AD/GBK 117/16 Tail Rotor Control Lever with Weights (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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 117/16 Tail Rotor Control Lever with Weights 3/2007

Applicability:

Model BK117 C2 helicopters, serial number 9075 and subsequent, and those helicopters with serial numbers 9004 through 9074, on which Eurocopter Deutschland Service Bulletin No. MBB BK117 C-2-67-006 has been accomplished; and with a tail rotor control lever B642M1009103 installed.

Requirement:

1.    Perform a visual inspection of the tail rotor control lever in accordance with the Accomplishment Instructions of Eurocopter Deutschland Alert Service Bulletin No. MBB BK117 C-2-64A-002 original issue, or later EASA approved revision.

2.    If no score marks, notching, scratches, or cracking is detected during the initial inspection, repeat the Requirement 1 inspection.

If, during any inspection, score marks, notching, or scratches are detected that exceed the maintenance manual limits, or cracking is detected, before further flight, replace the control lever with a serviceable control lever.

Note:  EASA AD 2006-0379-E refers.

Compliance:

1.    Unless already accomplished, before further flight after 15 March 2007.

2.    Within 10 flight hours after the initial inspection, and thereafter at intervals not to exceed 25 flight hours.

This Airworthiness Directive becomes effective on 15 March 2007.

Background:

The EASA received a report of an in-flight incident in which a dynamic weight broke off the tail rotor control lever, resulting in considerable vibrations.  Inspection revealed that the threaded bolt of the control lever had broken off.  Such damage can lead to severe vibration and reduced controllability of the helicopter.

David Villiers
Delegate of the Civil Aviation Safety Authority

1 February 2007