AD/JBK 117/23 Main Rotor Blades with Bolted Lead Inner 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.

Kawasaki BK 117 Series Helicopters

AD/JBK 117/23 Main Rotor Blades with Bolted
Lead Inner Weights 7/2005 DM

Applicability:

Model BK117, BK117 A-3, BK117 A-4, BK117 B-1, BK117 B-2, and BK117 C-1 helicopters.

Requirement:

Action in accordance with Kawasaki Service Bulletins KSB-117-248 and KSB-117-248-1, or later JCAB approved revisions.

Note:  JCAB AD No. TCD-6590-2005 refers.

Compliance:

As specified in the Requirement documents. Unless it has already been accomplished, the 4 week period for the log check begins on 6 May 2005.

This Airworthiness Directive becomes effective on 6 May 2005.

Background:

A report was received of the in-flight occurrence of severe vibrations on a BK117 helicopter.  The pilot immediately performed a safe landing.  The initial inspection revealed a cracked-open main rotor blade trailing edge.  A subsequent inspection by the manufacturer revealed that a part of a bolted lead inner weight had come loose.  This Directive introduces a life limit for blades with bolted lead inner weights installed.

David Villiers
Delegate of the Civil Aviation Safety Authority

4 May 2005