Boeing Fuel Dump and Off-sets.

[brown_eyes]

I wonder if the Boeing pilots can assist me? I have 2 questions:

• Why can’t you dump fuel with flap extended?
• When wanting to divert say 10 miles right of track, I am told you cannot access the off-set prompt on the RTE page shortly after take-off say 5000 ft but only in the latter part of the climb.

Could somebody please tell me under what conditions the off-set prompt becomes visible on the climb.