Airworthiness Directive · Amendment 39-17101 · Starter generator
Eurocopter Deutschland GmbH Helicopters
This AD applies to Model MBB-BK 117 C-2 helicopters, certificated in any category.
We are superseding an existing airworthiness directive (AD) for all Eurocopter Deutschland GmbH (ECD) Model MBB-BK 117 C-2 helicopters. That AD currently requires revising the "Emergency and Malfunction Procedures" and "Performance Data" sections of the Rotorcraft Flight Manual (RFM) by inserting three temporary pages into the RFM to alert pilots to monitor the power display when a generator is deactivated and provides procedures to prevent failure of the remaining generator. Before we issued that AD, the manufacturer developed a procedure to modify the two "After Junction Boxes" by removing a diode from each box, which provides terminating action for our AD requirements. These actions are intended to require implementing this terminating action to prevent an electrical power system failure and subsequent loss of control of the helicopter and revising the RFM accordingly, by removing the temporary pages inserted to comply with the superseded AD.
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 30 days:
(1) Remove the specified temporary pages from the following sections of the rotorcraft flight manual (RFM) RFM BK 117 C-2:
(i) “Emergency and Malfunction Procedures”: pages 3-3 and 3-4, and
(ii) “Performance Data”: page 5-7.
(2) Remove diodes CR10007 and CR10008 from the generator relays in the left-hand and right-hand After Junction Boxes, respectively, in accordance with the Accomplishment Instructions, paragraphs 3.B.2.(a) through 3.B.2.(d), and as depicted in Figures 1 and 2, of Eurocopter Alert Service Bulletin ASB MBB BK117 C-2-24A-008 Revision 1, dated August 29, 2011.
(3) Test the DC Power system for proper operation.
(4) Do not install an After Junction Box on any helicopter, unless the After Junction Box has been modified in accordance with 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.
