[Federal Register Volume 62, Number 40 (Friday, February 28, 1997)]
[Proposed Rules]
[Pages 9111-9113]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4948]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-05-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Model Avro 146-RJ 
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 all British Aerospace Model Avro 
146-RJ series airplanes. This proposal would require modifying the 
electrical system in the equipment bay area by replacing certain 
cables, clamps, and fairleads. This proposal is prompted by a report 
indicating that the incorrect size of electrical cables were used in 
the generator feeder circuit between certain busbars and existing 
generator feeder cables. As a result, generator contactors are not 
compatible with generator rating requirements and can overheat. The 
actions specified by the proposed AD are intended to prevent possible 
overheating and damage to the electrical generator feeder cables, which 
could cause a fire or the loss of essential electrical systems.

DATES: Comments must be received by April 9, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-05-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 British Aerospace Regional Aircraft Limited, Avro 
International Aerospace Division, Customer Support, Woodford Aerodrome, 
Woodford, Cheshire SK7 1QR, England. This information may be examined 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Tim Backman, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2797; fax (206) 227-1149.

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 97-NM-05-AD.'' The

[[Page 9112]]

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. 97-NM-05-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 all British Aerospace Model Avro 146-RJ 
series airplanes. The CAA advises that, in the electrical equipment 
bay, a design drawing error allowed the incorrect size of electrical 
cables to be used in the aircraft generator feeder circuit between 
busbars AC1 and AC2. For this reason, existing 6ANC generator feeder 
cables between AC1 and AC2 busbars and generator contactors are not 
compatible with generator rating requirements. When only one 
alternating current (AC) generator is on-line and the AC hydraulic pump 
is operating, the feeder cable could overheat and cause damage. This 
condition, if not corrected, could result in a possible fire or loss of 
essential electrical systems.

Explanation of Relevant Service Information

    British Aerospace has issued Service Bulletin SB.24-113-01532A, 
dated March 12, 1996, and Revision 1, dated June 18, 1996, which 
describe procedures for replacing the existing 6ANC generator feeder 
cables installed between the AC1 and AC2 busbars; replacing the 
generator contactors with larger 4ANC size cables; and modifying 
existing clamps and fairleads to accommodate the larger diameter 
cables. This modification is identified as HCM01532A in the service 
bulletin.
    Replacing the electrical cables and modifying the various 
components in the electrical equipment bay in accordance with the 
service bulletin will preclude possible feeder cable overheat and 
subsequent damage that could lead to a fire or loss of essential 
systems.
    The CAA classified this service bulletin as mandatory and issued 
British airworthiness directive 006-03-96, dated March 12, 1996, in 
order to assure the continued airworthiness of these airplanes in the 
United Kingdom.

FAA's Conclusions

    This airplane model is manufactured in the United Kingdom and is 
type certificated for operation in the United States under the 
provisions of section 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.

Explanation of Requirements of Proposed Rule

    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 modifying the 
electrical system in the electrical equipment bay. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.

Cost Impact

    The FAA estimates that 10 British Aerospace Model Avro 146-RJ 
series 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 cost approximately $300 per 
airplane. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $5,400, or $540 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 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. 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:

British Aerospace Regional Aircraft Limited, Avro International 
Aerospace Division (Formerly British Aerospace, plc; British 
Aerospace Commercial Aircraft Limited): Docket 97-NM-05-AD.

    Applicability: All Model Avro 146-RJ 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 
otherwise 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 (b) 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 the possible overheating of the feeder cable and 
subsequent damage, which could lead to a possible fire or loss of 
essential electrical systems, accomplish the following:
    (a) Prior to the accumulation of 500 flight cycles after the 
effective date of this

[[Page 9113]]

    AD, modify the electrical system in the electrical equipment bay 
in accordance with British Aerospace Service Bulletin SB.24-113-
01532A, dated March 12, 1996, or Revision 1, dated June 18, 1996.
    (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 
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 February 21, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-4948 Filed 2-27-97; 8:45 am]
BILLING CODE 4910-13-U