[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