[Federal Register Volume 65, Number 181 (Monday, September 18, 2000)]
[Proposed Rules]
[Pages 56266-56268]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-23854]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-312-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 inspections 
of the fasteners in the elevator balance panel assemblies to detect 
various discrepancies; and corrective actions, if necessary. This 
proposal is prompted by a report that an elevator balance panel was 
found disconnected from the horizontal stabilizer due to the improper 
installation of fasteners during production. The actions specified by 
the proposed AD are intended to prevent jamming, restricting, or 
binding of the elevator control surfaces due to loose or missing 
fasteners, which could make the movement of the elevator difficult and 
decrease aerodynamic control of the airplane.

DATES: Comments must be received by October 18, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-312-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: Scott Fung, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1221; 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 statement is made: ``Comments 
to Docket Number. 99-NM-312-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-312-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that an elevator balance 
panel was found disconnected from the horizontal stabilizer on a Boeing 
Model 737-600 series airplane. Investigation revealed that the 
fasteners of the elevator balance panel were improperly installed 
during production. Investigation also revealed that the fasteners 
connecting the balance panel to the elevator did not have an adequate 
grip length. The installation of fasteners with inadequate grip lengths 
occurred during production. These conditions, if not corrected, could 
result in jamming, restricting, or binding of the elevator control 
surfaces, which could make the movement of the elevator difficult and 
decrease aerodynamic control of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-55A1064, dated October 15, 1998. Paragraph 3.A. of the 
Accomplishment Instructions of the service bulletin describes 
procedures for a detailed visual inspection of the fasteners in the 
elevator balance panel to detect inadequate grip length, gaps between 
the bolt head, washer, and structure, and missing fasteners; and 
follow-on actions. The follow-on actions include repetitive inspections 
(i.e., 250 flight hours) for certain conditions; repetitive daily 
inspections for certain other conditions and installation of new 
fasteners, if necessary, and accomplishment of the procedures specified 
in Paragraph 3.B. of the Accomplishment Instructions of the service 
bulletin (described below); as applicable.
    Paragraph 3.B. of the Accomplishment Instructions of the service 
bulletin describes procedures for a detailed visual inspection of the 
fasteners that attach the balance panels to the elevator and that 
attach the idler hinge to the stabilizer support beam for the correct 
length; inspection of related nut plates for correct locking torque; 
replacement of all fasteners and nut plates that are not satisfactory; 
and repair or replacement of any damaged

[[Page 56267]]

structures. Accomplishment of these actions would eliminate the need 
for the repetitive inspections described above.
    Accomplishment of the actions 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 accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below. 
The proposed AD also would require that operators report results of 
inspection findings to the FAA.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike the procedures described in 
Boeing Service Bulletin 737-55A1064, dated October 15, 1998, this 
proposed AD would not permit further flight if any of the following 
conditions are detected:
     Inadequate grip length or gaps between the bolt head, 
washer, and structure in the balance panel;
     Loose (i.e., minimum locking torque of nut plate not 
achieved) or missing fasteners;
     Any fastener with an inadequate grip length in the 
elevator balance panel assemblies.
    The FAA has determined that, because of the safety implications and 
consequences associated with such discrepant fasteners, any subject 
discrepant fastener that are found must be replaced with new fasteners, 
prior to further flight.
    Operators also should note that the service bulletin does not 
specify procedures for disposition of certain repair conditions. This 
proposed AD would require the repair of those conditions to be 
accomplished in accordance with a method approved by the FAA, or in 
accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the FAA to make such 
findings.
    The service bulletin recommends accomplishing the detailed visual 
inspection of the fasteners in the elevator balance panel within 250 
flight hours (after the release of the service bulletin). However, 
because of the low utilization rate of the affected airplanes and the 
degree of urgency associated with addressing the subject unsafe 
condition, the FAA has determined that accomplishing that inspection 
within 250 flight hours or 30 days after the effective date of this AD, 
whichever occurs first, represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.

Cost Impact

    There are approximately 123 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 52 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
11 work hours per airplane (including access and close up hours) to 
accomplish the proposed actions, and that the average labor rate is $60 
per work hour. Based on these figures, the cost impact of the proposed 
AD on U.S. operators is estimated to be $34,320, or $660 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 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 99-NM-312-AD.
    Applicability: Model 737-600, -700, and -800 series airplanes, 
as listed in Boeing Alert Service Bulletin 737-55A1064, dated 
October 15, 1998; 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 (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 jamming, restricting, or binding of the elevator 
control surfaces, which could make the movement of the elevator 
difficult and decrease aerodynamic control of the airplane, 
accomplish the following:

Inspections of Fasteners, and Corrective Action, If Necessary

    (a) Within 250 flight hours or 30 days after the effective date 
of this AD, whichever occurs first, perform a detailed visual 
inspection of the fasteners in the elevator balance panel to detect 
inadequate grip length, gaps between the bolt head, washer, and 
structure, and missing fasteners, in accordance with paragraph 3.A. 
of the Accomplishment Instructions of Boeing Service Bulletin 737-
55A1064, dated October 15, 1998.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect 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.''

    (1) If adequate grip length is detected, if no gap is detected, 
and if no fastener is missing, repeat the inspection thereafter at 
intervals

[[Page 56268]]

not to exceed 250 flight hours until the requirements of paragraph 
(b) of this AD have been accomplished; or prior to further flight, 
accomplish the actions specified in paragraph (b) of this AD.
    (2) If inadequate grip length is detected, if any gap is 
detected, or if any fastener is missing, prior to further flight, 
accomplish the actions specified in paragraph (b) of this AD.

Inspection and Corrective Actions, If Necessary

    (b) Within 3,000 flight cycles or 18 months after the effective 
date of this AD, whichever occurs later, perform a detailed visual 
inspection to detect missing fasteners at the locations specified in 
Figure 2 of Boeing Alert Service Bulletin 737-55A1064, dated October 
15, 1998, to detect inadequate grip length, and to determine the 
locking torque of the nut plates specified in Figure 2 of the 
service bulletin. These actions shall be done in accordance with 
paragraph 3.B. (``Fastener Inspection and Replacement'') of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
55A1064, dated October 15, 1998. Accomplishment of the inspection 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a)(1) of this AD.
    (1) If no loose (i.e., minimum locking torque of nut plate not 
achieved) fastener is detected, if no fastener is missing, and if 
adequate grip length is found, no further action is required by this 
paragraph.
    (2) If any fastener with an inadequate grip length is found, 
prior to further flight, replace the fastener with a new fastener in 
accordance with the service bulletin; and perform a detailed visual 
inspection of adjacent elevator and horizontal stabilizer structure 
to detect damage. If any damage is found on adjacent elevator or 
horizontal stabilizer structure, prior to further flight, repair or 
replace the damaged structure or component in accordance with the 
service bulletin.
    (3) If any nut plate is found to have inadequate locking torque, 
prior to further flight, install a new nut plate in accordance with 
a method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or in accordance with 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.
    (4) If any fastener is missing, prior to further flight, install 
a new fastener in accordance with the service bulletin; and perform 
a detailed visual inspection of adjacent elevator and horizontal 
stabilizer structure to detect damage. If any damage is found on 
adjacent elevator or horizontal stabilizer structure, prior to 
further flight, repair or replace the damaged structure or component 
in accordance with the service bulletin.

Reporting Requirement

    (c) Within 10 days after accomplishing any inspection required 
by paragraphs (a) and (b) [not including paragraph (b)(2)] of this 
AD, submit a report of the inspection results (positive findings 
only) to the Manager, Seattle Manufacturing Inspection District 
Office, ANM-108S, 2500 East Valley Road, Suite C-2, Renton, WA 
98055-4056; fax (425) 227-1159. Information collection requirements 
contained in this regulation have been approved by the Office of 
Management and Budget (OMB) under the provisions of the Paperwork 
Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been 
assigned OMB Control Number 2120-0056.

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 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 3: 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

    (e) 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 September 12, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-23854 Filed 9-15-00; 8:45 am]
BILLING CODE 4910-13-P