AD 2017-14-06

This AD is effective August 25, 2017.

The Director of the Federal Register approved the incorporation by reference of certain documents listed in this AD as of August 25, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain other publication listed in this AD as of October 20, 1993 (58 FR 51770, October 5, 1993).

For Schweizer or Sikorsky service information identified in this final rule, contact Sikorsky Aircraft Corporation, Customer Service Engineering, 124 Quarry Road, Trumbull, CT 06611; telephone 1-800-Winged-S or 203-416-4299; email wcs_cust_service_eng.gr-sik@lmco.com. You may review a copy of the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-6968.

Blaine Williams, Aerospace Engineer, Boston Aircraft Certification Office, Engine & Propeller Directorate, 1200 District Avenue, Burlington, Massachusetts 01803; telephone (781) 238-7161; email blaine.williams@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to remove AD 93-17-13, Amendment 39-8684 (58 FR 51770, October 5, 1993) and add a new AD. AD 93-17-13 applied to Schweizer Aircraft Corporation and Hughes Helicopters, Inc. (now Sikorsky) Model TH55A, 269A, 269A-1, 269B, and 269C helicopters. AD 93-17-13 required within 30 days or 100 hours time-in-service (TIS), whichever occurs first and thereafter every 300 hours TIS, visually inspecting for cracks, machining steps, manufacturing tool marks, surface defects, and lack of cleanup during the production grinding operation. AD 93-17-13 also required installing engine and rotor tachometer markings and replacing any unairworthy driveshaft before further flight.

The NPRM published in the Federal Register on January 5, 2017 (82 FR 1267) and was prompted by a safety analysis by Sikorsky that determined the initial and recurrent inspection intervals and inspection method required by AD 93-17-13 were not adequate to detect all corrosion, pits, nicks, scratches, dents, and cracks. Accidents due to driveshaft failures continued to occur after AD 93-17-13 was issued. Therefore, the NPRM proposed to require, within 25 hours TIS and thereafter at intervals not to exceed 150 hours TIS, visually inspecting the driveshaft. If there are no cracks, corrosion, or other damage, the NPRM proposed performing a magnetic particle inspection. If there is a crack or other damage, the NPRM proposed to require replacing the driveshaft before further flight. The NPRM also proposed adding tachometer markings if not previously performed. Expanding the applicability to include Model 269C-1 helicopters was also proposed because these helicopters were not manufactured when AD 93-17-13 was issued but have the applicable driveshafts installed. Finally, the NPRM proposed to include specific part-numbered driveshafts to the applicability because Sikorsky is developing a new driveshaft that we do not expect to be subject to this AD.

We gave the public the opportunity to participate in developing this AD, but we received no comments on the NPRM.

We have reviewed the relevant information and determined that an unsafe condition exists and is likely to exist or develop on other products of these same type designs and that air safety and the public interest require adopting the AD requirements as proposed.

We consider this AD to be an interim action. The design approval holder is developing a replacement driveshaft that will address the unsafe condition identified in this AD. Once the replacement driveshaft is developed, approved, and available, we might consider additional rulemaking.

We reviewed Sikorsky 269C Helicopter Alert Service Bulletin B-307, Basic Issue, dated December 18, 2014, and Sikorsky 269C-1 Helicopter Alert Service Bulletin C1B-043, Basic Issue, dated December 18, 2014 (ASBs). The ASBs call for a one-time visual and magnetic particle inspection of the driveshaft and driveshaft assembly for damage. The ASBs advise that the driveshaft be sent to Sikorsky and replaced if damaged. The inspection is to be accomplished within 25 hours TIS or within 180 days from the ASBs' issue date, whichever comes first. Sikorsky has since revised its maintenance manual to incorporate these inspections every 150 hours TIS.

We also reviewed Schweizer Aircraft Service Bulletin B-257.1, dated May 21, 1993 (ASB B-257.1). ASB B-257.1 calls for a one-time inspection to look for drive-shaft defects; installing declutched limit markings on the engine/rotor tachometer to reinforce operating limits; and prohibiting engine declutched operations above 1600 RPM.

This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

The Sikorsky service information calls for the initial inspection to be completed within 180 days or 25 hours TIS. This AD requires that the initial inspection to be completed within 25 hours TIS only. The service information requires contacting Sikorsky if a certain part-numbered driveshaft is installed, emailing information to Sikorsky, and returning damaged parts to Sikorsky; this AD does not.

We estimate that this AD affects 619 helicopters of U.S. Registry and that labor costs average $85 per work hour. Based on these estimates, we expect the following costs:

• We estimate that the visual and magnetic particle inspections of the driveshaft requires 11 work hours for a cost of $935 per helicopter and $578,765 for the U.S. fleet per inspection cycle.

• Replacing the driveshaft, if needed, costs about $4,574 for parts. No additional labor costs are necessary.

• Installing engine and rotor tachometer markings requires 0.5 work-hour for a labor cost of about $43. The cost of parts is minimal.

We consider this AD to be an interim action. The design approval holder is developing a replacement driveshaft that will address the unsafe condition identified in this AD. Once the replacement driveshaft is developed, approved and available, we might consider additional 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.

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 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 an economic evaluation of the estimated costs to comply with this AD and placed it in the AD docket.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 93-17-13, Amendment 39-8684 (58 FR 51770, October 5, 1993) and adding the following new AD: