[Federal Register Volume 66, Number 43 (Monday, March 5, 2001)]
[Rules and Regulations]
[Pages 13229-13232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-4761]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-13-AD; Amendment 39-12127; AD 2001-04-08]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -800, and -
700C Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 737-600, -700, -800, and -700C 
series airplanes. This action requires initial and repetitive 
inspections of the elevator tab assembly to detect 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 reduced 
controllability of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Effective March 20, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 20, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before May 4, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-13-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-13-AD'' in the

[[Page 13230]]

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 this AD 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; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2028; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received numerous reports of 
excessive in-flight vibrations of the elevator tab on Model 737-600, -
700, and -800 series airplanes. These vibration events have been 
attributed to loose or missing components, excessive wear, or excessive 
freeplay of the tab. Elevator tab vibrations can result from wear to 
the elevator tab hinges and components of the elevator tab control 
system. Such wear can cause the elevator tab assemblies to become 
loose. Increased exposure to spoiler buffeting can cause premature wear 
to the elevator tab components. Continued operation of these airplanes 
in such conditions could lead to loss of the elevator tab and reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-55A1072, Revision 1, including Appendix A, dated January 11, 2001. 
The inspection procedures specified in this service bulletin are listed 
in Table 1:

                     Table 1.--Inspection Procedures
------------------------------------------------------------------------
               Work package and action specified                 Figure
------------------------------------------------------------------------
I--Initial and repetitive detailed visual inspections of the
 following:
     Elevator tab aerodynamic surfaces................       1.
     Attachment of the elevator tab assembly at four         1.
     hinge locations..........................................
     Attachment of the elevator tab control rods to          1.
     the elevator tab mast fitting............................
    Note: The service bulletin recommends scheduling the
     repetitive inspections to coincide with the inspections
     specified in Work Packages II and III.
II--One-time free-play inspections of the following:
     Elevator tab hinges 1 through 4..................       2.
     Elevator tab lug assembly of all four elevator          2.
     tab hinges...............................................
     Elevator tab trailing edge.......................       2.
     Elevator tab axial...............................       2.
     Elevator tab control mechanism to the horizontal        3.
     stabilizer, elevator front spar, and elevator tab control
     rods.....................................................
     Elevator tab control rods to the elevator tab           3.
     mast fitting/tab rod adjustment lock nut.................
III--Repetitive free-play inspections of the following:
     Elevator tab hinge (all four elevator tab hinges)       2.
     Elevator tab lug assembly (hinge 1 of the               2.
     elevator tab)............................................
     Elevator tab trailing edge.......................       2.
     Elevator tab axial...............................       2.
------------------------------------------------------------------------

    In addition, the service bulletin specifies corrective actions that 
include, among other things, follow-on inspections; replacing, 
reworking, repairing, and lubricating parts; applying inspection putty; 
cleaning; and aligning and torqueing 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.
    The elevator tab assembly on Model 737-700C series airplanes is 
identical to those installed on Model 737-600, -700, and -800 series 
airplanes. Therefore, Model 737-700C series airplanes may be subject to 
the same unsafe condition revealed on Model 737-600, -700, and -800 
series airplanes. Model 737-700C series airplanes are included in 
paragraph 1.A. (Effectivity) of the service bulletin.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this 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 reduced 
controllability of the airplane. This AD requires initial and 
repetitive inspections of the elevator tab assembly to detect any 
damage or discrepancy; and corrective actions, if necessary.
    The FAA has determined that the actions required by this AD are 
necessary to ensure the integrity of the elevator tab and the continued 
safe operation of the Model 737 next-generation fleet, until a newly 
designed elevator tab can be retrofitted onto the affected airplanes.
    This AD requires doing the actions specified in the service 
bulletin described previously, except as discussed below.

Differences

    Operators should note the following differences between the service 
bulletin and this AD:
     Although the service bulletin recommends doing the one-
time free-play inspections specified in Work Package II, ``within 120 
days from date of service bulletin, or at 750 total flight cycles, 
whichever is later,'' the FAA has determined that an interval of 120 
days would not address the identified unsafe condition in a timely 
manner. In developing an appropriate compliance time for this AD, 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 one-time inspections (13 hours). In light of 
these factors, we find a 90-day compliance time for completing the 
required actions to be warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety. In addition, it is necessary to 
require these actions ``after the effective date of this AD'' rather 
than ``from date of the service bulletin.'' These changes are included 
in paragraph (a) of this AD, accordingly.
     Although the service bulletin uses the term ``check'' for 
certain inspections, this AD uses the term ``inspection'' instead.
     Although the service bulletin specifies that the 
manufacturer may be contacted for disposition of certain repair 
conditions, this AD would require the repair of those conditions to be 
accomplished per a method approved by the FAA.

Explanation of Compliance Time for Work Package III

    The compliance time for Work Package III is 1,500 flight hours or 
750 flight cycles after doing the actions specified in Work Package II. 
(Work Package II has a compliance time of 90 days or 750 total flight 
cycles after

[[Page 13231]]

airplane delivery.) The inspections and corrective actions specified in 
Work Package III and Figure 2 of the service bulletin include only some 
of the actions specified in Work Package II and Figures 2 and 3 of the 
service bulletin. As a result, because the actions specified in Work 
Package III are less work-intensive than those actions in Work Package 
II, the FAA considers that the longer compliance time for Work Package 
III would provide an acceptable level of safety.

Interim Action

    This is interim action. The manufacturer has advised that it 
currently is developing a modification that will positively address the 
unsafe condition addressed by this AD. Once this modification is 
developed, approved, and available, the FAA may consider additional 
rulemaking.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Submit comments using the following format:
     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 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 rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-13-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2001-04-08  Boeing: Amendment 39-12127. Docket 2001-NM-13-AD.

    Applicability: Model 737-600, -700, -800, and -700C series 
airplanes, as listed in Boeing Alert Service Bulletin 737-55A1072, 
Revision 1, including Appendix A, dated January 11, 2001; 
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 (e) 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 reduced 
controllability of the airplane, do the following:

Initial and Repetitive Inspections, and Corrective Actions (Work 
Package I)

    (a) Within 30 days or 100 flight cycles after the effective date 
of this AD, whichever occurs later: Inspect the elevator tab, as 
specified in the Accomplishment Instructions for Work Package I of 
Boeing Alert Service Bulletin 737-55A1072, Revision 1, including 
Appendix A, dated January 11, 2001, to detect any damage or 
discrepancy per the service bulletin.
    (1) If no damage or discrepancy (including loose or missing 
parts, or excessive wear) is found, repeat the inspections required 
by paragraph (a) of this AD thereafter at intervals not to exceed 
250 flight cycles.
    (2) Except as provided by paragraph (d) of this AD, if any 
damage or discrepancy is found, before further flight, do the 
corrective actions (including follow-on inspections; replacing, 
reworking, repairing, and lubricating parts; applying inspection 
putty; cleaning; and aligning and torqueing components) specified in 
Figure 1 of the service bulletin, as applicable. Repeat the 
inspections required by paragraph (a) of this AD thereafter at 
intervals not to exceed 250 flight cycles.

One-Time Freeplay Inspections and Corrective Actions (Work Package II)

    (b) Within 90 days after the effective date of this AD, or 
before the accumulation of 750

[[Page 13232]]

total flight cycles after airplane delivery, whichever occurs later: 
Do the one-time free-play inspections of the elevator tab, as 
specified in the Accomplishment Instructions for Work Package II of 
Boeing Alert Service Bulletin 737-55A1072, Revision 1, including 
Appendix A, dated January 11, 2001, to detect any damage or 
discrepancy per the service bulletin.
    (1) If no damage or discrepancy is found, no further action is 
required by this paragraph.
    (2) If any damage or discrepancy is found, before further 
flight, do the corrective actions specified in Figures 2 and 3 of 
the service bulletin, as applicable.

Repetitive Inspections and Corrective Actions (Work Package III)

    (c) Within 1,500 flight hours or 750 flight cycles, whichever 
occurs earlier, after doing Work Package II: Inspect the elevator 
tab, as specified in the Accomplishment Instructions for Work 
Package III of Boeing Alert Service Bulletin 737-55A1072, Revision 
1, including Appendix A, dated January 11, 2001, to detect any 
damage or discrepancy per the service bulletin.
    (1) If no damage or discrepancy is found, repeat the inspections 
required by paragraph (c) of this AD thereafter at intervals not to 
exceed 1,500 flight hours or 750 flight cycles, whichever occurs 
earlier.
    (2) If any damage or discrepancy is found, before further 
flight, do the applicable corrective actions specified in Figure 2, 
as specified by the Accomplishment Instructions for Work Package 
III, of the service bulletin.

Repair

    (d) Repair any damage or discrepancy of the elevator tab 
assembly that is outside the limits specified by the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-55A1072, Revision 
1, including Appendix A, dated January 11, 2001, per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA, or per data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative (DER) who has been authorized by the Manager, Seattle 
ACO, to make such findings. For a repair method to be approved by 
the Manager, Seattle ACO, as required by this paragraph, the 
Manager's approval letter must specifically reference this AD.

Alternative Methods of Compliance

    (e) 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 ACO. 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.

Special Flight Permits

    (f) 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 done.

Incorporation by Reference

    (g) Except as provided by paragraph (d) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 737-
55A1072, Revision 1, including Appendix A, dated January 11, 2001. 
This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

    (h) This amendment becomes effective on March 20, 2001.

    Issued in Renton, Washington, on February 21, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-4761 Filed 3-2-01; 8:45 am]
BILLING CODE 4910-13-U