[Federal Register Volume 68, Number 196 (Thursday, October 9, 2003)]
[Proposed Rules]
[Pages 58287-58289]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-25588]


-----------------------------------------------------------------------

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).

-----------------------------------------------------------------------

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: 
[email protected]. 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]
BILLING CODE 4910-13-P