Airworthiness Directives; Bombardier Model DHC-8-400 Series Airplanes

[Federal Register Volume 70, Number 114 (Wednesday, June 15, 2005)]
[Rules and Regulations]
[Pages 34641-34642]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-11695]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20860; Directorate Identifier 2005-NM-043-AD; 
Amendment 39-14131; AD 2005-12-15]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model DHC-8-400 Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Bombardier Model DHC-8-400 series airplanes. This AD requires 
revising the Airworthiness Limitation section of the Instructions for 
Continued Airworthiness of the Dash 8 400 Series (Bombardier) 
Maintenance Requirements Manual to reduce the life limits of the main 
landing gear (MLG) orifice support tube, upper bearing, and piston 
plug; and to reduce the threshold for initiating repetitive detailed 
inspections for cracking of the engine isolator brackets. This AD is 
prompted by the discovery of fatigue failures, during type 
certification fatigue testing, at the engine isolator bracket and at 
the orifice support tube, upper bearing, and piston plug in the shock 
strut assembly of the MLG, which are principal structural elements. We 
are issuing this AD to prevent the development of cracks in these 
principal structural elements, which could reduce the structural 
integrity of the engine installation and the MLG. Reduced structural 
integrity of the engine installation could result in separation of the 
engine from the airplane, and reduced structural integrity of the MLG 
could result in collapse of the MLG.

DATES: This AD becomes effective July 20, 2005.
    The incorporation by reference of certain publications listed in 
the AD is approved by the Director of the Federal Register as of July 
20, 2005.

ADDRESSES: For service information identified in this AD, contact 
Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt 
Boulevard, Downsview, Ontario M3K 1Y5, Canada.
    Docket: The AD docket contains the proposed AD, comments, and any 
final disposition. You can examine the AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility 
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, 
Washington, DC. This docket number is FAA-2005-20860; the directorate 
identifier for this docket is 2005-NM-043-AD.

FOR FURTHER INFORMATION CONTACT: George Duckett, Aerospace Engineer, 
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft 
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New 
York 11590; telephone (516) 228-7325; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with an AD for certain Bombardier Model DHC-8-400 series airplanes. 
That action, published in the Federal Register on April 6, 2005 (70 FR 
17354), proposed to require revising the Airworthiness Limitation 
section of the Instructions for Continued Airworthiness of the Dash 8 
400 Series (Bombardier) Maintenance Requirements Manual to reduce the 
life limits of the main landing gear (MLG) orifice support tube, upper 
bearing, and piston plug; and to reduce the threshold for initiating 
repetitive detailed inspections for cracking of the engine isolator 
brackets.

Explanation of Change to Applicability

    We have revised the applicability of the proposed AD to identify 
model designations as published in the most recent type certificate 
data sheet for the affected models.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. No comments have been submitted on the proposed 
AD or on the determination of the cost to the public.

Conclusion

    We have carefully reviewed the available data and determined that 
air safety and the public interest require adopting the AD with the 
change described previously. We have determined that this change will 
neither increase the economic burden on any operator nor increase the 
scope of the AD.

Costs of Compliance

    There are about 93 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 21 airplanes of U.S. 
registry. The actions will take about 1 work hour per airplane, at an 
average labor rate of $65 per work hour. Based on these figures, the 
estimated cost of the AD for U.S. operators is $1,365, or $65 per 
airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;

[[Page 34642]]

    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD. See the ADDRESSES section for a location to 
examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2005-12-15 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 
39-14131. Docket No. FAA-2005-20860; Directorate Identifier 2005-NM-
043-AD.

Effective Date

    (a) This AD becomes effective July 20, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Bombardier Model DHC-8-400 series 
airplanes, certificated in any category; serial numbers 4001, and 
4003 through 4094 inclusive.

    Note 1: This AD requires revision to a certain operator 
maintenance document to include a new replacement time. Compliance 
with this replacement time is required by 14 CFR 91.403(c). For 
airplanes that have been previously modified, altered, or repaired 
in the areas addressed by this replacement time, the operator may 
not be able to accomplish the replacement described in the revision. 
In this situation, to comply with 14 CFR 91.403(c), the operator 
must request approval for an alternative method of compliance 
according to paragraph (g) of this AD. The request should include a 
description of changes to the required replacement time that will 
ensure the continued damage tolerance of the affected structure. The 
FAA has provided guidance for this determination in Advisory 
Circular (AC) 25-1529.

Unsafe Condition

    (d) This AD was prompted by the discovery of fatigue failures, 
during type certification fatigue testing, at the engine isolator 
bracket and at the orifice support tube, upper bearing, and piston 
plug in the shock strut assembly of the main landing gear (MLG), 
which are principal structural elements. We are issuing this AD to 
prevent the development of cracks in these principal structural 
elements, which could reduce the structural integrity of the engine 
installation and MLG. Reduced structural integrity of the engine 
installation could result in separation of the engine from the 
airplane, and reduced structural integrity of the MLG could result 
in collapse of the MLG.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Revisions to Airworthiness Limitation (AWL) Section

    (f) Within 30 days after the effective date of this AD, revise 
the AWL section of the Instructions for Continued Airworthiness of 
the Dash 8 400 Series (Bombardier) Maintenance Requirements Manual, 
PSM 1-84-7, by doing the actions specified in paragraphs (f)(1) and 
(f)(2) of this AD.
    (1) Reduce the life limits of the MLG orifice support tube 
having part number (P/N) 46117-1, upper bearing having P/N 46114-1, 
and piston plug having P/N 46137-1, by inserting Dash 8 400 Series 
(Bombardier) Temporary Revision ALI-28, dated December 11, 2003, 
into the AWL section. Thereafter, except as provided in paragraph 
(g) of this AD, no alternative life limits may be approved for the 
MLG orifice support tube, upper bearing, or piston plug.
    (2) Incorporate structural inspection tasks 712001F102 and 
712003F102 to reduce the threshold for initiating repetitive 
detailed inspections for cracking of the engine isolator brackets by 
inserting Dash 8 400 Series (Bombardier) Temporary Revision ALI-37, 
dated March 30, 2004, into the AWL section. Thereafter, except as 
provided in paragraph (g) of this AD, no alternative structural 
inspection threshold may be approved.

Alternative Methods of Compliance (AMOCs)

    (g) The Manager, New York Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.

Related Information

    (h) Canadian airworthiness directive CF-2004-19, dated September 
21, 2004, also addresses the subject of this AD.

Material Incorporated by Reference

    (i) You must use Dash 8 400 Series (Bombardier) Temporary 
Revision ALI-28, dated December 11, 2003; and Dash 8 400 Series 
(Bombardier) Temporary Revision ALI-37, dated March 30, 2004; to the 
Dash 8 400 Series (Bombardier) Maintenance Requirements Manual, to 
perform the actions that are required by this AD, unless the AD 
specifies otherwise. The Director of the Federal Register approves 
the incorporation by reference of these documents in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service 
information, contact Bombardier, Inc., Bombardier Regional Aircraft 
Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. 
To view the AD docket, go to the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, 
Nassif Building, Washington, DC. To review copies of the service 
information, go to the National Archives and Records Administration 
(NARA). For information on the availability of this material at the 
NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on June 7, 2005.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-11695 Filed 6-14-05; 8:45 am]
BILLING CODE 4910-13-P

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