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 Pratt
& Whitney plc review the processes used by its Singapore based
overhaul joint venture to accomplish VSV ring pin flaring and
compliance with service bulletin PW4ENG 72-432, to ensure the
processes are appropriate and in accordance with the service
bulletin.
