package II or Work Package 
III of the service bulletin.

    Note 2: There is a one-way interchangeability between the free-
play inspections specified in Work Packages II and III. The 
repetitive free-play inspections specified in Work Package II can be 
replaced by the repetitive free-play inspections specified in Work 
Package III. But the repetitive free-play inspections specified in 
Work Package III cannot be replaced by the repetitive free-play 
inspections specified in Work Package II.

    (1) For airplanes having less than 4,500 total flight cycles: 
Before the accumulation of 4,500 total flight cycles or within 120 
days after the effective date of this AD, whichever comes later.
    (2) For airplanes having 4,500 or more total flight cycles: Do 
the inspections at the times specified in paragraph (a)(2)(i) or 
(a)(2)(ii), as applicable.
    (i) Within 120 days after the effective date of this AD.
    (ii) If the initial inspections were done before the effective 
date of this AD per Boeing All Operator Telex M-7200-00-00034, dated 
February 15, 2000: Within 1,500 flight cycles or 2,000 flight hours 
after the effective date of this AD, whichever comes later.

    Note 3: Initial inspections done before the effective date of 
this AD per Boeing Alert Service Bulletin 737-55A1070, dated January 
13, 2000, are considered acceptable for compliance with the initial 
inspections required by paragraph (a) of this AD.


    Note 4: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation or assembly to find damage, 
failure or irregularity. Available lighting is normally supplemented 
with a direct source of good lighting at intensity deemed 
appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc. may be used. Surface cleaning and elaborate 
access procedures may be required.''

    (b) Within 4,500 flight cycles or 6,000 flight hours, whichever 
comes first, after doing the initial inspections required by 
paragraph (a) of this AD: Do the free-play inspections of the 
elevator tab assembly on the left and right sides of the airplane to 
find any damage or discrepancy per Work Package III of Boeing 
Service Bulletin 737-55A1070, Revision 1, dated May 10, 2001. Repeat 
the inspections after that at intervals not to exceed 4,500 flight 
cycles or 6,000 flight hours, whichever comes first.

Corrective Actions

    (c) If any damage or discrepancy is found after doing any 
inspection required by paragraphs (a) and (b) of this AD, before 
further flight, do the applicable corrective action per the 
Accomplishment Instructions of Boeing Service Bulletin 737-55A1070, 
Revision 1, dated May 10, 2001.

Alternative Methods of Compliance

    (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. 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (e) Special flight permits may be issued per Secs. 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 May 23, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-13582 Filed 5-30-01; 8:45 am]
BILLING CODE 4910-13-P


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