E7-19202. Airworthiness Directives; Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) and SAAB 340B Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed 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:

A crack has been found in an axle adaptor during fatigue testing. It was found that the internal edges of the dowel holes did not have the correct radius and the crack had developed from the edge of one of the dowel holes.

A crack in the axle adaptor can cause the axle adaptor to fail and ultimately lead to loss of the wheels and total loss of brake capability.

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

DATES:

We must receive comments on this proposed AD by October 29, 2007.

ADDRESSES:

You may send comments by any of the following methods:

• DOT Docket Web Site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Federal eRulemaking Portal: http://www.regulations.gov. Follow the instructions for submitting comments.

Examining the AD Docket

You may examine the AD docket on the Internet at http://dms.dot.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 this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Mike Borfitz, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-29331; Directorate Identifier 2007-NM-136-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on 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 we receive about this proposed AD.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2006-0263, dated August 29, 2006 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

A crack has been found in an axle adaptor during fatigue testing. It was found that the internal edges of the dowel holes did not have the correct radius and the crack had developed from the edge of one of the dowel holes.

A crack in the axle adaptor can cause the axle adaptor to fail and ultimately lead to loss of the wheels and total loss of brake capability.

The corrective action includes doing repetitive ultrasonic inspections to detect cracking in the axle adaptor; replacing the axle adaptor if necessary; and ultimately doing the terminating action of inspecting and modifying the main landing gear (MLG) shock strut and axle adaptors. The inspection is a crack test. The modification includes measuring the dowel hole, and corrective actions if necessary (replacing the axle adaptor, repairing the dowel hole) and, when accomplished, terminates the repetitive inspection requirements. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Saab has issued Service Bulletin 340-32-133, Revision 01, dated May 3, 2006. APPH Limited has issued APPH Service Bulletin AIR83064-32-12, Revision 3, dated April 26, 2006; and AIR83022-32-32, Revision 3, dated April 26, 2006. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

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 is clear 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 proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a NOTE within the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 220 products of U.S. registry. We also estimate that it would take about 9 work-hours per product to comply with the basic requirements of this proposed AD. Required parts cost would be negligible. The average labor rate is $80 per work-hour. 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 proposed AD on U.S. operators to be $158,400, or $720 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 products identified in this rulemaking action.

Regulatory Findings

We 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 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. 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 and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

Saab Aircraft AB: Docket No. FAA-2007-29331; Directorate Identifier 2007-NM-136-AD.

Comments Due Date

(a) We must receive comments by October 29, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the airplanes listed in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category, unless equipped with Main Landing Gear (MLG) shock struts modified in accordance with APPH Service Bulletin AIR83064-32-12 or AIR83022-32-32.

(1) Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) airplanes, serial numbers (S/Ns) SF340A-004 through -159.

(2) Saab Model SAAB 340B airplanes, S/Ns 340B-160 through -459.

Subject

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

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

A crack has been found in an axle adaptor during fatigue testing. It was found that the internal edges of the dowel holes did not have the correct radius and the crack had developed from the edge of one of the dowel holes.

A crack in the axle adaptor can cause the axle adaptor to fail and ultimately lead to loss of the wheels and total loss of brake capability.

The corrective action includes doing repetitive ultrasonic inspections to detect cracking in the axle adaptor; replacing the axle adaptor if necessary; and ultimately doing the terminating action of inspecting and modifying the main landing gear (MLG) shock strut and axle adaptors. The inspection is a crack test. The modification includes measuring the dowel hole and corrective actions if necessary (replacing the axle adaptor, repairing the dowel hole), and, when accomplished, terminates the repetitive inspection requirements.

Actions and Compliance

(f) Unless already done, do the following actions.

(1) Within 8,000 flight cycles since the last MLG overhaul, or within 1,500 flight cycles, or 6 months after the effective date of this AD, whichever occurs latest: Inspect the MLG in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-32-133, Revision 01, dated May 3, 2006. If any crack is found, before further flight: Replace the axle adaptor in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-32-133, Revision 01, dated May 3, 2006.

(2) Repeat the inspection required by paragraph (f)(1) of this AD thereafter at intervals not to exceed 2,000 flight cycles until the terminating action required by paragraph (f)(3) of this AD is accomplished.

(3) Within 12,000 flight cycles after the effective date of this AD, or at the next MLG overhaul, whichever occurs earlier: Inspect and modify the MLG shock strut and axle adaptors in accordance with the Accomplishment instructions of APPH Service Bulletin AIR83064-32-12, Revision 3, dated April 26, 2006; or AIR83022-32-32, Revision 3, dated April 26, 2006; as applicable.

(4) Actions done before the effective date of this AD in accordance with the service bulletins listed in paragraphs (f)(4)(i), (f)(4)(ii), and (f)(4)(iii) of this AD, as applicable, are acceptable for compliance with the corresponding actions in this AD.

(i) Saab Service Bulletin 340-32-133, dated April 19, 2006.

(ii) APPH Service Bulletin AIR 83064-32-12, dated January 18, 2006; Revision 1, dated January 23, 2006; and Revision 2, dated March 30, 2006.

(iii) APPH Service Bulletin AIR83022-32-32, dated January 18, 2006; Revision 1, dated January 23, 2006; and Revision 2, dated March 30, 2006.

(5) As of the effective date of this AD, no person may install an MLG shock strut having part number (P/N) AIR83022 or 83064, or axle adaptor having P/N AIR127308, 390226, or AIR130238, unless it has been inspected and modified in accordance with APPH Service Bulletin AIR83022-32-32 or AIR83064-32-12.

FAA AD Differences

Note:

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

Other FAA AD Provisions

(g) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, ANM-116, International Branch, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Mike Borfitz, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(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.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

Related Information

(h) Refer to MCAI EASA Airworthiness Directive 2006-0263, dated August 29, 2006; Saab Service Bulletin 340-32-133, Revision 01, dated May 3, 2006; APPH Service Bulletin AIR83064-32-12, Revision 3, dated April 26, 2006; and APPH Service Bulletin AIR83022-32-32, Revision 3, dated April 26, 2006; for related information.

Issued in Renton, Washington, on September 21, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.