AD 2019-13-05 Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

This AD is effective August 29, 2019.

(1) The Manager, Boston ACO Branch, FAA, may approve AMOCs for this AD. Send your proposal to: Kristopher Greer, Aviation Safety Engineer, Boston ACO Branch, Compliance and Airworthiness Division, 1200 District Avenue, Burlington, Massachusetts 01803; telephone (781) 238-7799; email Kristopher.Greer@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, the FAA suggests that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.

Sikorsky Alert Service Bulletin (ASB) 92-53-008, Basic Issue, dated June 13, 2012; ASB 92-53-009, Basic Issue, dated December 6, 2012; ASB 92-53-012, Basic Issue, dated February 10, 2014, Sikorsky Special Service Instructions No. 92-074-E, Revision E, dated April 9, 2014, and Sikorsky S-92A-AMM-000 Maintenance Manual, Chapter 53-20-00, Task 53-20-00-210-003, “Inspection of Main Transmission Airframe Support Structure,” dated November 30, 2018, which are not incorporated by reference, contain additional information about the subject of this AD. For service information identified in this AD, 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 view this information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177.

(1) For helicopters with a frame assembly with a part number shown in Figure 1 to paragraphs (a) and (e) of this AD or Figure 2 to paragraphs (a) and (e) of this AD, before further flight, remove from service any part that has reached or exceeded its new life limit. Forward STA 328 frame assemblies that are altered and changed to P/N 92070-20124-064, 92070-20124-067, 92070-20127-045, 92070-20124-065, 92070-20124-047, or 92070-20127-046 must be removed from service upon accumulating 28,500 hours time-in-service (TIS) total (regardless of P/N) from the original frame part number initial service date. (2) For each frame assembly listed in Figure 1 to paragraphs (a) and (e) of this AD or Figure 4 to paragraphs (a) and (e)(2) of this AD with 1,801 or more hours TIS, and for each frame assembly listed in Figure 2 to paragraphs (a) and (e) of this AD or Figure 3 to paragraphs (a) and (e)(2) of this AD with 1,301 or more hours TIS, within 150 hours TIS and thereafter at intervals not to exceed 150 hours TIS, do the following inspections. For guidance on performing these inspections, refer to Sikorsky S-92A-AMM-000 Maintenance Manual Chapter 53-20-00, Task 53-20-00-210-003, “Inspection of Main Transmission Airframe Support Structure,” dated November 30, 2018. (i) Inspect the STA 328 frame and STA 362 frame between the left and right butt line (BL) 16.5 beams and inspect the area on the left and right BL 16.5 beams six inches on either side of the mounting pads for a crack and loose fasteners. If there is a loose fastener or a crack, repair or replace any cracked part and any loose fastener before further flight. (ii) Inspect the STA 328 and STA 362 outboard frames, left and right sides, from the BL 16.5 beam to water line 252.25 for a crack and loose fasteners. If there is a loose fastener or a crack, repair or replace any cracked part and any loose fastener before further flight.

This AD defines the unsafe condition as a crack in a main transmission airframe support structure. This condition could result in failure of a main transmission frame and subsequent loss of control of the helicopter.