AD/GBK 117/6 Amdt 5 Main Rotor Blade (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 117/6 Amdt 4 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 117/6 Amdt 5 Main Rotor Blade 11/2008 DM

Applicability:

Models MBB-BK117A-1, A-3, A-4, B-1, B-2, and C-1, all serial numbers, if equipped with MR Blades as identified by Part Number (P/N) in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) ASB-MBB-BK117-10-108 Revision 3 or later revision.

Requirement:

1.    Inspect the affected MR blades in accordance with the instructions contained in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) ASB-MBB-BK117-10-108 Revision 3 or later revision.

Inspections and corrective actions accomplished prior to the effective date of this AD, in accordance with ECD ASB-MBB-BK117-10-108 at original issue or Revision 1 or Revision 2, are acceptable to comply with the initial requirements of paragraph (1) of this AD.  After the effective date of this AD, repetitive inspections and corrective actions must be accomplished in accordance with ECD ASB-MBB-BK117-10-108 at Revision 3.

During any inspection required by this AD, if damage is detected that is outside the allowable limits as specified in Eurocopter Deutschland GmbH Alert Service Bulletin (ASB) ASB-MBB-BK117-10-108 Revision 3 or later revision, contact ECD customer service to request instructions for corrective action.

Replacement of all MR blades on a helicopter with MR blades that are not fitted with lead balance weights (i.e. blade P/N not listed in ASB-MBB-BK117-10-108 Revision 3), constitutes terminating action for the requirements of this Airworthiness Directive.  After installation of blades without lead balance weights, re-fitment of blades with lead balance weights is prohibited.

Note:  EASA AD 2008-0156, dated 19 August 2008 refers.

Compliance:

1.    Initial inspection upon accumulation of 1800 flight hours TSN of blades, and thereafter inspect at 50 flight hour intervals.

This Amendment becomes effective on 2 September 2008.

Background:

In response to recent incidents, the manufacturer recommends an immediate inspection for bulging on the upper and lower surfaces of the main rotor blades in the area of the outboard lead balance weight.

Amendment 1 included all main rotor blades.

Amendment 2 reflected the changed issue date of the LBA AD, no further work was required.

Amendment 3 was issued in response to a revision of the related LBA AD.  The amendment corrected applicability and specified the requirements of the latest LBA AD.

Amendment 4 is issued to exclude certain Main Rotor Blade part numbers from inspection in accordance with this Airworthiness Directive.  There is no change to the requirements or compliance.

Amendment 5 is issued to advise that blades are now available that do not have lead balance weights and that fitment of these blades is terminating action for the requirements of this Airworthiness Directive.  The inspection requirements for those blades that have balance weights are retained.

David Villiers
Delegate of the Civil Aviation Safety Authority

22 August 2008