E6-12305. Airworthiness Directives; Sikorsky Aircraft Corporation Model S-92A Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) for the Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This action requires, before further flight, replacing a certain main gearbox (MGB) upper main housing assembly (housing assembly) that has 2700 or more hours time-in-service (TIS) with an airworthy part. This action also requires, before further flight, revising the Airworthiness Limitations section (ALS) of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 hours TIS. This amendment is prompted by testing of the MGB housing assembly that resulted in premature fatigue failure due to a manufacturing process creating an oxide skin defect in the housing. The actions specified in this AD are intended to prevent fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter.

DATES:

Effective August 16, 2006.

Comments for inclusion in the Rules Docket must be received on or before October 2, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this 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: [phone]; or
• 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.

Examining the Docket

You may examine the docket that contains the AD, any comments, and other information on the Internet at http://dms.dot.gov,, or in person at the Docket Management System (DMS) Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

FOR FURTHER INFORMATION CONTACT:

Wayne Gaulzetti, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

This amendment adopts a new AD for the Sikorsky Model S-92A helicopters. This action requires, before further flight, replacing a certain MGB housing assembly that has 2700 or more hours TIS with an airworthy MGB housing assembly with less than 2700 hours TIS. Also, this action requires, before further flight, revising the ALS of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 or more hours TIS. This amendment is prompted by component fatigue testing of the MGB housing assembly that resulted in premature fatigue failure due to a manufacturing process creating an oxide skin defect in the housing. This condition, if not corrected, could result in fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, this AD is being issued to prevent fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter. This AD requires, before further flight, replacing any MGB housing assembly, part number 92351-15110-042, that has 2700 or more hours TIS with an airworthy part. This AD also requires, before further flight, revising the ALS of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 hours TIS.

The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability or structural integrity of the helicopter. Some operators may have already exceeded the 2700 hours TIS. Therefore, replacing each MGB housing assembly that has 2700 or more hours TIS with an airworthy MGB housing assembly is required before further flight and this AD must be issued immediately.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

We estimate that this AD will affect 13 helicopters, and will take about 20 work hours to replace the MGB housing assembly at an average labor rate of $80 per work hour. Required parts will cost about $152,000 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $1,996,800.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2006-25444; Directorate Identifier 2006-18-SW-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 AD. Using the search function of our docket Web site, you can find and read the comments to any of our dockets, including the name of the individual who sent the comment. 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.

Regulatory Findings

We have 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 the 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 an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the economic evaluation.

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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

2006-15-19 Sikorsky Aircraft Corporation: Amendment 39-14700. Docket No. FAA-2006-25444; Directorate Identifier 2006-SW-18-AD.

Applicability

Model S-92A helicopter, with main gearbox (MGB) upper main housing assembly (housing assembly), part number 92351-15110-042, installed, certificated in any category.

Compliance

Required as indicated, unless accomplished previously.

To prevent fatigue failure of the MGB housing, loss of MGB lube oil, loss of main and tail rotor drive, and subsequent loss of control of the helicopter, do the following:

(a) Before further flight, replace each MGB housing with 2700 or more hours time-in-service (TIS) with an airworthy MGB housing with less than 2700 hours TIS.

(b) This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a new retirement life for the MGB housing assembly of 2700 hours TIS.

(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Boston Aircraft Certification Office, FAA, ATTN: Wayne Gaulzetti, Aviation Safety Engineer, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

(d) This amendment becomes effective on August 16, 2006.

Issued in Fort Worth, Texas, on July 26, 2006.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.