3 eng ferry
My old outfit had detailed procedures for 3 eng ferry on the 747. Senior Check Capt LHS, Training Capt RHS, and Check Engineer (on the Classic). All to have done a training programme for this, with the whole crew to do a Sim refresher immediately before departing for the recovery. Gives you an idea of how it was viewed as a procedure of last resort.
This was also demonstrated by an Asian carrier in Manila. A construction truck gets stuck in the mud, 747-200 taxying in clobbers it with an engine. Management pilot nips down to recover it, and it didn't work bigtime. When I saw it a couple of days later they had managed to clear it off the side of the runway, but the nosewheel was sticking out from the side of the E & E bay and the remainder was also a mess.....I believe it was written off later. The airline in question later applied for a ferry out of Hong Kong, but were unable to supply the CAD with details of their training programme or qualified pilots, so no go.
Also know someone who watched a well-known cowboy in Scotland many years ago try to recover a Twin Commanche from an island strip with one inop. He also ended up in the weeds with a write-off!
To be approached with Major Caution I think