[Federal Register Volume 59, Number 78 (Friday, April 22, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-9728]
[[Page Unknown]]
[Federal Register: April 22, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-20-AD]
Airworthiness Directives; De Havilland Model DHC-8 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 de Havilland Model DHC-8
series airplanes. This proposal would require removal of the aluminum
or brass hardware in the firewall terminal block and battery shunt
cable assemblies and replacement with steel hardware. This proposal is
prompted by the results of an investigation, which revealed that
corroded aluminum washers in the DC firewall terminal block and battery
shunt cable assemblies may loosen the electrical connections. The
actions specified by the proposed AD are intended to prevent
interruption of DC electrical power due to connections that may have
loosened from corrosion.
DATES: Comments must be received by June 3, 1994.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-20-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.
The service information referenced in the proposed rule may be
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division,
Garratt Boulevard, Downsview, Ontario, M3K 1Y5, Canada. This
information may be examined at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the FAA Engine and
Propeller Directorate, New York Aircraft Certification Office, 181
South Franklin Avenue, room 202, Valley Stream, New York.
FOR FURTHER INFORMATION CONTACT: Peter Cuneo, Electrical Engineer,
Systems and Equipment Branch, ANE-173, FAA, Engine and Propeller
Directorate, New York Aircraft Certification Office, 181 South Franklin
Avenue, room 202, Valley Stream, New York 11581; telephone (516) 791-
6427; fax (516) 791-9024.
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-20-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-20-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
Transport Canada Aviation, which is the airworthiness authority for
Canada, recently notified the FAA that an unsafe condition may exist on
all de Havilland Model DHC-8 series airplanes. Transport Canada
Aviation advises that the results of an investigation revealed that
aluminum washers used in the DC firewall terminal block and battery
shunt cable assemblies of all Model DHC-8 series airplanes could cause
corrosion at the electrical connections. Such corrosion could either
loosen a connection and/or generate a high electrical resistance at the
connection points. This condition, if not corrected, could result in
interruption of DC electrical power due to connections that may have
loosened from corrosion.
Bombardier, Inc., has issued de Havilland Service Bulletin S.B. 8-
24-47, Revision `A', dated November 29, 1993, that describes procedures
for removal of the aluminum or brass hardware in the firewall terminal
block and battery shunt cable assemblies and replacement with steel
hardware (Modification 8/1984). Transport Canada Aviation classified
this service bulletin as mandatory and issued Canadian Airworthiness
Directive CF-93-31, dated December 17, 1993, in order to assure the
continued airworthiness of these airplanes in Canada.
This airplane model is manufactured in Canada and is type
certificated for operation in the United States under the provisions of
Sec. 21.29 of the Federal Aviation Regulations and the applicable
bilateral airworthiness agreement. Pursuant to this bilateral
airworthiness agreement, Transport Canada Aviation has kept the FAA
informed of the situation described above. The FAA has examined the
findings of Transport Canada Aviation, 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 removal of the
aluminum or brass hardware in the firewall terminal block and battery
shunt cable assemblies and replacement with steel hardware
(Modification 8/1984). The actions would be required to be accomplished
in accordance with the service bulletin described previously.
The FAA estimates that 130 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 3 work
hours per airplane to accomplish the proposed actions, and that the
average labor rate is $55 per work hour. Required parts would be
nominal in cost. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $21,450, or $165 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 14
CFR part 39 of the Federal Aviation Regulations 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:
De Havilland, Inc.: Docket 94-NM-20-AD.
Applicability: All Model DHC-8 series airplanes, certificated in
any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent interruption of DC electrical power due to
connections that may have loosened from corrosion, accomplish the
following:
(a) Within 60 days after the effective date of this AD, remove
the aluminum or brass hardware in the firewall terminal block and
battery shunt cable assemblies and replace with steel hardware
(Modification 8/1984), in accordance with de Havilland Service
Bulletin S.B. 8-24-47, Revision `A,' dated November 29, 1993.
(b) As of the effective date of this AD, no person shall install
on any airplane a terminal block, part number 72470052-101 or
82450068-001, unless it has been previously reworked and bears the
identification 8/1984.
(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, New York Aircraft Certification
Office (ACO), FAA, Engine and Propeller Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, New York ACO.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York ACO.
(d) Special flight permits may be issued in accordance with
Federal Aviation Regulations (FAR) 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 18, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-9728 Filed 4-21-94; 8:45 am]
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