Airworthiness Directives; Short Brothers Model SD3-60 SHERPA, SD3-SHERPA, and SD3-60 Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Short Brothers Model SD3-60 and SD3-SHERPA airplanes. The existing AD currently requires an inspection of the fork end of the rear pintle pin on each main landing gear (MLG) to verify that sealant is properly applied and is undamaged, and related investigative/corrective actions if necessary. This proposed AD would add an inspection for correctly applied sealant on the MLG rear pintle pin assemblies, and related investigative/corrective actions if necessary. This proposed AD would also expand the applicability of the existing AD. This proposed AD results from a new report of a cracked pintle pin fork end. We are proposing this AD to prevent stress-corrosion cracking and subsequent failure of the MLG.

DATES:

We must receive comments on this proposed AD by December 9, 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.
• 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.

Contact Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2125; fax (425) 227-1149.

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 in the ADDRESSES section. Include the docket number “Docket No. FAA-2005-22875; Directorate Identifier 2005-NM-179-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 received 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 that web site, 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 may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may 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 Docket Management System receives them.

Discussion

On January 25, 1993, we issued AD 93-02-03, amendment 39-8485 (58 FR 7983, February 11, 1993), for all Short Brothers Model SD3-60 and SD3-SHERPA airplanes. That AD requires an inspection of the fork end of the rear pintle pin on each main landing gear (MLG) to verify that sealant is properly applied and is undamaged; removal of the bushings and an inspection to detect faults of the bores in the fork end, if necessary; and repair of the fork end of the pintle pin, if necessary. That AD resulted from a report of a cracked fork end of the MLG rear pintle pin. We issued that AD to prevent stress-corrosion cracking and subsequent failure of the MLG.

Actions Since Existing AD Was Issued

Since we issued AD 93-02-03, we have learned about another incident of a cracked pintle pin fork end on a Model SD3 airplane.

Relevant Service Information

Shorts has issued Service Bulletins SD360 Sherpa-32-4 (for Model SD3-60 SHERPA airplanes), SD3 Sherpa-32-5 (for Model SD3-SHERPA airplanes), and SD360-32-37 (for Model SD3-60 airplanes), all dated July 2004. The service bulletins describe procedures for an inspection to determine whether sealant has been properly applied on the MLG rear pintle pin assemblies, and related investigative/corrective actions for missing or damaged sealant. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, mandated the service information and issued British airworthiness directive G-2004-0022, dated August 25, 2004, to ensure the continued airworthiness of these airplanes in the United Kingdom.

The service bulletins refer to Messier Dowty Service Bulletin 32-70SD, Revision 1, dated July 3, 1995, as an additional source of service information for the inspection and related investigative/corrective actions.

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in the United Kingdom 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 CAA has kept the FAA informed of the situation described above. We have examined the CAA's findings, evaluated all pertinent information, and determined that AD action is necessary for airplanes of this type design that are certificated for operation in the United States.

This proposed AD would supersede AD 93-02-03 and would retain the requirements of the existing AD. This proposed AD would also expand the applicability for the actions specified in service information described previously, except as discussed below.

Difference Between the Proposed AD and Service Information

The service information specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions using a method that we or the CAA (or its delegated agent) approve. In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair we or the CAA approve would be acceptable for compliance with this proposed AD.

Clarification of Inspection Terminology

In this proposed AD, the inspection specified in the service bulletins is referred to as a “general visual inspection.” Note 1 in this proposed AD defines this type of inspection.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed 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 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 and placed it in the AD docket. 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
• 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.