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Proposed Rule

Airworthiness Directives; Bombardier Model DHC-8-400, -401, and -402 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400, -401, and -402 airplanes. This proposed AD would require revising the Start Printed Page 17355Airworthiness 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 proposed 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 proposing 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:

We must receive comments on this proposed AD by May 6, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
  • By fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-20860; the directorate identifier for this docket is 2005-NM-043-AD.

Start Further Info

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.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-20860; Directorate Identifier 2005-NM-043-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of our docket website, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

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 DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier Model DHC-8-400, -401, and -402 airplanes. TCAA advises that, during type certification fatigue testing, fatigue failures were discovered 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. The development of cracks in these principal structural elements, if not prevented, 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.

Relevant Service Information

Bombardier has issued the following temporary revisions (TRs) to the Dash 8 Series 400 (Bombardier) Maintenance Requirements Manual, PSM 1-84-7:

  • Dash 8 Series 400 (Bombardier) TR ALI-28, dated December 11, 2003; and
  • Dash 8 Series 400 (Bombardier) TR ALI-37, dated March 30, 2004

TR ALI-28 describes procedures for reducing 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. TR ALI-37 describes procedures for incorporating certain structural inspection tasks to reduce the threshold for initiating repetitive detailed inspections for cracking of the engine isolator brackets. The TCAA mandated the TRs and issued Canadian airworthiness directive CF-2004-19, dated September 21, 2004, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

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, the TCAA has kept the FAA informed of the situation described above. We have examined the TCAA's findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require revising the Airworthiness Limitation section of the Instructions for Continued Airworthiness of the Dash 8 Series 400 (Bombardier) Maintenance Requirements Manual, PSM 1-84-7, to reduce the life limits of the MLG orifice Start Printed Page 17356support 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 would require accomplishing the actions specified in the TRs described previously.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Costs of Compliance

There are about 93 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 21 airplanes of U.S. registry. The proposed actions would 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 proposed 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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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 proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

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

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

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

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

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by May 6, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-400, -401, and -402 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 Series 400 (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 a copy of the Dash 8 Series 400 (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 a copy of the Dash 8 Series 400 (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.

Start Signature

Issued in Renton, Washington, on March 30, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-6764 Filed 4-5-05; 8:45 am]

BILLING CODE 4910-13-P