Airworthiness Directive · Amendment 39-17487 · Rotorcraft servo system
Eurocopter France Helicopters
This AD applies to Eurocopter France (Eurocopter) Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters, certificated in any category.
We are publishing a new airworthiness directive (AD) for Eurocopter France Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. This AD requires, before further flight, determining whether a single hydraulic main or tail rotor servo-control is installed on your helicopter. If a certain servo-control is installed, before the further flight, this AD requires replacing that servo-control. This AD was prompted by the discovery of excessive axial play detected on bearings installed on certain single hydraulic main and tail rotor servo-controls (servo-control). The excessive play could cause the distributor slide valve to jam in its sleeve. This condition could result in jamming the hydraulic flight controls, necessitating that the pilot cut off hydraulic power. This action would increase the pilot's workload, resulting in possible 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) Before further flight, inspect the single hydraulic main and tail servo-control's (servo-control) component history card or equivalent record to determine if it has a part number (P/N) and serial number (S/N) listed in the Appendix, paragraph 4.A, of Eurocopter Emergency Alert Service Bulletin No. 67.00.60 (EASB No. 67.00.60) or No. 67.00.41 (EASB No. 67.00.41), both dated April 15, 2013, as appropriate for your model helicopter; or was repaired or overhauled from September 27, 2012, through January 30, 2013, by UTC Aerospace Systems or Goodrich Corporation in Monroe, North Carolina.
(2) If the servo-control does have a P/N and S/N listed in paragraph 4.A of EASB No. 67.00.60 or EASB No. 67.00.41, as appropriate for your model helicopter, or if the servo-control was repaired or installed from September 27, 2012, through January 30, 2013, by UTC Aerospace Systems or Goodrich Corporation in Monroe, North Carolina, inspect the servo-control to determine whether the identification plate is marked with a “B” as shown in the Appendix, paragraph 4.B, of EASB No. 67.00.60 or EASB No. 67.00.41, as appropriate for your model helicopter. If it is marked with a “B,” no further action is required.
(3) If the identification plate is not marked with a “B,” inspect all sides of the external race of the servo-control's bearing to determine if it has any marking shown as (b) in Detail A of Figure 1 of EASB No. 67.00.60 or EASB No. 67.00.41, as appropriate for your model helicopter. If there is any marking, before further flight, replace the servo-control with an airworthy servo-control.
(4) If there is no marking on the sides of the external race, inspect each bearing sealing flange to determine if it is marked with “RWG Germany 60-5593” as shown as (d) in Detail C of Figure 2 of EASB No. 67.00.60 or EASB No. 67.00.41, as appropriate for your model helicopter. If there is “RWG Germany 60-5593” marking at least partially visible on a flange of the bearing, no further action is required.
(5) If there is no “RWG Germany 60-5593” marking at least partially visible on a flange of the bearing, before further flight, replace the servo-control with an airworthy servo-control.
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.
