It's best to follow SOP. One very common error I used to see among less-experienced types was to extend flaps at or near Vfe. While this
does help in slowing down/getting down at higher flap settings, it is pretty much useless at the initial flap settings. (All you're really doing is beating up the flaps/slats....not really adding much drag.)
Those of us who fly (in my case, 'used to fly') the 320, know the SOP....speed brake is good down to/including FLAPS 1. "Not recommended" FLAPS 2 or more. Auto-retract with FLPAS FULL on the 319/320, FLAPS 3 on the 321.
Gear can, of course, be extended at 250 KIAS (below FL250
) but preferably at or below 220 KIAS to save gear door wear and tear...and to minimize soiled pants among passengers. Gear works good to add drag.
Once deployed, it's cumbersome to retract the gear.....once you've realized that you've thrown out the gear too early....now, you're having to add thrust earlier than you wanted. (
I've never made
that mistake!
)
(Joking, of course.)
Granted, the speed brakes work better at high speeds (duh!), but will also work (to a much lesser extent) at low speeds. Still better than working out flaps/slats at Vfe.
Used to fly with a captain on the 727 who refused to give me flaps until I was
exactly at the SOP flap speed schedule. He told me if I had planned my descent and approach better, I wouldn't have this problem.
While everyone hated to fly with this guy, he
did teach me to better plan my descents. (Actually, he was on hell of a pilot. I learned a lot from him.....once I got past the yelling, screaming, and smart-assed comments.)
So, again, it's best to follow the SOP. Believe it or not, the guys who write this stuff, generally know more about it than you do. (There are exceptions...but few.) SOP keeps you out of trouble. I've found the SOP, if valid, worked to my advantage.
"Sorry Captain XXXX (the chief pilot), but I was merely following the SOP." This doesn't give him much ammunition to shoot you with...does it?
Fly safe,
PantLoad