[Federal Register Volume 60, Number 80 (Wednesday, April 26, 1995)]
[Proposed Rules]
[Pages 20459-20461]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-10200]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-27-AD]
Airworthiness Directives; British Aerospace Model BAe 146-100A, -
200A, and -300A 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 British Aerospace Model
BAe 146-100A, -200A, and -300A airplanes. This proposal would require
modification of the elevator control system of the flight controls.
This proposal is prompted by reports of low frequency constant
amplitude oscillations of the elevator control system and non-centering
of the pitch control upon autopilot disconnect. The actions specified
by the proposed AD are intended to prevent uncommanded descent upon
autopilot disconnect and reduced controllability of the airplane
[[Page 20460]] due to low frequency constant amplitude oscillations.
DATES: Comments must be received by May 5, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-27-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 AVRO International Aerospace, Inc., 22111 Pacific Blvd.,
Sterling, Virginia 20166. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2148; fax (206) 227-1320.
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 95-NM-27-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-103, Attention: Rules
Docket No. 95-NM-27-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The Civil Aviation Authority (CAA), which is the airworthiness
authority for the United Kingdom, recently notified the FAA that an
unsafe condition may exist on certain British Aerospace Model BAe 146-
100A, -200A, and -300A airplanes. The CAA advises that it has received
several reports of the low frequency constant amplitude oscillations of
the elevator control system and non-centering of the pitch control upon
autopilot disconnect. Investigation revealed that one of the causes of
the oscillations may be attributed to ice accretion on the stabilizer
or elevator, which can reduce the aerodynamic damping of the elevator.
Investigation revealed that another cause of the oscillations may be
attributed to water or ice accumulation in the elevator, which can
adversely affect the elevator balance. Further investigation revealed
that the cause of the non-centering of the pitch control upon autopilot
disconnect may be attributed to lack of sufficient centering force to
overcome increased mechanical damping added to the elevator control
system by the `G' weight damper. These conditions, if not corrected,
could result in uncommanded descent and reduced controllability of the
airplane.
British Aerospace has issued Service Bulletin SB.27-77-00955A&C,
Revision 2, dated March 10, 1989, which describes procedures for
modifying the elevator control system of the flight controls by
installing two specific modifications:
1. Modification HCM00955A involves installation of a damper into
the elevator primary circuit at the `G' weight arm, and an electrical
heater mat and temperature switch to maintain the damper temperature
within a certain range. This modification will prevent a possible
control column oscillation at 2\1/2\ Hz.
2. Modification HCM00955C involves installation of a spring strut
between the column and fixed structure of the elevator control system.
This modification will increase column centering force in the aft
direction only.
The CAA classified the service bulletin as mandatory.
This airplane model is manufactured in the United Kingdom and is
type certificated for operation in the United States under the
provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR
21.29) and the applicable bilateral airworthiness agreement. Pursuant
to this bilateral airworthiness agreement, the CAA has kept the FAA
informed of the situation described above. The FAA has examined the
findings of the CAA, reviewed all available information, and determined
that AD action is necessary for products of this type design that are
certificated for operation in the United States.
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design registered
in the United States, the proposed AD would require modification of the
elevator control system of the flight controls. The actions would be
required to be accomplished in accordance with the service bulletin
described previously.
The FAA estimates that 38 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 4 work
hours per airplane to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Required parts would be
supplied by the manufacture at no cost to the operators. Based on these
figures, the total cost impact of the proposed AD on U.S. operators is
estimated to be $9,120, or $240 per airplane.
The total 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.
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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. [[Page 20461]] 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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
British Aerospace Regional Aircraft Limited, Avro International
Aerospace Division (Formerly British Aerospace, plc; British
Aerospace Commercial Aircraft Limited): Docket 95-NM-27-AD.
Applicability: Model BAe 146-00A, -200A, and -300A airplanes, as
listed in British Aerospace Service Bulletin SB.27-77-00955A&C,
Revision 2, dated March 10, 1989, 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 use the authority
provided in paragraph (b) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent uncommanded descend of the airplane and reduced
controllability of the airplane, accomplish the following:
(a) Within 60 days after the effective date of this AD, modify
the elevator control system of the flight controls in accordance
with British Aerospace Service Bulletin SB.27-77-00955A&C, Revision
2, dated March 10, 1989.
(b) 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, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate. Operators shall submit their
requests through an appropriate FAA Principal Maintenance Inspector,
who may add comments and then send it to the Manager,
Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(c) 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.
Issued in Renton, Washington, on April 20, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-10200 Filed 4-25-95; 8:45 am]
BILLING CODE 4910-13-U
