Hi again!
Hmm, I've been fishing around some more and this is one reason I've found for Boeing recommending against using VNAV prior to flaps retraction. (Haven't got a clue if it's correct though
)
"However, note that on the 737, VNAV engagement before flap retraction is highly discouraged since the FCC does not have any knowledge of the position of leading edge devices. (placard
limiting only looks at the trailing edge flaps) Thus if a leading edge device fails to retract, there is nothing in any of the systems to prevent overspeeding the leading edge device. Once flaps are up and the crew has verified that the LE extended and transit
lights are extinguished, then it is OK to engage VNAV."
Does all the other Boeings and 'buses have more "control" over what's going on with the leading edge devices then? Or is the risk of overspeeding the leading edge device just deemed so unlikely that it's nothing to bother about?
This has gotten me more and more curious!
rgrds
/fredrik