I was reading 'Operation Manna/Chowhound', a fascinating book about the Allied supplies of food to Holland in 1945. The author quotes the following account from a 550 Squadron report.
At 18:00, thirty aircraft and crew under command of Wing Commander McWatters took off for a Manna mission. The Lancaster returned to England after a successful drop. ...] Flying Officer Handley of BQ_K2 saw an American plane had come down in the North Sea and was almost submerged. The pilot immediately switched his FI to “emergency” (Identification Friend or Foe — a transmitter/receiver with which Allied planes could identify one another to themselves and to their air defence systems). When it descended to 60 m, the x crew spotted an American-type rescue raft with a possible occupant. After circling, the crew saw the raft was floating upside down and that it was empty. A ship was seen steaming south about 10 miles from the wreckage. The Lancaster flew towards it, circled the ship and signalled “sos Follow me”. The ship’s crew answered from the bridge, turned and followed 1(2 to where the e-17 lay half in the water. In the meantime, the Lancaster’s wire less operator had transmitted its position, altitude, etc and had received instructions to remain in the area. When the first ship to be alerted arrived at the scene of the wreckage, her crew launched a rescue boat to search for survivors. About 4 km from the site, the K crew spotted someone floating in the water, still surrounded by a parachute. There was no sign of a life jacket so the tail gunner threw one down into the sea, near the flyer, who was able to pull it on. A flare was also dropped to mark the spot. American Flying For tresses had arrived in the meantime so that the sky was full of airplanes. Two more survivors were spotted east of the wreckage. More lifejackets and flares were thrown into the sea. Sometime later, a Catalina amphibian plane landed on the surface and took aboard the first survivor. A Walrus amphibian also arrived and picked up a second man. While the Lancaster continued to circle, her crew spotted an empty life raft, and launched yet another flare and more life jackets. Almost immediately a third survivor was seen in the water. The 1(2’5 crew alerted the Catalina by radio and dropped flares to guide it to the spot, where the amphibian plane soon arrived to pick up the flyer. After a thorough search of the area, no more survivors were found and the Lancaster returned home to base.’