ST,
Apparently there were two Chinooks based at Aldergrove on a staggered 6 week rotation. The ZD576 was the first Mk2 to be based in NI and it was flown in on May 31 two days before the crash. I've been told that the 1991-1994 tasking records were destroyed about three weeks before Christmas 2000 which funnily enough more or less coincides with my report of the Portrush Chinook on PPrune.
Mrs Bellchambers in a letter dated 19 September 2002 claimed that one of the two Mk1s based at Aldergrove was returned to RAF Odiham on May 31. She also reported that the remaining Mk1 was 'not in service on 2 June 1994'. The ZD576, a Mk2 with single-tone dark green camouflage, was definitely not the Chinook seen near Portrush. 'There were no Mk1 Chinooks (which have a "patchwork camouflage") or any other RAF Chinooks flying in Northern Ireland on 2 June'.
If the Portrush Chinook with its military camouflage wasn't an RAF Chinook who might it have belonged to? Why wasn't the remaining Mk1 at Aldergrove used?