[Federal Register Volume 59, Number 220 (Wednesday, November 16, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-28245]
[[Page Unknown]]
[Federal Register: November 16, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-126-AD]
Airworthiness Directives; British Aerospace Model BAe 146-100A, -
200A, and -300A 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 BAe
146-100A, -200A, and -300A series airplanes. This proposal would
require conducting closed loop tests to determine the setting of the
underfrequency trip level on suspect generator control units (GCU), and
either the correction of discrepancies or replacement of the GCU. This
proposal is prompted by several malfunctions of in-service GCU's due to
the effects of setting the underfrequency trip level too high. The
actions specified by the proposed AD are intended to correct GCU's that
may have the underfrequency level set too high, which could result in
the unwanted shut down of an electrical generator; this condition may
lead to loss of all generated electrical power on the airplane when
other generator faults or failures occur.
DATES: Comments must be received by January 13, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-126-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 Holdings, Inc., Avro International
Aerospace Division, P.O. Box 16039, Dulles International Airport,
Washington DC 20041-6039; and GEC-Marconi Aerospace Ltd, Titchfield,
Fareham, Hampshire P014 4QA, England. 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,
ANM-113, 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 94-NM-126-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. 94-NM-126-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 BAe 146-100A,
-200A, and -300A series airplanes. The CAA advises that reports have
been received of several malfunctions of in-service generator control
units (GCU). Investigation revealed that GCU's repaired or adjusted by
workshops other than GEC-Marconi may have the underfrequency trip level
set too high. The cause has been attributed to the fact that the GEC-
Marconi Component Maintenance Manual does not recommend that the
underfrequency trip level be checked during the closed loop test. (GEC-
Marconi is the manufacturer of the subject GCU's.) Setting the
underfrequency level too high could lead to the shut down of an
electrical generator. If an electrical generator shuts down when other
generator faults or failures occur, all generated electrical power on
the airplane may be lost.
Avro International Aerospace (a division of British Aerospace) has
issued Service Bulletin S.B. 24-103, dated March 24, 1994, which
describes procedures for checking the part and serial number on the
data plate of each GCU to identify discrepant units, replacing the
discrepant GCU with a serviceable unit, and conducting post assembly
testing. The CAA classified this service bulletin as mandatory.
GEC-Marconi has issued Service Bulletin HGE 24-23, dated March 11,
1994, which describes procedures for conducting closed loop tests to
determine the setting of the underfrequency trip level, adjusting the
underfrequency trip level, and conducting post assembly testing. This
service bulletin also describes the part and serial number of affected
GCU's.
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 checking the part
and serial number on the data plate of each GCU to identify discrepant
units, and conducting closed loop tests on affected GCU's to determine
the setting of the underfrequency trip level. The proposed AD would
also require either adjusting the underfrequency trip level or
replacing the discrepant GCU with a serviceable unit, and conducting
post assembly testing. The actions would be required to be accomplished
in accordance with the service bulletins described previously.
The FAA estimates that 43 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 1 work
hour per airplane to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the proposed AD on U.S. operators is estimated to
be $2,580, or $60 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. 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 94-NM-126-AD.
Applicability: All Model British Aerospace Model BAe 146-100A, -
200A, and -300A series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously. -To correct generator control units (GCU) that may have
the under-frequency trip level set too high, which could lead to the
unwanted shut down of an electrical generator, accomplish the
following:
(a) Within 6 months after the effective date of this AD, check
the part and serial number on the data plate of each generator
control unit (GCU). If the part number is one of those affected and
the serial number is listed in Addendum 1 of GEC-Marconi Service
Bulletin HGE 24-23, dated March 11, 1994, prior to further flight,
conduct a closed loop test to determine the setting of the
underfrequency trip level, in accordance with that service bulletin.
(1) If the level exceeds that specified in GEC-Marconi Service
Bulletin HGE 24-23, dated March 11, 1994, prior to further flight,
adjust the level in accordance with that service bulletin; or
replace the GCU with a serviceable unit, in accordance with Avro
Service Bulletin S.B. 24-103, dated March 24, 1994.
(2) Prior to further flight, after adjustment or replacement of
the GCU as required by paragraph (a)(1) of this AD, conduct the post
assembly testing in accordance with Avro Service Bulletin S.B. 24-
103, dated March 24, 1994.
(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: 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 November 9, 1994.
S.R. Miller, Acting Manager,
Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-28245 Filed 11-15-94; 8:45 am]
BILLING CODE 4910-13-U
