Summary
This document proposes adopting a new airworthiness directive (AD) for the specified model Eurocopter France (ECF) helicopters. This proposal would require replacing the main gearbox (MGB) opening neoprene cowling seals (seals) with airworthy glass/silicone seals. This proposal is prompted by the discovery that neoprene seals currently installed on the MGB opening cowlings do not provide the fire protection required by the airworthiness standards. The actions specified by this proposed AD are intended to require installation of fire-resistant seals to prevent a fire in the engine compartment from reaching the MGB compartment that contains parts that are not fire resistant and subsequent loss of control of the helicopter.