[Federal Register: October 9, 2003 (Volume 68, Number 196)]
[Proposed Rules]
[Page 58287-58289]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09oc03-19]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NM-78-AD]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-8-400, -401, and -
402 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 Bombardier Model DHC-8-
400, -401, and -402 airplanes. This proposal would require a one-time
inspection of the forward engine mount assemblies on the left and right
engine nacelles for installation of pre-production engine mount
assemblies, and follow-on corrective actions if necessary. This action
is necessary to prevent failure of the forward engine mount, which
could result in reduced structural integrity of the nacelle and engine
support structure. This action is intended to address the identified
unsafe condition.
DATES: Comments must be received by November 10, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2002-NM-78-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. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain ``Docket No. 2002-NM-78-AD'' in the subject line and need not
be submitted in triplicate. Comments sent via the Internet as attached
electronic files must be formatted in Microsoft Word 97 or 2000 or
ASCII text.
The service information referenced in the proposed rule may be
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division,
123 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, New York
Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley
Stream, New York.
FOR FURTHER INFORMATION CONTACT: Douglas G. Wagner, Aerospace Engineer,
Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft
Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New
York 11581; telephone (516) 256-7506; fax (516) 568-2716.
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 action may be changed in
light of the comments received.
Submit comments using the following format:
[sbull] Organize comments issue-by-issue. For example, discuss a
request to change the compliance time and a request to change the
service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed
AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each
request.
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 action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2002-NM-78-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-114, Attention: Rules
Docket No. 2002-NM-78-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
Transport Canada Civil Aviation (TCCA), which is the airworthiness
authority for Canada, notified the FAA that an unsafe condition may
exist on certain Bombardier Model DHC-8-400, -401, and -402 airplanes.
TCCA advises that the manufacturer of the forward engine mount assembly
has indicated that an unapproved pre-production engine mount assembly
was found installed in place of a production engine mount assembly.
Pre-production engine mount assemblies are more susceptible to fatigue
cracking than production engine mount assemblies. In addition, there is
a possibility that pre-production assemblies having part number (P/N)
96042-07 are incorrectly marked with P/N 96042-09, which is the P/N on
the production assemblies. Operation with pre-production engine mount
assemblies could result in failure of the forward engine mount, and
consequent reduced structural integrity of the nacelle and engine
support structure.
Explanation of Relevant Service Information
Bombardier has issued Alert Service Bulletin A84-71-06, Revision
``A,'' dated December 5, 2001, which describes procedures for a visual
inspection to determine the P/N and configuration of the forward engine
mount assemblies on the left and right engine nacelles. If the
inspection shows that any pre-production engine mount assembly is
installed, the service bulletin describes procedures for follow-on
corrective actions for that assembly.
[[Page 58288]]
Those actions include repetitive detailed visual inspections of each
assembly for cracking at intervals of 250 flight cycles, and
replacement of the pre-production engine mount assembly with a
production engine mount assembly before further flight if cracking is
found. If no cracking is found, the service bulletin specifies that the
pre-production engine mount assembly may remain in service for up to
1,000 flight cycles after the initial inspection, and then reworked or
replaced with a production engine mount assembly. If both engine mounts
on the same nacelle have the pre-production configuration, the service
bulletin specifies that one pre-production engine mount assembly must
be replaced with a production engine mount assembly before further
flight. The service bulletin also includes a repair letter issued by
the engine manufacturer which contains rework procedures for the pre-
production engine mount assembly. Accomplishment of the actions
specified in the service bulletin is intended to adequately address the
identified unsafe condition.
TCCA classified this service bulletin as mandatory and issued
Canadian airworthiness directive CF-2002-07, dated January 21, 2002, to
ensure the continued airworthiness of these airplanes in Canada.
FAA's Conclusions
These airplane models are manufactured in Canada and are 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, TCCA has kept us informed of the
situation described above. We have examined the findings of TCCA,
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 accomplishment of
the actions specified in the service bulletin described previously,
except as discussed below.
Differences Between Canadian Airworthiness Directive, Service Bulletin,
and Proposed Rule
The service bulletin and Canadian airworthiness directive specify a
visual inspection to determine the P/N and configuration of the forward
engine mount assemblies, but this proposed rule would require a general
visual inspection. A note has been added to the proposed rule to define
that inspection.
The service bulletin and Canadian airworthiness directive also
specify a detailed visual inspection for cracking if a pre-production
engine mount is installed, but this proposed rule would require a
detailed inspection. A note has been added to the proposed rule to
define that inspection.
Cost Impact
We estimate that 11 airplanes of U.S. registry would be affected by
this proposed AD, that it would take approximately 2 work hours per
airplane to accomplish the proposed inspection, and that the average
labor rate is $65 per work hour. Based on these figures, the cost
impact of the proposed AD on U.S. operators is estimated to be $1,430,
or $130 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. The cost impact figures
discussed in AD rulemaking actions represent only the time necessary to
perform the specific actions actually required by the AD. These figures
typically do not include incidental costs, such as the time required to
gain access and close up, planning time, or time necessitated by other
administrative actions.
Regulatory Impact
The regulations proposed herein would not have a substantial direct
effect 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, it
is determined that this proposal would not have federalism implications
under Executive Order 13132.
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:
Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2002-NM-78-
AD.
Applicability: Model DHC-8-400, -401, and -402 airplanes; serial
numbers 4005, 4006, 4008 through 4016 inclusive, 4018 through 4051
inclusive, and 4053; certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the forward engine mount, which could
result in reduced structural integrity of the nacelle and engine
support structure, accomplish the following:
Inspection
(a) Within 100 flight cycles after the effective date of this
AD: Do a general visual inspection of the forward engine mount
assemblies on the left and right engine nacelles for installation of
pre-production assemblies (determine the part number and
configuration for each assembly), per the Accomplishment
Instructions of Bombardier Alert Service Bulletin A84-71-06,
Revision ``A,'' dated December 5, 2001. If no pre-production engine
mount assembly is installed, no further action is required by this
AD.
Note 1: For the purposes of this AD, a general visual inspection
is defined as: ``A visual examination of an interior or exterior
area, installation, or assembly to detect obvious damage, failure,
or irregularity. This level of inspection is made from within
touching distance unless otherwise specified. A mirror may be
necessary to enhance visual access to all exposed surfaces in the
[[Page 58289]]
inspection area. This level of inspection is made under normally
available lighting conditions such as daylight, hangar lighting,
flashlight, or droplight and may require removal or opening of
access panels or doors. Stands, ladders, or platforms may be
required to gain proximity to the area being checked.''
Follow-On Corrective Actions
(b) If any pre-production engine mount assembly is installed, do
all the applicable follow-on corrective actions (including
repetitive detailed inspections for cracking, and rework or
replacement of the pre-production engine mount assembly, if
necessary) per all the actions specified in the Accomplishment
Instructions of the service bulletin, at the applicable times
specified in Paragraph I., Part D., ``Compliance,'' of the service
bulletin. Any replacement due to cracking must be done before
further flight.
Note 2: For the purposes of this AD, a detailed inspection is
defined as: ``An intensive visual examination of a specific
structural area, system, installation, or assembly to detect damage,
failure, or irregularity. Available lighting is normally
supplemented with a direct source of good lighting at intensity
deemed appropriate by the inspector. Inspection aids such as mirror,
magnifying lenses, etc., may be used. Surface cleaning and elaborate
access procedures may be required.''
Optional Terminating Action for Follow-On Repetitive Inspections
(c) Installation of production engine mount assemblies on all
four forward engine mounts ends the repetitive inspection
requirements of paragraph (b) of this AD.
Part Installation
(d) As of the effective date of this AD, no person may install
an engine mount assembly having a pre-production configuration and/
or part number 96042-07 on any airplane, unless the assembly has
been reworked per Part B of the Accomplishment Instructions of
Bombardier Alert Service Bulletin A84-71-06, Revision ``A,'' dated
December 5, 2001.
Alternative Methods of Compliance
(e) In accordance with 14 CFR 39.19, the Manager, New York
Aircraft Certification Office, FAA, is authorized to approve
alternative methods of compliance for this AD.
Note 3: The subject of this AD is addressed in Canadian
airworthiness directive CF-2002-07, dated January 21, 2002.
Issued in Renton, Washington, on October 3, 2003.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-25588 Filed 10-8-03; 8:45 am]
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