Airworthiness Directive · Amendment 39-11787 · Sikorsky Aircraft Corporation (Sikorsky) Model S-76A Helicopters
Sikorsky Aircraft Corporation (Sikorsky) Model S-76A Helicopters
Model S-76A helicopters with Aero Aire Air Conditioning System, part number (P/N) S-76A-1-2, modified in accordance with Supplemental Type Certificate SH4680SW, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD) for Sikorsky Model S-76A helicopters. This AD requires inspecting the air conditioning system at specified intervals until installing a soft- start assembly retrofit kit to prevent a continuous flow of current through the soft-start resistor. This amendment is prompted by a report of overheating of the soft-start assembly. The actions specified by this AD are intended to prevent overheating of the air conditioning soft-start assembly, damage in the lower tailcone, an electrical fire, and subsequent loss of control of the helicopter.
To prevent overheating of the air conditioning soft-start control assembly, damage in the lower tailcone, a fire, and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 25 hours time-in-service (TIS) and thereafter at intervals not to exceed 25 hours TIS, inspect the soft-start control assembly in accordance with the Accomplishment Instruction, Section III, of Aero Aire Corporation Service Bulletin No. 970001, Revision A, dated September 18, 1997, except neither contact nor return of the soft-start controller unit is required.
(b) Within 120 calendar days, install a soft start assembly retrofit kit (kit), P/N 76SB001, in accordance with the Accomplishment Instructions, Section III, of Aero Aire Corporation Service Bulletin 970002, dated December 18, 1997. Installing the kit is terminating action for the requirements of this AD.
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
