ACHER QUALITY ASSURANCE
ATTN: ALL AIR CREW.
On two occasions the helicopter pilot service helicopter has suffered minor compressor damage to the starboard engine. It has been assumed that this damage has occurred as a result of landing at unprepared sites such as various wharfs to drop or recover marine pilots. Various measures have been implemented to prevent similar damage.
THESE MEASURES WILL REMAIN IN PLACE.
On both occasions the damage that has occurred has not been consistent with solid object damage. Damage has occurred only to the first stage compressor and then the object has apparently passed through the engine without causing further damage. The damage has been consistent with something ‘soft’ impacting the first stage compressor. No sharp edges or cutting that would normally be associated with a nut, bolt, stone or some other solid object being drawn through the engine.
It is known that some maritime vessels burn very heavy crude oil. This oil is routed via pre heaters before being burnt to produce the energy required for steam boilers. It is also known that some comparatively large burnt carbon deposits are expelled through the funnel exhaust system.
A possibility exists that if the helicopter is flown through funnel emissions or near to the funnel in the hover, these deposits may enter the engine. An approach to a vessel into wind, Starboard to, is consistent with the Starboard engine only, being affected.
ALL CREWS TO AVOID FLYING THROUGH, OR HOISTING TOO CLOSE TO FUNNEL EMISSIONS