Originally Posted by
deltahotel
Alex. The min manoeuvring speeds for various flap settings are based on Vref. So min clean in Vref+80, min speed Flap 1 is +60, F5 is +40. etc.
DH, very nearly correct but I'd like to correct some of your terminology. The speeds you mention that are referenced to Vref are the
FLAP maneuvering (US spelling) speeds, not the minimum maneuvering speeds which are generally about 20kt+ lower than the equivalent FLAP maneuvering speed.
The minimum maneuvering speed for the current flap setting is shown on the PFD speed tape as the top of the top of the amber band and the flap maneuvering speed is shown as the number of the current flap setting e.g. for Flap 5, a green number 5 on the speed tape. Source: 777 FCOM 10-10 > Controls and indications > Primary Flight Display (PFD) > PFD indications
The Vref +20, 40, 60 & 80 speeds are the FLAP maneuvering speeds for F20, F5, F1 and Flap UP respectively and are the speeds we would normally fly as a minimum with those flaps settings but they aren't the minimum maneuvering speeds, which are always lower. Confusing isn't it?
Finally Vref+80 is normally referred to as 'minimum clean speed' but, as above it isn't the minimum maneuvering speed clean.
it's a bit like explaining the laws of cricket.