I agree that the acting isn't exactly RSC territory but cut them some slack - these films are not cheap to make so my hunch is that the actors involved were people involved with aviation primarily and perhaps enjoy a spot of am-dram at weekends.
BTW, check this thread out:
http://www.pprune.org/forums/showthread.php?t=256248 
VFE.
PS: Loved the Oliver story: "enough mistakes to fill a sick bag!".