AD/EC 135/22 External Mounted Hoist System (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 EC 135 Series Helicopters

AD/EC 135/22 External Mounted Hoist System 6/2009 TX

Applicability:

Models EC135 P1(CDS), EC135 P1(CPDS), EC135 P2(CPDS), EC 135 P2+,
EC 135 T1(CDS), EC 135 T1(CPDS), EC 135 T2(CPDS), EC 135 T2+,
EC 635 T1 (CPDS), EC 635 P2+ and EC 635 T2+ helicopters, all serial numbers; if equipped with a Goodrich external mounted hoist system with boom support part number 44301-500, 44307-500 or 44307-500-1.

Requirement:

1.    Inform the flight crew of the instructions contained in Eurocopter Deutschland Alert Service Bulletin (ASB) EC135-85A-036 original issue, or later EASA approved revision.

2.    Accomplish the visual check of the boom support in accordance with the instructions of ASB EC135-85A-036 original issue, or later EASA approved revision.

3.    Accomplish the visual check of the boom support in accordance with the instructions of ASB EC135-85A-036 original issue, or later EASA approved revision.

4.    If, during any check required by Requirement 2 or 3 of this Directive, cracks are detected within the boom support as specified in the Requirement document, remove the affected boom support or replace it with a serviceable part.

From the effective date of this Directive, installation of a boom support part number 44301-500, 44307-500 or 44307-500-1 is not permitted on any helicopter unless it has been checked in accordance with the instructions of ASB EC135-85A-036 original issue, or later EASA approved revision.

Replacement of the boom support does not constitute terminating action for the repetitive inspection requirements of this Directive.

Note:  EASA Emergency AD 2009-0093-E refers.

Compliance:

1.    Before further flight after 21 April 2009.

2.    Before further flight after 21 April 2009, and thereafter before each first flight of a day.

3.    Before each first external mounted hoist operation of a day.

4.    Before further flight.

This Airworthiness Directive becomes effective on 21 April 2009.

Background:

During a recent pre-flight check of the external mounted hoist on a Model
MBB-BK 117 C-2 helicopter, cracks were detected on the boom support part number 44307-500.  This condition, if not detected and corrected, would impair the structural strength of the boom, potentially leading to failure of the boom support.  This could result in loss of the boom and attached loads, endangering helicopter operation and possibly causing injuries to persons on the ground.

David Villiers
Delegate of the Civil Aviation Safety Authority

20 April 2009