AD 2017-02-51

This AD becomes effective March 20, 2017 to all persons except those persons to whom it was made immediately effective by Emergency AD 2017-02-51 issued on January 13, 2017, which contains the requirements of this AD. We must receive comments on this AD by May 2, 2017.

You may send comments by any of the following methods:

• Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your comments electronically.

• Fax: 202-493-2251.

• Mail: Send comments to the U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.

• Hand Delivery: Deliver to the “Mail” address between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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.

This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments prior to it becoming effective. However, we invite you to participate in this rulemaking by submitting written comments, data, or views. We also invite comments relating to the economic, environmental, energy, or federalism impacts that resulted from adopting this AD. The most helpful comments reference a specific portion of the AD, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should send only one copy of written comments, or if comments are filed electronically, commenters should submit them only one time. We will file in the docket all comments that we receive, as well as a report summarizing each substantive public contact with FAA personnel concerning this rulemaking during the comment period. We will consider all the comments we receive and may conduct additional rulemaking based on those comments.

On November 16, 2016, we issued Emergency AD 2016-24-51 to correct an unsafe condition on Sikorsky Model S-92A helicopters with a TR pitch change shaft (TRPCS) assembly, part number (P/N) 92358-06303-041 or P/N 92358-06303-042, with bearings that were manufactured prior to November 3, 2016. AD 2016-24-51 subsequently published in the Federal Register as a final rule (81 FR 95425, December 28, 2016). AD 2016-24-51 requires removing from service TRPCS assemblies with less than 5 hours time-in-service (TIS) since new or overhaul. For TRPCS assemblies with between 5 and 80 hours TIS since new or overhaul, AD 2016-24-51 also requires performing one-time inspections of the TRPCS bearings and replacing the TRPCS assembly if the bearings do not pass these inspections. AD 2016-24-51 was prompted by two reports of an operator losing TR control caused by a failed TRPCS assembly.

After AD 2016-24-51 was issued, we received a report of an S-92A helicopter losing TR control because of a failed bearing with more than 80 hours TIS. We have now determined that the unsafe condition can exist on TRPCS bearings regardless of hours TIS. Therefore, on January 13, 2017, we issued Emergency AD 2017-02-51, which applies to all TRPCS assemblies, regardless of hours TIS. Emergency AD 2017-02-51 requires a one-time visual inspection and a repetitive borescope inspection of the TRPCS assembly bearing. The repetitive inspection is intended to detect bearing deterioration. The actions in Emergency AD 2017-02-51 are intended to detect a binding bearing, prevent loss of TR control, and possible loss of control of the helicopter.

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other helicopters of the same type design.

We reviewed Sikorsky Alert Service Bulletin 92-64-011, Basic Issue, dated January 10, 2017 (ASB). The ASB describes procedures for inspecting the TRPCS and bearing assemblies for ratcheting, binding, and rough turning. The ASB also specifies periodic review of the health and usage monitoring system (HUMS) tail gearbox bearing energy tool.

This AD requires, before further flight, removing the TRPCS assembly and inspecting the bearing. If the bearing does not rotate freely; the bearing sounds rough or chatters; there is any purged grease with metal particles; a nick or dent; or if there is a cut, tear, or distortion in the bearing seal, before further flight, replacing the TRPCS assembly is required. This AD also requires, within 10 hours TIS, and thereafter at intervals not to exceed 10 hours TIS, inspecting the TRPCS assembly with a borescope. If the white Teflon seal or snap ring is missing, or if there is a rip, tear, or heat damage on the seal or if there is no gap in the snap ring, replacing the TRPCS assembly is required before further flight.

This AD requires repetitive borescope inspections of the TRPCS; the ASB does not. The ASB specifies that operators review HUMS data in addition to the one-time inspection and specifies contacting Sikorsky if any discrepancies are found; this AD does not.

We estimate that this AD will affect 80 helicopters of U.S. Registry.

We estimate that operators may incur the following costs in order to comply with this AD. At an average labor rate of $85 per hour, borescope and visually inspecting the TRPCS assembly will require 16 work-hours, for a cost per helicopter of $1,360 and a cost of $108,800 for the U.S. fleet per inspection. If required, replacing a TRPCS assembly will require 16 work-hours and required parts will cost $4,000, for a cost per helicopter of $5,360.

Providing an opportunity for public comments prior to adopting these AD requirements would delay implementing the safety actions needed to correct this known unsafe condition. Therefore, we found and continue to find that the risk to the flying public justifies waiving notice and comment prior to the adoption of this rule because the previously described unsafe condition can result in loss of TR control and certain actions must be accomplished before further flight and within 10 hours TIS, a very short interval for these helicopters.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comments before issuing this AD were impracticable and contrary to public interest and good cause existed to make the AD effective immediately by Emergency AD 2017-02-51, issued on January 13, 2017, to all known U.S. owners and operators of these helicopters. These conditions still exist and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

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.

We 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, 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 adding the following new airworthiness directive (AD):