Crew experience? Composition
Were they both captains on such an VIP flight.?
Experienced, but not lately? and NOT from right hand seat?
Anyway, never seen anyone ever do the flaps before gear, but this fits the profile perfect as we know it.
How:, Cpt in f/o seat , not instructor or used to fly from that side.
Nearest Flaps
Far lever, Gear,
ooops.
Gear and Flaps retracted in wrong sequence, not flyable, end story.
Unlikely, but simple,
And with a normal gear flaps sequence they would hit 2 miles and not 1 mile after liftoff if somthing else happened just at flaps up.
Hit me ,
May their music live on.
Cpt B