Anent three-engine ferry flights I probably shouldn't tell this, but in the pre-certification days we'd come back from a demo and landed at Luton to clear customs, it being a Sunday. In those days there was a tendency for the quill shaft in the starter train to fracture and sure enough when we were ready to go only three of the four started. Captain Speaking turned to me "you've done the ferry calcs: are we o.k. to take off?" and as we were only going to Hatfield we were quite light so off we went.
Levelling out at a suitable FL for the ten mile trip, Co-pilot Watching said "we've got good N1 and oil pressure on that engine: let's see if it'll start." It did, of course, so we had all engines running for the approach and landing after a three-engined take-off!

Was sitting at the hold as a 4 engine TP trundled past and gracefully lifted itself into the air. As the nose gear left the ground the number 2 engine spun down in a weird sort of way. Engine failure reported and ATC told they were going on route and not returning.

Grey haired aviation god next to me in the LHS sighs and said.

"Good job they got off the ground before the starter motor burned out"