Airworthiness Directive · Amendment 39-19678 · Fuselage main, frame
Sikorsky Aircraft Corporation Helicopters
This AD applies to Sikorsky Aircraft Corporation Model S-92A helicopters, certificated in any category, with a forward station (STA) 328 or aft STA 362 frame assembly with a part number (P/N) as shown in Figure 1 to paragraphs (a) and (e) of this AD, Figure 2 to paragraphs (a) and (e) of this AD, Figure 3 to paragraphs (a) and (e)(2) of this AD, or Figure 4 to paragraphs (a) and (e)(2) of this AD.
The FAA is adopting a new airworthiness directive (AD) for certain Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This AD was prompted by fatigue analysis indicating stress concentrations, as well as the discovery of a helicopter with a crack in the station (STA) 362 frame and skin. This AD requires inspecting the main transmission forward and aft frame assemblies and adjacent skins for a crack and loose fasteners, and establishing life limits for certain frame assemblies. The FAA is issuing this AD to address the unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
