Cornish Jack:-
the origin of 'hicopleters' for helicopters was ... Handling Squadron at Boscombe Down. Their AL (10, I think) for the Whirlwind 10 was quickly followed by an AL11, which was almost entirely composed of " for hicopleter read helicopter" 
I don't know when AL11 for the Whirlwind 10 was, but my AP129 Vol1 Pt1 Sect1 Ch16 (Basic Helicopter Aerodynamics) was amended by AL8 April '59 in exactly the same way. Chicken or egg?