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 5 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 6
Main Rotor Blade
12/2009
 
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 4 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 4 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 or Revision 3, 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 4.
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 4 or later revision, before further flight replace each affected blade with a serviceable blade.
Replacement of MR blades does not constitute terminating action for the repetitive inspection requirements of this AD, except when all MR blades installed on a helicopter are MR blades that have a P/N not listed in ECD
ASB-MBB-BK117-10-108.  In that case, this AD no longer applies to that helicopter.
Note:  EASA AD 2009-0199, dated 08 September 2009 refers.

Compliance:
1.    a.     For MR Blades with less than 1800 FH time since new:
Within 300 FH after the effective date of this AD but not later than upon the accumulation of 1800 FH of the MR blade, whichever occurs first.  Inspect thereafter at intervals not to exceed 300 FH.

 
 
 
b.    For MR Blades with more than 1800 FH time since new:
Within 300 FH after the effective date of this AD, or within 300 FH since the last required inspection. Inspect thereafter at intervals not to exceed 300 FH.

 
This Amendment becomes effective on 19 November 2009.

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 was issued to exclude certain Main Rotor Blade part numbers from inspection in accordance with this Airworthiness Directive.  There was no change to the requirements or compliance.
Amendment 5 was 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 were retained.
This Amendment extends the repetitive inspection interval from 50 to 300 Flight Hours and depending on inspection findings requires replacement of MR blades.  Additionally the prohibition of reinstallation of MR blades with lead balance weights (having a P/N not listed in ECD ASB-MBB-BK117-10-108) has been deleted.

David Villiers
Delegate of the Civil Aviation Safety Authority
28 September 2009