Originally Posted by
capngrog
Listening to the tower conversation with the B-17 (N90312CF), the pilot reported: " garbled ... number four engine. We'd like to return and blow it out". This sounds like there was a fire involved, but that should not have caused a control problem with the airplane unless the fire was well advanced. As to my speculation, well here goes. There may have been a massive oil leak in the No.4 engine resulting in rapid loss of engine oil pressure and ability to feather the propeller. The leaking oil may have caught fire. Inability to feather an outboard engine (in this case, no.4) would cause serious control problems. End of speculation.
Nine-O-Nine was a beautiful airplane, and its loss was a disaster. The loss of lives aboard was a tragedy. God bless.
Grog
Complete loss of oil would not be a problem due to a broken line or an engine problem as the oil tank has a stand pipe of a few gallons of oil which is only available to the feather motor for feathering. All aircraft with the big round engines have this safety feature incorporated into the design and we regiously check the feathering system before every flight.