A purge button cap has been implemented as a result of recent damage to PSTASS units whilst in transit.
Recent incidents involving PSTASS have identified cause of failures to be attributable to accumulated damage (reference previous alert 'Damage to PSTASS Assemblies' Nov 16). A comprehensive parts replacement program was completed, including new valve bodies. Since introduction of replacement valves, there have been occasions when the PSTASS assembly has been turned on after transportation and the air contents has depleted until the ratchet knob has been cycled through the on/off function. The root cause is yet to be determined by the OEM and in the interim it is necessary to ensure the unit remains in the live mode (air turned on) in the transportation bag and a protective purge button cover fitted to eliminate the risk of accidental loss of air contents
WARNING: Failure to handle PSTASS with care may result in damage to assembly
Lifejackets & PSTASS only to be transported in the live mode with PSTASS ratchet knob in the ON position
Lifejackets & PSTASS to be transported in transport bags with the purge button cover fitted to the second stage mouthpiece
Purge button cover fitting/removal only to be carried out in Heli-Admin area and not on helidecks or stairways
Nothing should be placed on top of the transportation bags whilst in the aircraft hold or whilst being transferred by ground handling support.
All PSTASS offshore handling to be in accordance with the QF 27 Offshore Handling of MK50 lifejacket & PSTASS (EBS) rev 4 - procedure.
Any failures of PSTASS to be reported to heliport staff