I am not suggesting that someone parachuted from the plane, only that I know it has been done before by DB Cooper. Actually , I don't really know that apart from media stories
Yes and DB Cooper exited from rear door of a 727, hence the photo illustrating that point earlier in this thread.
Just to finally nail this one on the head (hopefully) it's impossible to exit the side doors of a jet airliner due to the aircraft low wing design. Meaning if you tried to exit in front of the wing, you'll likely instantly hit the wing itself if you didn't pass through an engine. . Exiting from centre door would be impossible due to thrust from engines would rip you to pieces. Exit from rear door would not be possible due to close proximity of rear horizontal stabilisers.
You only have to study a picture of a B777 to see this. Even the most expert skydiver with specialised equipment would not attempt to exit a B777 even under optimal conditions.
The only jet airliner other than a 727 you could possible exit from, would be the British Aerospace 146 since that is a high wing design, you could exit the rear side doors, however doing so while engines operating would risk having yourself and your gear damaged if not destroyed completely from engine thrust on exit.
"The B777 is equipped with four Emergency Locator Transmitters (ELTs). These activate when the plane experiences an impact, contacts water or sinks to a depth of 3-4m. The pilot cant disable them and it is impossible to land on water without them activating?"
The pilot can't disable them in a airliner like the B777 as they are located in the tail of the aircraft. However you can test them manually from the cockpit to confirm they are working.
Airliners have ELT and ULB. ELT on aircraft are activated on land if they are not destroyed in the impact, they do not work underwater. Underwater Locator Beacon is in the blackbox and emits a signal as part of the black box ping.
ELT you are referring to which activate when make contact with water float and are mainly used in small aircraft/helicopters,yachts,ships,lifeboats etc
