John, I beg to differ (slightly I think) – “STOL is a peculiarly military thing”.
IIRC ‘STOL’ was a special addendum to Canadian certification requirements (possibly FARs) and enabled DeH (Aaah) Canadian types to undertake unique operations, e.g. Dash 7 into Aspen and Vail.
The Canadian document (working paper 7… ??) was used as the basis for UK CAA certification of the BAe146 before the advent of JAR; which interestingly the 146/RJ did not meet due to the way in which the 2 deg margin was demonstrated vice tailwind and anti icing use.
My recollection of military STOL is associated with the Lysander, Shorts Pioneer(s), and then the Harrier; the first two types being more closely associated with ‘light’ civil ops. I exclude the rotary wing thingy’s.
rl82 Steep approaches also have a noise advantage; the BAe146 Flight Manual has a table relating approach noise and glideslope.