2011-27669. Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive (AD) for the Sikorsky Model S-92A helicopters. This proposal would require inspecting each tail rotor blade (blade) for mislocated aluminum wire mesh in the blade skin. This proposal is prompted by the discovery that blades were manufactured with aluminum wire mesh mislocated, leaving portions of the graphite torque tube (spar) region unprotected from a lightning strike. This condition can exist in both the upper and lower blade skin airfoils. The actions specified by this proposed AD are intended to detect mislocated blade wire mesh and to prevent spar delamination, loss of the blade tip cap during a lightning strike, blade imbalance, loss of a blade, and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before December 27, 2011.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• 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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You may get the service information identified in this proposed AD from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone [phone], e-mail address [e-mail], or at http://www.sikorsky.com.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written data, views, or arguments regarding this proposed AD. Send your comments to the address listed under the caption ADDRESSES. Include the docket number “FAA-2011-1113, Directorate Identifier 2009-SW-53-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://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. 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 or signed 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).

Examining the Docket

You may examine the docket that contains the proposed AD, any comments, and other information 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 Docket Operations office (telephone [phone]) is located in Room W12-140 on the ground floor of the West Building at the street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

Discussion

This document proposes adopting a new AD for the Sikorsky Model S-92A helicopters. This proposal would require inspecting each blade for mislocated aluminum wire mesh in the blade skin. This proposal is prompted by the discovery that blades were manufactured with aluminum wire mesh mislocated, leaving portions of the graphite torque tube (spar) region unprotected from a lightning strike. This condition can exist on both the upper and lower blade skin airfoils. The actions specified by this proposed AD are intended to detect mislocated blade wire mesh to prevent spar delamination and loss of the blade tip cap during a lightning strike leading to blade imbalance, loss of a blade, and subsequent loss of control of the helicopter.

We have reviewed Sikorsky Special Service Instructions SSI No. 92-021A, dated October 21, 2009 (SSI), which specifies inspecting the blade for mislocated blade wire mesh. Two options are identified in the SSI. One option is to conduct an eddy current inspection and the other option is to conduct a visual inspection after sanding to determine if there is mislocated wire mesh.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, the proposed AD would require inspecting each blade to determine if the wire mesh is mislocated and replacing the blade with an airworthy blade if the wire mesh is mislocated. The actions would be required to be done by following the service information described previously.

We estimate that this proposed AD would affect 44 helicopters of U.S. registry. There are 486 suspect blades worldwide, and we assume 29 percent (141) of those blades may be on helicopters of U.S. registry. We estimate that inspecting a blade for mislocated wire mesh would take about 4 work hours per blade, assuming all operators opt to do the blade sanding inspection rather than the eddy current inspection, at an average labor rate of $85 per work hour. Required parts would cost about $13,000 for each blade repaired by the manufacturer or $180,000 for each new blade. The total cost of the proposed AD for U.S. operators would be $3,215,940, assuming 51 blades are found with mislocated wire mesh, and assuming 36 of those blades are replaced with blades repaired by the manufacturer and 15 blades are replaced with new blades.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, 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);

3. Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction; 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 draft economic evaluation of the estimated costs to comply with this proposed AD. See the AD docket to examine the draft 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
• Incorporation by reference
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

Sikorsky Aircraft Corporation: Docket No. FAA-2011-1113; Directorate Identifier 2009-SW-53-AD.

Applicability: Model S-92A helicopters, tail rotor blade assembly (blade), part numbers (P/N) 92170-11000-044, -045, and -046, with a serial number with a prefix of “A111” and a number equal to or less than “-00585,” installed, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To detect mislocated blade wire mesh and to prevent spar delamination, loss of the blade tip cap during a lightning strike, blade imbalance, loss of a blade, and subsequent loss of control of the helicopter, do the following:

(a) Within 60 days, inspect the upper and lower airfoils of each tail rotor blade to determine if the wire mesh is mislocated.

(1) Inspect by using either an eddy current inspection in accordance with paragraphs B.(1)(a) through B.(1)(o) or using the hand-sanding method and visually inspecting in accordance with paragraphs B.(2)(a) through B.(2)(d) of Sikorsky Special Service Instructions SSI No. 92-021A, Revision A, dated October 21, 2009, except you are not required to contact or report nonconforming blades to the manufacturer. If you sand and visually inspect and confirm the correct location of the wire mesh, touch-up and repaint the sanded area.

(2) If there is a blade with a mislocated wire mesh, before further flight, replace the blade with an airworthy blade.

(b) 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: Nicholas Faust, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

(c) The Joint Aircraft System/Component (JASC) Code is 6410, Tail Rotor Blades.

Issued in Fort Worth, Texas, on October 7, 2011.

Lance T. Gant,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.