Bit of thread drift as not VC10 . Tridents 1/2/1e/3s , all could use reverse in the air . Memory say max 10,000 HP rpm on the outers , ie eng 1 and 3 . We used it regularly , though rev and or speedbrake in normal use was judged to be a poorly planned/executed approach .
Though if Wx , ATC , or fun dictated was a normal op. Have forgotten minimum ht. of cancelling rev.
Positioning an empty a/c with no.2 at idle , VMO of 365 , speedbrake [ airbrake ] out and 10,000 rev on outers . Descent rates of in excess of 17000 fpm were seen.
For precision landings , or short runways [ old EDI or ABZ , specially if ILS flown {only 1 ILS then } in a max tailwind ] , or fun [ practice really ] again.... Call from Handling Pilot to Non Handling Pilot [ throttle handler , as HP could not comfortably reach throttles and stick ] was '' Power Off , 10,000 Reverse '' , if judged correctly it cushioned the touchdown nicely , got retardation in early before brakes and airbrake were used .
Don't remember any restriction on a G/A from that position , and like an Autoland G/A , the runway may be touched in it's execution .
Only later on Boeings when reverse in , then No G/A to be carried out .
Yes the cabbage fields at ABZ and EDI were regularly visited , but not by those who pulled emergency reverse [ 12000 HP RPM ] early , and kept it in to a stop .
rgds condor.