Airworthiness Directive · Amendment 39-21450 · Electrical power system wiring
Airbus Helicopters Deutschland GmbH (Type Certificate Previously Held by Eurocopter Deutschland GmbH) Helicopters
This AD applies to the following Airbus Helicopters Deutschland GmbH (Type Certificate previously held by Eurocopter Deutschland GmbH) helicopters, certificated in any category:
(1) Model BO-105A, BO-105C, and BO-105S helicopters with a voltage regulator part number (P/N) 51565-000, 51565-000R, or 51509-002R installed; and
(2) Model MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters.
The FAA is adopting a new airworthiness directive (AD) for Airbus Helicopters Deutschland GmbH (Airbus Helicopters) Model BO-105A, BO-105C, BO-105S, MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4, MBB- BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters. This AD was prompted by a report of a loss of electrical ground between the starter-generator and the generator voltage regulator (regulator). This AD requires inspecting the starter-generator electrical ground connection, retrofitting the starter-generator wire harness, and depending on model, revising the existing Rotorcraft Flight Manual (RFM) for your helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 50 hours time-in-service (TIS):
(i) Visually inspect the wire terminal of wire P55F16N/P56F16N for Model BO-105A, BO-105C, and BO-105S helicopters and wire 1PA53B20/2PA53B20 for Model MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters on Terminal E of each starter-generator for a crack, a kink, fraying, looseness, missing material, and corrosion. If there is a crack, a kink, fraying, looseness, missing material, or any corrosion, before further flight, replace the wire terminal.
(ii) Measure the resistance between each starter-generator and its regulator in accordance with the Accomplishment Instructions, paragraph 2.A.2.3. of Eurocopter Alert Service Bulletin ASB BO105-90-103, Revision 4, dated June 21, 2010, or paragraphs 2.A.2.3. and 2.A.2.5. of Eurocopter Alert Service Bulletin ASB-MBB-BK117-90-118, Revision 2, dated May 4, 2009, as applicable to your model helicopter. If the resistance is more than 500 milliohms, before further flight, replace the wire terminal.
(2) Within 150 hours TIS:
(i) Install a wire harness from each generator voltage regulator as follows.
(A) For Model BO-105A, BO-105C, and BO-105S helicopters: Wire harness P/N 105-90081.
(B) For Model MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, and MBB-BK 117 B-2 helicopters: Wire harness P/N 117-901941.
(C) For Model MBB-BK 117 C-1 helicopters: Wire harness P/N 117-901961.
(ii) For Model MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters, revise the existing Rotorcraft Flight Manual (RFM) for your helicopter to include the information in Section 3 Emergency and Malfunction Procedures of the following temporary revisions, as applicable to your helicopter: Eurocopter Flight Manual BK117 A-3 Temporary Revision 9, Eurocopter Flight Manual BK117 A-4 Temporary Revision 5, Eurocopter Flight Manual BK117 B-1 Temporary Revision 6, Eurocopter Flight Manual BK 117 B-2 Temporary Revision 1, or Eurocopter Flight Manual BK 117 C-1 Temporary Revision 2, all dated September 22, 2006. Using a later RFM revision with information identical to that contained in the temporary revision specified for your helicopter is acceptable for compliance with the requirement of this paragraph.
(iii) For Model MBB-BK 117 A-1 helicopters, revise Section 3 Emergency and Malfunction Procedures of the existing RFM for your helicopter to include the information in Figures 1 through 3 to paragraph (g)(2)(iii) 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.
