At one time it was a fairly common occurrence for 747s to shed flaps.BA had a mid flap fall off a 747 on the approach at Prestwick while training -the story I heard was it landed in the sea close to a couple of anglers in a dingy who promptly hitched a rope to it and towed it ashore.They then returned it to the training base at the Orangefield - presumably on their dingy trailer. Perhaps someone with first hand knowledge of the incident could confirm or deny the story - I heard it second hand.