Document ID: chunk:federal_register_of_legislation:F2008L00387:body:0:p2
Version: federal_register_of_legislation:F2008L00387
Segment Type: other
Provision Reference: 
Character Range: 3798–5933

M1688                 332A32-3011-03M / M2016
             M974

                4. Do not install MGB main reduction gear modules fitted with freewheel shafts as listed in the applicability section of this AD on a helicopter, without having ensured that the freewheel shafts of the main reduction gear module has been inspected by an approved repair station.

             Note:  EASA Emergency Airworthiness Directive No 2007-0312-E dated
             21 December 2007 refers.
Compliance:     1. a) and b) Before further flight, after the effective date of this AD.

                2. Within 40 Flight Hours (FH) after the effective date of this AD and at the latest by 31 May 2008.

                3. Within 200 Flight Hours (FH) after the effective date of this AD and at the latest by 30 June 2008.

                4. After the effective date of this AD
             This Airworthiness Directive becomes effective on 13 March 2008.
Background:  This AD is issued following a hard landing which occurred recently while conducting in-flight OEI/engine failure training.  During a RH single-engine approach with idle rating training mode activated on the LH engine, the flight crew encountered a sudden loss of drive on the RH side of the MGB.

   MGB examinations revealed the failure of the RH freewheel due to excessive wear on some of its components.  In case of freewheel malfunction on one of the two MGB inputs, the resulting overtorque at the remaining MGB input, given OEI mode activation, may not be transmitted by the second freewheel if the latter too is severely worn.

   The analysis of the various recordings made during overhauls and supplied by various repair stations identified a list of offending MGB main reduction gear modules and freewheel shafts that are currently in service.

   Consequently, this AD prohibits OEI/engine failure training with rotorcraft on which MGB main reduction gear modules equipped with freewheel shafts as listed in the "Applicability" section above and mandates their replacement.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

14 January 2008