Summary
We propose to adopt a new airworthiness directive (AD) for the specified Eurocopter France (ECF) model helicopters. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The aviation authority of France, with which we have a bilateral agreement, states in the MCAI:
This Airworthiness Directive (AD) is issued following two cases of LH hydraulic power system loss on two AS332 helicopters. In both cases, the pilot received the "low level'' hydraulic failure alarm. The investigations conducted on the two helicopters revealed a hydraulic fluid leak from the hydraulic pump casing. In both cases, incorrect position of the liner of the compensating piston had caused the seals to deteriorate. This incorrect positioning of the liner is due to non-compliant application of the repair process by a repair station. Deterioration of hydraulic pumps causes:
--The loss of the RH and LH hydraulic power systems in the event of a substantial hydraulic fluid leak from both hydraulic pumps during a given flight. --The loss of the hydraulic system concerned, in the event of a substantial hydraulic fluid leak from only one pump.
The proposed AD would require actions that are intended to address this unsafe condition.