AD 2012-20-09

We are superseding an existing airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. That AD currently requires a modification to trim the edge of the bumper plate, including performing an inspection for damage or cracks of the bumper plate and base fitting, and replacing any damaged or cracked part. That AD also currently requires, for certain airplanes, reidentifying the bumper plate. This new AD requires, for airplanes on which the reidentification is done, an operational check of the alternate extension system of the main landing gear (MLG), and repair if necessary. This AD was prompted by the determination that an operational check must be done after reidentifying the bumper plate to ensure the identified unsafe condition is addressed. We are issuing this AD to detect and correct failure of the MLG to extend and lock, which could adversely affect the safe landing of the airplane.

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 removing airworthiness directive (AD) 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011), and adding the following new AD:

2012-20-09 Bombardier: Amendment 39-17215. Docket No. FAA-2012-0724; Directorate Identifier 2012-NM-043-AD.

(a) Effective Date

This airworthiness directive (AD) becomes effective November 20, 2012.

(b) Affected ADs

This AD supersedes AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011).

(c) Applicability

This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and - 402 airplanes, certificated in any category, having serial numbers4001 through 4247 inclusive.

(d) Subject

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

(e) Reason

This AD was prompted by the determination that an operational check must be done after reidentifying the bumper plate to ensure the identified unsafe condition is

[[Page 63217]]

addressed. We are issuing this AD to detect and correct failure of the main landing gear (MLG) to extend and lock, which could adversely affect the safe landing of the airplane.

(f) Compliance

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

(g) Retained Actions for All Airplanes

Within 2,000 flight hours after September 19, 2011 (the effective date of AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011)): 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.

Note 1 to paragraphs (g) and (h) of this AD: 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 operational check fails, guidance on doing corrective actions can be found in the Bombardier Q400 Dash 8 Aircraft Maintenance Manual.

(h) Retained Actions for Airplanes Having Certain Bumper Plates

For airplanes on which a bumper plate having part number 85424082-101 or 85424082-103 is installed on which the rework specified in Bombardier Repair Drawing 8/4-54-553 has been done: Within 1,000 flight hours after September 19, 2011 (the effective date of AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011)), 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.

(i) Retained Credit for Previous Actions

This paragraph provides credit for the modification required by paragraph (h) of this AD by incorporation of Bombardier Modsum 4- 113645 if the modification was performed before September 19, 2011 (the effective date of AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011)), using Bombardier Service Bulletin 84-32- 74, dated December 23, 2009 (which is not incorporated by reference in this AD); and provided the modification is done within the compliance time specified in paragraph (h) of this AD.

(j) New Requirements of This AD: Operational Check for Airplanes on Which the Action Required by Paragraph (h) of This AD Is Done

Concurrently with doing the actions required by paragraph (h) of this AD, or within 30 days after the effective date ofthis AD, whichever occurs later: Perform an operational check of the alternate extension system of the MLG, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010. If the operational check fails, before further flight, repair in accordance with a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or the Transport Canada Civil Aviation (TCCA) (or its delegated agent).

Note 2 to paragraph (j) of this AD: If the operational check fails, guidance on doing the repair can be found in the Bombardier Q400 Dash 8 Aircraft Maintenance Manual.

(k) New Credit for Previous Actions

This paragraph provides credit for actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD, provided the operational check specified in paragraph (j) of this AD is done within the compliance time specified in paragraph (g) of this AD, or within 30 days after the effective date of this AD, whichever occurs later, using Bombardier Service Bulletin 84-32-74, dated December 23, 2009 (which is not incorporated by reference in this AD).

(l) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, New York 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, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding 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.

(m) Related Information

(1) 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.
(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; email thd.qseries@aero.bombardier.com; Internet http://www.bombardier.com.

(n) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(3) The following service information was approved for IBR on September 19, 2011 (76 FR 50403, August 15, 2011).
(i) Bombardier Service Bulletin 84-32-74, Revision A, dated May 17, 2010.
(ii) Reserved.
(4) 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; email thd.qseries@aero.bombardier.com; Internet http://www.bombardier.com.
(5) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.
(6) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/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 July 25, 2012 (77 FR 43545), and proposed to supersede AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011). That NPRM proposed to correct an unsafe condition for the specified products. 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. 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 (77 FR 43545, July 25, 2012) 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.

Costs of Compliance

Based on the service information, we estimate that this AD affects about 65products of U.S. registry.
The actions that are required by AD 2011-17-04, Amendment 39-16768 (76 FR 50403, August 15, 2011), and retained in this AD take about 8 work-hours per product, at an average labor rate of $85 per work hour. Required parts would 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, the cost of the currently required actions is $1,159 per product.
We estimate that it takes about 1 work-hour per product to comply with the new basic requirements of this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of the AD on U.S. operators to be $5,525, or $85 per product.
We have received no definitive data that would enable us to provide a cost estimate for the on-condition actions specified in this AD.

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 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;
2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
3. Will not affect intrastate aviation in Alaska; and
4. 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 atthe Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM (77 FR 43545, July 25, 2012), 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.