Although the final report has not been finalized yet, experienced Boeing pilots have independently determined that the accident of Asiana 214, B777 may have been caused because the pilots had a use misunderstanding of an autoflight mode called Flight Level Change – FLCH.
The experts, stated that entry into Flight Level Change (FLCH) during the approach would have caused the engines to remain at idle despite the pilots having set the autothrottles to maintain 137 kt., the target approach speed. One group of pilots has concluded this based on intimate knowledge of the 777-200ER’s automation systems; the other by flying scenarios in a 777 simulator.
Their analyses draw in large part on information presented in four NTSB briefings after the crash from pilot interviews and the cockpit voice and flight data recorders.
A case where a mix of automation and manual flight could have created an accident?
Boeing has always stated that the final authority on any of their aircrafts is the pilot, for that reason on any Boeing family airplane you can withdraw all the automation and fly it the way you fly a small Cessna.
Airbus is a completely different story, their automation philosophy is based on the premise that humans are prone to mistakes and for that reason in the lowest level of automation the final authority is always the on board computer.
The accident of Asiana B777 shows that pilots can make mistakes in the use of automation combined with manual flight and generate and accident with their actions.
But on the other hand, we have the accident of Air France 447 A330, that shows that when all automation was lost and the flight mode of the aircraft reverted to a mode called “alternate law” , the pilots were not able to recover the aircraft from a high altitude stall.
Complacency on automation related accidents, started to appear several years ago and still aviation industry has not find a way to match pilots and computers.