Airworthiness Directive · Amendment 39-17395 · Tail rotor system
Eurocopter France Helicopters
This AD applies to Eurocopter Model AS332C, L, and L1 helicopters with a main rotor head (MRH), part number (P/N) 332A31-0001-05 or P/N 332A31-0001-06, with a serial number (S/N) M172, M216, M261, M308, M547, M561, M677, M811, M859, M935, M936, M938, or M942 installed; having less than 275 hours time-in-service (TIS) since the last overhaul of the MRH; certificated in any category.
We are adopting a new airworthiness directive (AD) for Eurocopter France (Eurocopter) Model AS332C, L, and L1 helicopters to require a one-time inspection of the main rotor head (MRH) swash-plate upper bearing (bearing) for a non-smooth point (friction point). This AD was prompted by a report of the premature deterioration of the MRH bearing of the rotating star installed on a Model AS332L1 helicopter. The actions of this AD are intended to detect deterioration of the MRH bearing and to prevent overloading the scissor links which drive the main rotor system, failure of the scissors links, and subsequent loss of control of the helicopter.
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.
Within 5 hours TIS:
(1) Inspect the MRH bearing for a non-smooth point (friction point) by rotating the MRH swash-plate and:
(i) If there is a friction point in the bearing, before further flight, replace the MRH with an airworthy MRH.
(ii) If there is not a friction point in the bearing, lubricate the MRH swash-plate and rotate it until grease is expelled; inspect the expelled grease for metal particles.
(A) If there is a metal particle in the grease, before further flight, replace the MRH with an airworthy MRH.
(B) If there is not a metal particle in the grease, measure the force required to rotate the MRH swash-plate using a spring scale attached to the pitch change rod attachment yokes.
(1) If the force to rotate the MRH swash-plate is equal to or greater than 5.5 kg, before further flight, replace the MRH with an airworthy MRH.
(2) If the force to rotate the MRH swash-plate is less than 5.5 kg, inspect the MRH swash-plate assembly for vertical play in the bearing. If there is vertical play in the bearing, before further flight, replace the MRH with an airworthy MRH.
(2) Before installing an MRH, P/N 332A31-0001-05 or P/N 332A31-001-06, with S/N M172, M216, M261, M308, M547, M561, M677, M811, M859, M935, M936, M938, or M942 on any helicopter, inspect the MRH in accordance with paragraph (e)(1) of this AD.
