[Federal Register Volume 68, Number 196 (Thursday, October 9, 2003)]
[Proposed Rules]
[Pages 58283-58285]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-25590]
========================================================================
Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
Federal Register / Vol. 68, No. 196 / Thursday, October 9, 2003 /
Proposed Rules
[[Page 58283]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2001-NM-266-AD]
RIN 2120-AA64
Airworthiness Directives; Bombardier Model DHC-8-102, -103, -106,
-201, -202, -301, -311, and -315 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to certain Bombardier DHC-8-
102, -103, -106, -201, -202, -301, -311, and -315 airplanes, that
currently requires inspections to detect breakage in the struts of the
rear mount strut assemblies on the left and right engine nacelles, and
replacement of any broken struts. The existing AD also requires
eventual replacement of all currently installed struts with new and/or
reworked struts, as terminating action for the inspections. This action
would require new repetitive inspections of the strut assemblies for
cracking of struts replaced per the existing AD, and replacement of any
cracked strut with a new, machined strut. This action also would change
the applicability of the existing AD by adding certain airplanes and
removing certain other airplanes, and would include an optional
terminating action for the repetitive inspections. The actions
specified by the proposed AD are intended to prevent failure of the
engine rear mount struts, 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. 2001-NM-266-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. 2001-NM-266-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: Jon Hjelm, Aerospace Engineer,
Airframe Branch, ANE-171, FAA, New York Aircraft Certification Office,
10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone
(516) 256-7523; 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 2001-NM-266-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. 2001-NM-266-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On February 14, 1994, the FAA issued AD 94-04-09, amendment 39-8829
(59 FR 8393, February 22, 1994), applicable to certain Bombardier Model
DHC-8-100 and DHC-8-300 airplanes, to require inspections to detect
breakage in the engine rear mount strut assemblies, and replacement of
broken struts. That AD also requires eventual replacement of all
currently installed struts with new and/or reworked struts, as
terminating action for the inspections. That action was prompted by
several reports of failure of the engine rear mount struts, due to
fracture at one of the rosette welds on the shank of the strut where
full weld depth was not achieved during manufacture. The requirements
of that AD are intended to prevent failure of the engine rear mount
struts, which could reduce the structural integrity of the nacelle and
engine support structure.
[[Page 58284]]
Actions Since Issuance of Previous Rule
Since the issuance of AD 94-04-09, we have been advised by
Transport Canada Civil Aviation (TCCA), which is the airworthiness
authority for Canada, of reports from the manufacturer and operators of
Model DHC-8-100 and DHC-8-300 airplanes indicating that replacement
struts installed per that AD have developed cracks. Therefore, the
engine rear mount strut has been redesigned and is pressed fit
assembled instead of welded which improves the endurance of the strut
to prevent failure due to cracking and/or fracture.
Explanation of Relevant Service Information
Bombardier has issued Service Bulletin 8-71-24, dated August 21,
2001, which describes procedures for replacing the existing rear mount
struts in a nacelle with new, improved struts. TCCA previously issued
Canadian airworthiness directive CF-2001-20, dated May 16, 2001, 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 supersede AD 94-04-09 to
require new repetitive inspections of the strut assemblies for cracking
of the struts replaced per the existing AD, and replacement of any
cracked strut with a new, machined strut. This proposed AD also would
change the applicability of the existing AD by adding certain airplanes
and removing certain other airplanes, and would include an optional
terminating action for the repetitive inspections.
Consistent with the findings of TCCA, this proposed AD would allow
repetitive inspections to continue in lieu of the terminating action.
In making this determination we considered that long-term continued
operational safety in this case will be adequately ensured by
repetitive inspections to find cracking before it represents a hazard
to the airplane.
Changes to the Applicability of the Existing AD
This proposed AD would expand the applicability in the existing AD
to include Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -
315 airplanes; serial numbers 003 through 509 inclusive. Model DHC-8-
102 and -103 series airplanes, serial numbers 003 through 310
inclusive; and Model DHC-8-301, -311, and -314 series airplanes, serial
numbers 100 through 311 inclusive, were identified in the existing AD.
Additionally, this proposed AD would remove Model DHC-8-314
airplanes, which were added to the applicability of the existing AD but
are not U.S. type-certificated.
Cost Impact
There are approximately 192 airplanes of U.S. registry that would
be affected by this proposed AD.
The actions that are currently required by AD 94-04-09 take
approximately 16 work hours per airplane to accomplish, at an average
labor rate of $65 per work hour. Required parts are provided by the
manufacturer at no cost to the operators. Based on these figures, the
cost impact of the currently required actions is estimated to be $1,040
per airplane.
The new detailed inspection that is proposed in this AD action
would take approximately 1 work hour per airplane to accomplish, at an
average labor rate of $65 per work hour. Based on these figures, the
cost impact of the proposed inspection on U.S. operators is estimated
to be $12,480, or $65 per airplane, per inspection cycle.
The cost impact figures discussed above are 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.
The optional terminating action, if done, would take approximately
16 work hours per strut to accomplish, at an average labor rate of $65
per work hour. Required parts would cost approximately $800 per strut.
Based on these figures, the cost impact of the optional terminating
action is estimated to be $1,840 per strut, per airplane.
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 removing amendment 39-8829 (59 FR
8393, February 22, 1994), and by adding a new airworthiness directive
(AD), to read as follows:
Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2001-NM-266-
AD. Supersedes AD 94-04-09, amendment 39-8829.
Applicability: Model DHC-8-102, -103, -106, -201, -202, -301, -
311, and -315
[[Page 58285]]
airplanes; serial numbers 003 through 509 inclusive; certificated in
any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the engine rear mount struts on the left
and right engine nacelles, which could result in reduced structural
integrity of the nacelle and engine support structure, accomplish
the following:
Repetitive Inspections
(a) Within 1,000 flight hours since installation of any new or
reworked rear mount strut per the replacement required by paragraph
(b) of AD 94-04-09, amendment 39-8829, or within 250 flight hours
after the effective date of this AD, whichever is later; do a
detailed inspection for cracking of each rear mount strut in the
left and right engine nacelles.
Note 1: Bombardier Service Bulletin 8-71-24, dated August 21,
2001, does not contain inspection procedures for the detailed
inspection required by paragraph (a) of this AD; however, the
definition of a detailed inspection is specified in Note 2 of this
AD.
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.''
(1) If no crack is found, repeat the inspection at intervals not
to exceed 250 flight hours, until accomplishment of paragraph (b) of
this AD.
(2) If any crack is found, before further flight, replace the
strut with a new, improved strut per Bombardier Service Bulletin 8-
71-24, dated August 21, 2001. Repeat the inspection thereafter at
intervals not to exceed 500 flight hours, for that nacelle only.
Optional Terminating Action
(b) Replacement of both rear mount struts in a nacelle with new,
improved struts, by doing all the actions specified in the Job Set-
up, Procedure, and Close-out sections of the Accomplishment
Instructions of Bombardier Service Bulletin 8-71-24, dated August
21, 2001, ends the repetitive inspections required by this AD for
that nacelle only. Replacement of both rear mount struts on both the
left and right engine nacelles ends the repetitive inspections
required by this AD.
Parts Installation
(c) As of the effective date of this AD, no person shall install
an engine rear mount strut, P/N 87110016-001, -003, -005, -007, -
009, or -011, on any airplane.
Alternative Methods of Compliance
(d) 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-2001-20, dated May 16, 2001.
Issued in Renton, Washington, on October 3, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-25590 Filed 10-8-03; 8:45 am]
BILLING CODE 4910-13-P