Hello,
I couldn`t find the answer to this question in our OM, in Bill Bulfer`s bibel nor in the FAQ section of PPRUNE.
Here it goes:
B hydraulic system operational but we perform an alternate flap extension (for example due to a trailing edge flap disagree). Afterwards we retract the flaps withe the alternate system. That means: Trailing edge flaps up, leading edge devices fully extended. Right? But now we place the alternate flaps master switch back to normal... I guess the leading edge devices retract now. Or am I wrong???
But Boeing states in its Trailing edge flap disagree NNC : "...the drag penalty with the leading edge devices extended may make it impossible to reach an alternate field"
Best regards