Why in the chicago 757 incident did the engines not shut down using the fire handles? In most aircraft pulling the handles will shut of fuel and hydraulics going to the engine, with a cable operated mechanism. How does this work on the 757?
All RB211 from the first -22B on the Tristar to the latest Trent have electrically operated HP and LP fuel shut off valves and spar valves. The spar valves are powered by the battery for safety, I suppose the case where the crew will knowingly deplete the battery, but still have main DC bus power was not envisaged in the design case.
The B777 even has special spar valve batteries to cater for this case, so perhaps they though of it?