Maintenance and repair involving the removal and refit of the
variable stator vane levelling arm pins to the Pratt & Whitney
PW4000 engine. This procedure involves the flaring of the pins for
retaining in the synchronising ring backed up by a service bulletin
edict to tack weld the pins to the ring. These procedures appear
not to be successful in accomplishing the desired retention of the
pins.
Refer to ASOR BO/200400726 for details.
Safety Recommendation
The Australian Transport Safety Bureau recommends that the Civil
Aviation Authority of Singapore liaises with Pratt & Witney's
Singapore based overhaul joint venture to review the process for
accomplishing the ring pin flaring and compliance with the service
bulletin PW4ENG72432 to ensure the processes are appropriate and in
accordance with the service bulletin.
