AD 2011-17-04

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

One in-service incident has been reported on [a] DHC-8 Series 400 aeroplane in which the right hand main landing gear (MLG) failed to extend using the alternate gear extension system. * * * Failure of [the] MLG to extend and lock could adversely affect the safe landing of the aeroplane.
* * * * *
We are issuing this AD to require actions to correct the unsafe condition on these products.

Final rule.

Adoption of the Amendment

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 AD:

2011-17-04 Bombardier, Inc.: Amendment 39-16768. Docket No. FAA- 2011-0470; Directorate Identifier 2010-NM-190-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective September 19, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, having serial numbers 4001 through 4247 inclusive.

Subject

(d) Air Transport Association (ATA) of America Code 32: Landing Gear.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:
One in-service incident has been reported on [a] DHC-8 Series 400 aeroplane in which the right hand main landing gear (MLG) failed to extend using the alternate gear extension system. * * * Failure of [the] MLG to extend and lock could adversely affect the safe landing of the aeroplane.
* * * * *

Compliance

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

Actions

(g) Within 2,000 flight hours after the effective date of this AD: Incorporate Bombardier Modsum 4-113645, including performing a detailed visual inspection for damage or cracks of the bumper plate and base fitting and replacing any damaged or cracked part, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010. Do all applicable replacements before further flight.
(h) For airplanes on whicha bumper plate having part number 85424082-101 or 85424082-103 is installed that has been reworked in accordance with Bombardier Repair Drawing 8/4-54-553: Within 1,000 flight hours after the effective date of this AD, reidentify the bumper plate, in accordance with paragraph 3.B., step (8) of the Accomplishment Instructions of Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010.

Note 1: Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010, includes an operational check of the alternate extension system of the MLG. If the check fails, guidance on doing corrective actions can be found in the Bombardier Q400 Dash 8 Aircraft Maintenance Manual.

Credit for Actions Accomplished in Accordance With Previous Service Information

(i) Incorporation of Bombardier Modsum 4-113645 before the effective date of this AD in accordance with Bombardier Service Bulletin 84-32-74, dated December 23, 2009, is considered acceptable for compliance with the modification in paragraph (h) of this AD, provided the action in paragraph (h) of this AD is done within the compliance time specified in paragraph (h) of this AD.

FAA AD Differences

Note 2: This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(j) The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the New York ACO, send it to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York, 11590; telephone 516-228- 7300; fax 516-794-5531. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.
(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

Related Information

(k) Refer to MCAI Canadian Airworthiness Directive CF-2010-23, dated July 21, 2010; and Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010; for related information.

Material Incorporated by Reference

(l) You must use Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010, to do the actions required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Bombardier, Inc., Q-Series Technical Help Desk, 123 Garratt Boulevard, Toronto, Ontario M3K 1Y5, Canada; telephone 416-375-4000; fax 416-375-4539; e-mail thd.qseries@aero.bombardier.com; Internet http://www.bombardier.com.
(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.
(4) You may also review copies of the service information that is incorporated by reference at the National Archives and

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Records Administration (NARA). For information on the availability of this material atNARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on May 12, 2011 (76 FR 27615). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

One in-service incident has been reported on [a] DHC-8 Series 400 aeroplane in which the right hand main landing gear (MLG) failed to extend using the alternate gear extension system. Investigation determined that the tread on the outboard tire was catching on the bumper plate located on the outboard MLG door that prevented the MLG door to open following an extension attempt via the alternate extension system. Failure of [the] MLG to extend and lock could adversely affect the safe landing of the aeroplane.
To prevent the potential jam condition between the bumper plate and the MLG tires, Bombardier Aerospace has developed a modification to trim the edge of the bumper plate to eliminate the possibility of interference [Bombardier Modsum 4-113645].

The Modsum includes performing a detailed visual inspection for damage or cracks of the bumper plate and base fitting and replacing any damaged or cracked part with a new part, if necessary. You may obtain further information by examining the MCAI in the AD docket.

Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

Conclusion

We reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD isclear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.
We might also have required different actions in this AD from those in the MCAI in order to follow our FAA policies. Any such differences are highlighted in a NOTE within the AD.

Costs of Compliance

We estimate that this AD will affect 65 products of U.S. registry. We also estimate that it will take about 8 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Required parts will cost about $479 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of the ADon U.S. operators to be $75,335, or $1,159 per product.

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

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products identified in this rulemaking action.

Regulatory Findings

We 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 this AD:
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 AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

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