AD/S-PUMA/85 Main Rotor Drive Epicyclic Reduction Gear Module (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 AS 332 (Super Puma) Series Helicopters

AD/S-PUMA/85 Main Rotor Drive - Epicyclic
Reduction Gear Module 6/2009 TX

Applicability:

AS 332 L2 model helicopters.

Requirement:

Unless already accomplished per the requirements of AD/S-PUMA/84 (EASA Emergency AD 2009-0087-E), remove and inspect the Main Gear Box (MGB) epicyclic reduction gear module in accordance with the instructions of paragraph 2.B.2 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.81 initial issue dated
10 April 2009 or later revision approved by the European Aviation Safety Agency (EASA).

Note 1:  Accomplishment of actions required by this Directive does not terminate the repetitive inspection requirements as defined in AD/S-PUMA/84.

Note 2:  EASA Emergency AD 2009-0095-E dated 17 April 2009 refers.

Compliance:

Before the next flight after the effective date of this Directive

This Airworthiness Directive becomes effective on 20 April 2009.

Background:

This Telex Airworthiness Directive is issued following the accident of the AS 332 L2 helicopter registered G-REDL that occurred on 1 April 2009, off the coast of Scotland near Aberdeen.

Early investigations showed that a failure within the epicyclic reduction module of the MGB resulted in the rupture of the MGB case, which allowed the main rotor head to separate from the helicopter.  In the light of this information, enhancement of the means for detection of MGB contamination was deemed of the utmost importance.  As an initial precautionary measure Telex AD/S-PUMA/84 was issued with that aim.

Today, the investigation is still in progress and examinations of the remains of the MGB epicyclic module, and associated areas of the helicopter, continue apace with the aim of establishing as soon as possible the sequence of the failure and initiating cause.

In order to complement measures mandated by AD/S-PUMA/84, this new Directive is issued to require a one-time inspection for absence of particles in the MGB epicyclic reduction gear module on the entire fleet.

David Villiers
Delegate of the Civil Aviation Safety Authority

20 April 2009