Ad/GBK 117/18 Amdt 1 - Tail Rotor System - Control Lever - Inspection/Replacement (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/GBK 117/18 and issues the following AD under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Eurocopter BK 117 Series Helicopters

AD/GBK 117/18 Amdt 1 Tail Rotor System - Control Lever - Inspection/Replacement 11/2007 DM

Applicability:

MBB-BK 117C-2 helicopters fitted with a Tail Rotor Control Lever Part Number (P/N) B642M1009103.

Requirement:

1.    Visually inspect the control lever, in accordance with section 3.A of the accomplishment instructions of EUROCOPTER DEUTSCHLAND Alert Service Bulletin (ASB) MBB BK117 C-2-64A-002 Revision 02 dated 6 August 2007 or subsequent EASA approved revision.

2.    Repeat the inspection as specified in Requirement 1 of this AD.

3.    If, during any of the inspections detailed in Requirement required by this AD, score marks, notching, scratching, cracks or similar damage is detected, replace the affected control lever with an airworthy part.

4.    Replace all P/N B642M1009103 Tail Rotor Control Levers and Weights P/N B642M1011202 with the improved P/N B642M1009104 Tail Rotor Control Levers including weights in accordance with section 3.B of the accomplishment instructions of EUROCOPTER Deutschland ASB MBB BK117 C-2-64A-002 Revision 02.

After installation of a P/N B642M1009104 Tail Rotor Control Lever Assembly on any helicopter as detailed in Requirement 4 of this AD, the repetitive inspections detailed in Requirement 2 of this AD are no longer required.

5.    Do not install a P/N B642M1009103 Tail Rotor Control Lever on any helicopter.

Note:  EASA AD 2007-0237 dated 31 August 2007 refers. This AD supersedes EASA AD 2007-0189 E.

Compliance:

1.    For helicopters that have not been inspected as required by the original issue of this AD, before further flight after the effective date of this AD, unless previously accomplished.

For helicopters that have been inspected as required by the original issue of this AD, within the next 8 Flight Hours (FH) or before accumulating 25 FH after the last inspection as required by this AD, whichever occurs first after the effective date of this AD.

2.    At intervals not to exceed 8 FH, until replacement of the parts as detailed in Requirement 4 of this AD is made.

3.    Before further flight after the effective date of this AD.

4.    Before 25 November 2007.

5.    From 25 November 2007.

This Amendment becomes effective on 11 September 2007.

Background:

EASA was informed by the manufacturer of an in-flight incident in which a dynamic weight broke off the control lever subsequently leading to considerable vibrations.  A visual inspection revealed that the threaded bolt of the control lever had broken off. For this reason, the manufacturer issued ASB MBB BK117 C-2-64A-002 to introduce a corresponding visual inspection.

EASA subsequently issued Emergency AD 2006-0379-E to require operators to accomplish the inspection.  The aim of that EAD was to prevent separation of dynamic weights in flight, which can lead to severe vibration and reduced controllability of the helicopter.

This amendment mandates the replacement of certain parts and provides terminating action to the repetitive inspections detailed in this AD.

The original issue of this AD became effective on 30 August 2007.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

6 September 2007