Applicability: Model BK 117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and BK117C-1 helicopters.

Requirement:

1. Revise the KHI-BK117 Maintenance Manual to Revision No. 14 (or later approved revision) for Models KHI-BK 117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and Revision No. 2 (or later approved revision) for Model KHI-BK117C-1.
2. Perform the inspections detailed in KSB-117-129C in accordance with the inspection interval and method specified in the KHI-BK117 Maintenance Manual, revised by Requirement 1. If the inspection results exceed the allowable limit specified in the KHI-BK117 Maintenance Manual, before further flight, contact KHI Customer Service for technical advice.

Note 1: Kawasaki Service Bulletin No. KSB-117-129C refers.

Note 2: JCAB AD TCD-4605B-2006 refers.

Compliance: Initially, before further flight after 28 March 2006. Thereafter as specified in Requirement 2. This Amendment becomes effective on 28 March 2006.

Background: A report was received of a fatal accident overseas where investigation revealed that the tail boom vertical fin had failed as a result of a fatigue crack that initiated on the left side of the vertical fin spar cap, and propagated across the cap and the web. Amendment 1 required a reinforcement modification, while still requiring a repetitive inspection at increased periodicity. Amendment 2 introduced the latest revision of the Requirement document which revised the modification procedures. Amendment 3 is issued in response to a new JCAB AD, which transfers the inspection requirements of this Directive to the KHI-BK117 Maintenance Manual. The original issue of this Airworthiness Directive became effective on 9 May 1997.

FMI: www.casa.gov.au