When conﬁguring, VLS is more critical than VFE, which
in turn is more critical than manoeuvring speeds (S and F
speeds). Both VLS and VFE are trustworthy with jammed
When conﬁguring on approach, ﬂaps do not begin to extend
until conf 2 is selected.
Slat position does not change between conf 2 and conf 3.
Dual hydraulic failure fundamentals:
You will always need to gravity extend the gear, so you
will never be able to retract it on the go-around.
If you only have blue, you lose the ﬂaps; if you
only have yellow, you lose the slats. The ﬂaps/slats
jammed procedure (including go-around modiﬁcations)
is therefore incorporated into both these procedures.
If you only have blue or yellow, it will be a Direct Law
landing; Normal Law is retained if green is available.
Direct law is triggered by gear extension. If you only
have blue, the ths is frozen, so you need to trigger Direct
Law late (at conf 3, VAPP) to get neutral trimming
of the elevators. If you only have yellow, the aircraft
handling is sluggish; trigger Direct Law early (at 200kt)
to improve responsiveness.
You’re going to need a longish runway. Worst case is if
you only have blue, since you have, at best, accumulator
braking and you’re coming in fast due to lack of ﬂaps.
Yellow is better since you have alternate braking, and
its mainly about the lack of slats. If you have green, its
not really all that bad.