Airworthiness Directive · Amendment 39-17666 · Main rotor transmission mount
Eurocopter France Helicopters
This AD applies to Eurocopter France (Eurocopter) Model AS332L2 and EC225LP helicopters, certificated in any category.
We are adopting a new airworthiness directive (AD) for Eurocopter France (Eurocopter) Model AS332L2 and EC225LP helicopters. This AD requires inspecting the torque value of the bolts that secure the front and rear main gearbox (MGB) suspension bar attaching fittings, and re-torqueing the bolts to the proper value if the torque value is out of tolerance. This AD also requires, if the torque value is out of tolerance by more than 20 percent, inspecting the bolts, frames, and related equipment for a crack and repairing or replacing them if cracked. This AD was prompted by reports of cracks on Frame 5295 of Model AS332L2 helicopters. The actions of this AD are intended to detect the torque loss of the bolts that secure the MGB bar attaching fittings and to prevent cracks that could lead to failure of the MGB supporting structure, detachment of the MGB, and loss of helicopter control.
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) Within 500 hours time-in-service (TIS), and thereafter at intervals not to exceed 825 hours TIS, inspect the tightening torque of each bolt that secures the front and rear MGB attaching fitting by using as reference Figure 1 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.65, Revision 0, dated March 28, 2006, for the Model AS332L2 helicopters; and ASB No. 05A002, Revision 1, dated December 6, 2007, for the Model EC225LP helicopters.
(2) If the loss of tightening torque of a nut is less than or equal to 20 percent of the minimum tightening torque, before further flight, readjust the tightening torque.
(3) If the loss of tightening torque of any nut (front or rear) is greater than 20 percent of the minimum tightening torque, before further flight:
(i) Inspect each bolt and nut that secures the attachment fitting for a crack, and
(ii) Inspect for a crack in the attachment area of the attachment fitting, the attachment plate, and Frame 3855 for the front fitting and Frame 5295 for the rear fitting.
(A) If no crack exists, readjust the tightening torque.
(B) If there is a crack in any nut or bolt, before further flight, replace all four nuts and bolts of the affected attachment fitting.
(C) If there is a crack in the attachment area of the attachment fitting or the attachment plate, before further flight, replace the cracked attachment fitting or plate with an airworthy fitting or plate.
(D) If there is a crack in Frame 3855 for the front fitting or Frame 5295 for the rear fitting, before further flight, repair or replace the frame.
