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

[Federal Register Volume 66, Number 57 (Friday, March 23, 2001)]
[Rules and Regulations]
[Pages 16116-16118]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-7173]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-19-AD; Amendment 39-12155; AD 2001-06-08]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, and -800 
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, and -800 series 
airplanes. This action requires repetitive inspections of certain 
elevator hinge plates, and corrective action, if necessary. This action 
also provides for an optional replacement of the elevator hinge plates 
with new, improved hinge plates, which would end the repetitive 
inspections. This action is necessary to detect and correct fatigue 
cracking of the elevator hinge plates, which could lead to the loss of 
the attachment of the elevator to the horizontal stabilizer, and 
consequent reduced controllability of the airplane. This action is 
intended to address the identified unsafe condition.

DATES: Effective April 9, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 9, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before May 22, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-19-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-19-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 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 a report that, during 
flight testing of Boeing Model 737-600, -700,

[[Page 16117]]

and -800 series airplanes, the elevator hinge plates at elevator hinges 
3, 4, 5, 6, 7, and 8 experienced higher-than-expected loads due to 
buffeting by the spoiler. The higher loads reduce the service life of 
the elevator hinge plates. Reduced service life of the elevator hinge 
plates could lead to fatigue cracking of the elevator hinge plates in 
service. Such cracking could lead to the loss of the attachment of the 
elevator to the horizontal stabilizer, and consequent reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 737-55-
1067, dated October 19, 2000, which describes instructions for the 
following:
    <bullet> Repetitive detailed visual inspections of the elevator 
hinge plate lugs (three locations) at elevator hinges 3, 5, 6, 7, and 
8.
    <bullet> Repetitive high frequency eddy current (HFEC) and detailed 
visual inspections of the hinge plate at elevator hinge 4. (Analysis 
has shown that the hinge plate at elevator hinge 4 is most critical; 
therefore, in addition to the detailed visual inspection, an HFEC 
inspection is necessary for elevator hinge 4.)
    <bullet> Corrective actions, which entail replacement of the hinge 
plate with a new part, if any crack or unusual wear is found on a hinge 
plate. (For the purposes of this AD, unusual wear is defined as 
elongated holes, loose or missing nuts or bolts, or missing primer or 
finish.)
    <bullet> Replacement of the elevator hinge plates at hinges 3, 4, 
5, 6, 7, and 8, with new, improved hinge plates, and modification of 
the elevator upper skin, the upper and lower hinge covers, and the 
upper and lower closure panels, as applicable. Doing these actions 
eliminates the need to do the repetitive inspections.

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 detect and correct fatigue cracking of the elevator 
hinge plates, which could lead to the loss of the attachment of the 
elevator to the horizontal stabilizer, and consequent reduced 
controllability of the airplane. This AD requires accomplishment of the 
actions specified in the service bulletin described previously, except 
as discussed below.

Difference Between This AD and the Service Bulletin

    Operators should note that the service bulletin recommends doing 
the inspections prior to the accumulation of 7,000 total flight cycles 
on the airplane. The FAA finds that such a compliance time could put 
some airplanes out of compliance as of the effective date of this AD if 
the airplane already has accumulated more than 7,000 total flight 
cycles before the effective date of the AD. Therefore, this AD provides 
a grace period of 90 days after the effective date of this AD for the 
inspection for airplanes that are close to or over the threshold of 
7,000 total flight cycles.
    Operators also should note that, although the service bulletin 
specifies to contact Boeing for wear limits during replacement of 
elevator hinge plates, this AD requires that such wear limits be 
obtained from the Manager, Seattle Aircraft Certification Office (ACO), 
FAA, or a Boeing Company Designated Engineering Representative who has 
been authorized by the Manager, Seattle ACO, to make such findings.

Interim Action

    This is considered to be interim action. The service bulletin 
recommends the replacement of elevator hinge plates prior to the 
accumulation of 15,000 total flight cycles, or within 5 years since 
date of delivery of the airplane, whichever occurs first. This AD 
provides for the replacement as optional. The FAA is currently 
considering requiring the replacement of the elevator hinge plates with 
new parts, which is described in the service bulletin and which would 
constitute terminating action for the repetitive inspections required 
by this AD action. However, the planned compliance time for the 
replacement is sufficiently long so that notice and opportunity for 
prior public comment will be practicable.

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:
    <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 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 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-19-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

[[Page 16118]]

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:

2001-06-08  Boeing: Amendment 39-12155. Docket 2001-NM-19-AD.

    Applicability: Model 737-600, -700, and -800 series airplanes; 
line numbers 1 through 84 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 (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 detect and correct cracking of the elevator hinge plates, 
which could lead to the loss of the attachment of the elevator to 
the horizontal stabilizer, and consequent reduced controllability of 
the airplane, accomplish the following:

Inspections and Corrective Actions

    (a) Prior to the accumulation of 7,000 total flight cycles or 
within 90 days after the effective date of this AD, whichever occurs 
later, perform high frequency eddy current and detailed visual 
inspections of the hinge plate at elevator hinge 4, and a detailed 
visual inspection of the elevator hinge plate lugs (three locations) 
at elevator hinges 3, 5, 6, 7, and 8. Do these inspections per Part 
I of the Accomplishment Instructions of Boeing Service Bulletin 737-
55-1067, dated October 19, 2000. Repeat the inspections thereafter 
no later than every 4,000 flight cycles, per the service bulletin, 
until paragraph (b) of this AD has been accomplished. If any 
cracking or unusual wear (i.e., elongated holes, loose or missing 
nuts or bolts, or missing primer or finish) is found during any 
inspection per this paragraph, before further flight, replace the 
affected hinge plate with a new, improved hinge plate, and modify 
the elevator upper skin, the upper and lower hinge covers, and the 
upper and lower closure panels, as applicable, per the service 
bulletin, except as provided by paragraph (c) of this AD. Such 
replacement and modification ends the repetitive inspections for the 
replaced hinge plate.

    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.''

Optional Replacement of Hinge Plates

    (b) Replacement of the elevator hinge plates at hinges 3, 4, 5, 
6, 7, and 8, with new, improved hinge plates; including modification 
of the elevator upper skin, the upper and lower hinge covers, and 
the upper and lower closure panels, as applicable; per Part II of 
the Accomplishment Instructions of Boeing Service Bulletin 737-55-
1067, dated October 19, 2000, except as provided by paragraph (c) of 
this AD; ends the repetitive inspections required by this AD.

Exception to Service Bulletin Instructions: Wear Limits

    (c) During the replacement of elevator hinge plates per 
paragraph (a) or (b) of this AD, where Boeing Service Bulletin 737-
55-1067, dated October 19, 2000, specifies to contact Boeing for 
wear limits, before further flight, contact the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, or a Boeing Company 
Designated Engineering Representative who has been authorized by the 
Manager, Seattle ACO, to make such findings. For wear limits 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

    (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 
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.

Incorporation by Reference

    (f) Except as provided by paragraph (c) of this AD, the actions 
shall be done in accordance with Boeing Service Bulletin 737-55-
1067, dated October 19, 2000. 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

    (g) This amendment becomes effective on April 9, 2001.

    Issued in Renton, Washington, on March 15, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-7173 Filed 3-22-01; 8:45 am]
BILLING CODE 4910-13-U

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