Airworthiness Directive · Amendment 39-17065 · Rotorcraft tailboom
Eurocopter Deutschland GmbH Helicopters
This AD applies to Model EC135 helicopters with a ring frame, part number (P/N) L535A3501230, installed, certificated in any category.
We are adopting a new airworthiness directive (AD) that supersedes an existing Emergency Airworthiness Directive (EAD) for certain Eurocopter Deutschland GmbH (ECD) Model EC135 helicopters. The existing EAD, which was previously sent to all known U.S. owners and operators of ECD Model EC135 helicopters and not made generally effective by publication in the Federal Register, currently requires inspecting the ring frame between the rear structure tube (tailboom) and the tail rotor fenestron housing (fenestron housing) for a crack before the first flight of each day and replacing any cracked ring frame with an airworthy ring frame. Since we issued that EAD, we have determined that a pre-flight pilot check in conjunction with a recurring 25-hour inspection is sufficient for determining the airworthiness of the ring frame. Additionally, ECD has developed a modification that is terminating action for the requirements of that EAD. This superseding AD revises the inspection requirements of the EAD to allow an owner/operator to perform the pre-flight pilot check, adds a recurring inspection of the ring frame, and allows for installation of a ring frame reinforcement as an optional terminating action for the AD requirements. The actions are intended to detect a crack in the ring frame which could result in loss of the fenestron structure 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.
(1) Before further flight, and thereafter at before the first flight of the day, visually check the ring frame that connects the tail rotor fenestron housing to the tailboom for a crack. This action 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 91.173, 121.380, or 135.439.
(2) Within 25 hours time-in-service (TIS), and thereafter at intervals not to exceed 25 hours TIS, remove the tail rotor driveshaft paneling and visually inspect the ring frame for a crack.
(3) While performing a check or an inspection as required in paragraph (f)(1) or (f)(2) of this AD, paint cracks around the rivet heads and in the transition area between the tailboom and ring frame or between the ring frame and fenestron housing may be present and do not create an unsafe condition. If you are unable to determine whether a crack is on the paint or on the ring frame, you must remove the paint to do an accurate inspection.
(4) If there is a crack in the ring frame, before further flight, replace it with an airworthy ring frame.
(5) As an optional terminating action for the requirements of this AD, you may install a frame reinforcement to the ring frame and re-identify the ring frame in accordance with the Accomplishment Instructions, paragraph 3.B. of Eurocopter EC135 Service Bulletin EC135-53-023, as corrected on November 13, 2009, except you are not required to contact ECD as noted under paragraphs 3.B.(3) Caution and 3.B.(8).
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.
