[Federal Register Volume 66, Number 124 (Wednesday, June 27, 2001)]
[Rules and Regulations]
[Pages 34098-34100]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-16051]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2001-NM-193-AD; Amendment 39-12294; AD 2001-12-51]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-800 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This document publishes in the Federal Register an amendment
adopting airworthiness directive (AD) 2001-12-51 that was sent
previously to all known U.S. owners and operators of all Boeing Model
737-800 series airplanes by individual notices. This AD requires
revising the Airplane Flight Manual (AFM) to prohibit operating the
airplane at speeds in excess of 300 knots indicated airspeed (KIAS)
with speedbrakes extended. This AD also provides for optional
terminating action for the AFM revision. This action is prompted by a
report indicating that severe vibration of the horizontal stabilizer
occurred on a Boeing Model 737-800 series airplane. The actions
specified by this AD are intended to prevent severe vibration of the
elevator and elevator tab assembly following deployment of the
speedbrakes, which, if not corrected, could result in severe damage to
the horizontal stabilizer, followed by loss of controllability of the
airplane.
DATES: Effective July 2, 2001, to all persons except those persons to
whom it was made immediately effective by emergency AD 2001-12-51,
issued June 13, 2001, which contained the requirements of this
amendment.
Comments for inclusion in the Rules Docket must be received on or
before August 27, 2001.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2001-NM-193-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-193-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.
Information pertaining to this amendment may be examined at the
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Nancy H. 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: On June 13, 2001, the FAA issued emergency
AD 2001-12-51, which is applicable to all Boeing Model 737-800 series
airplanes.
Background
The FAA has received a report indicating that severe vibration of
the horizontal stabilizer occurred on a Boeing Model 737-800 series
airplane. The airplane was operating at an altitude of 23,000 feet and
an airspeed of 320 knots indicated airspeed (KIAS). This high frequency
vibration was initiated by deployment of the speedbrakes during flight;
it continued unabated for approximately 40 seconds, even though the
speedbrakes were retracted.
Results of post-event analysis and investigation indicate that the
type of vibration of the elevator and elevator tab assembly following
deployment of the speedbrakes, if not corrected, could result in severe
damage to the horizontal stabilizer, followed by loss of
controllability of the airplane.
FAA's Conclusions
In light of this information, the FAA finds that certain new
limitations should be included in the FAA-approved Airplane Flight
Manual (AFM) for Model 737-800 series airplanes to prohibit operating
the airplane at speeds in excess of 300 KIAS with speedbrakes extended.
The FAA has determined that an airspeed of 300 KIAS provides an
acceptable safety margin compared to the 320-KIAS
[[Page 34099]]
airspeed at which the severe vibration occurred.
Other Similar Models
Operators should note that Model 737-600, -700, -700C, and -900
series airplanes are not included in the applicability of this AD.
Existing analysis and flight testing data have not shown that Model
737-600, -700, and -700C series airplanes are subject to this severe
vibration. Modified elevator tabs have already been installed on Model
737-900 series airplanes.
Explanation of Requirements of the Rule
Since the unsafe condition described is likely to exist or develop
on other airplanes of the same type design, the FAA issued emergency AD
2001-12-51 to prevent severe vibration of the elevator and elevator tab
assembly following deployment of the speedbrakes, which, if not
corrected, could result in severe damage to the horizontal stabilizer,
followed by loss of controllability of the airplane. The AD requires
revising the AFM to prohibit operating the airplane at speeds in excess
of 300 KIAS with speedbrakes extended. The AD also provides for
optional terminating action for the AFM revision.
Since the issuance of the emergency AD, an issue has been raised
about whether this limitation has the effect of prohibiting operation
at airspeeds above 300 KIAS in the event of an emergency descent (e.g.,
necessitated by rapid decompression of the fuselage). It was always the
FAA's intent that the pilot would be able to operate as necessary in
the event of an emergency as permitted in accordance with 14 CFR 91.3.
This AD does not change that authority.
Interim Action
This AD is considered to be interim action. The specific details of
the modification discussed previously are being developed, but are not
yet available for dissemination to affected operators. Once the
modification of the elevator tab assembly discussed previously is
developed, approved, and available, the FAA may consider further
rulemaking.
Since it was found that immediate corrective action was required,
notice and opportunity for prior public comment thereon were
impracticable and contrary to the public interest, and good cause
existed to make the AD effective immediately by individual notices
issued on June 13, 2001, to all known U.S. owners and operators of
Boeing Model 737-800 series airplanes. These conditions still exist,
and the AD is hereby published in the Federal Register as an amendment
to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to
make it effective to all persons.
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.
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-193-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, 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:
2001-12-51 Boeing: Amendment 39-12294. Docket 2001-NM-193-AD.
Applicability: All Model 737-800 series airplanes, 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 (c) 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 ensure that the flight crew is advised of the potential
hazard associated with extending the speedbrakes at speeds in excess
of 300 knots indicated airspeed (KIAS), accomplish the following:
Airplane Flight Manual (AFM) Revision
(a) Within 24 clock hours after the effective date of this AD,
revise the Limitations
[[Page 34100]]
Section of the FAA-approved AFM to include the following
information. This may be accomplished by inserting a copy of this AD
into the Limitations Section of the AFM.
``Do not operate the airplane at speeds in excess of 300 KIAS
with speedbrakes extended.
WARNING: Use of speedbrakes at speeds in excess of 320 KIAS
could result in a severe vibration, which, in turn, could cause
extreme damage to the horizontal stabilizer.''
Optional Terminating Action
(b) Modification or retrofit of the elevator tab assembly in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA, constitutes terminating action for
the AFM revision required by paragraph (a) of this AD. Following
such modification or retrofit, that AFM revision may be removed from
the AFM.
Alternative Methods of Compliance
(c) 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 Operations or
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.
Effective Date
(d) This amendment becomes effective on July 2, 2001, to all
persons except those persons to whom it was made immediately
effective by emergency AD 2001-12-51, issued on June 13, 2001, which
contained the requirements of this amendment.
Issued in Renton, Washington, on June 20, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 01-16051 Filed 6-26-01; 8:45 am]
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