Airworthiness Directive · Amendment 39-17254 · Main rotor head
Eurocopter Deutschland GmbH Helicopters
Superseded. A later AD replaced this one: AD 2014-16-24. Comply with the one in force.
This AD applies to Model EC135 P1, EC135 P2, EC135 P2+, EC135 T1, EC135 T2, and EC135 T2+ helicopters, with a main rotor hub (MRH) shaft, part number (P/N) L623M1006101, L623M1206101, L623M1006102, L623M1206102, L623M1006103, or L623M1206103 installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Eurocopter Deutschland GmbH (ECD) Model EC135 P1, EC135 P2, EC135 P2+, EC135 T1, EC135 T2, and EC135 T2+ helicopters. This is the Federal Register publication of an Emergency AD (EAD) that was previously sent to all known owners and operators of these helicopters. That EAD superseded an earlier related EAD. This AD requires, before further flight and at specified intervals, checking and inspecting the upper and lower main rotor hub (MRH) shaft flanges for a crack, and inspecting the lower hub-shaft flange bolt attachment areas for a crack. This AD is prompted by three reported incidents of cracking on the lower hub-shaft flanges of EC135 model helicopters. These actions are intended to detect a crack on the hub-shaft flange, which if not corrected could result in failure of the MRH and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time.
(1) Before further flight, and thereafter at intervals not to exceed 6 hours time-in-service (TIS), check the MRH shaft lower flange and the visible area of the MRH shaft upper flange for a crack. Figures 1 and 2 to Paragraph (f)(1) of this AD are examples of cracks that have been discovered in the MRH shaft lower flange. The actions required by this paragraph may be performed by the owner/operator (pilot) holding at least a private pilot certificate, and must be entered into the aircraft records showing compliance with this AD in accordance with 14 CFR 43.9 (a)(1)-(4) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439.
(2) For MRH shafts with 400 or more hours TIS, within 10 hours TIS, and thereafter at intervals not to exceed 10 hours TIS:
(i) Remove rotor-hub cap.
(ii) Clean the upper and lower MRH shaft flange as depicted in Figure 3 to Paragraph (f)(2)(ii) of this AD and visually inspect for a crack.
(iii) Remove the safety pins and nut from each blade bolt and the washers from the lower MRH shaft flange.
(iv) Clean the blade bolt attachment area.
(v) Using a 10X or higher power magnification, inspect all lower MRH shaft flange blade bolt attachment areas for a crack as shown in Figure 4 to Paragraph (f)(2)(v) of this AD.
(3) If there is a crack in the upper or lower MRH shaft flange, before further flight, replace the MRH shaft. Replacing the MRH shaft with an MRH shaft having a part number listed in the applicability of this AD does not constitute terminating action for the requirements of this AD.
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.
