There have been several high energy impact accidents where there was total destruction of the aircraft. Valujet 592, American Eagle 4184, USAir 427 and Eastern Airlines flight 980 that crashed at 21000 feet in the Andes Mountains (picture). Unlike some experts have stated that the crew would not have been aware of their proximity to the ground – that is not correct. In fact Enhanced Ground Proximity Warning System (EGPWS) uses a virtual terrain database to provide a crew with advanced warning of dangerous proximity to high terrain. The fact that there was no evidence of remedial action to level the aircraft or take action to avoid terrain will be a key issue.
The CVR maybe the more critical black box in this accident.
Assuming the normal flight control law was in effect and the descent was commanded via the autopilot, under normal circumstances would the latter take any action to adjust the programmed flight path if EGPWS detects an unsafe proximity to terrain while under autopilot control? Would the FMGEC be responsible for handling all of this? Or will the aircraft even in the Airbus fly-by-wire system just continue to execute a commanded descent by the pilots and reply on them to take appropriate action if this starts to bring the aircraft into danger?
Members may be aware that the Flight Data Recorders for EAL 980 are reported to have been recovered, 31 years after the disaster. https://operationthonapa.com/31-years-later-we-found-the-flight-recorders-786d0f9fde61#.dnzxsvot7
The F980 flight data recorders were not recovered. The searchers simply found some pieces of orange-painted metal that may have formed portions of the recorders’ casings.
Enhanced ground proximity warning systems did not come into existence until the mid to late 90s – the original generation Ground Prox system were very limited because they could only determine what was directly below the airplane – thus because mountainous terrain typically rise sharply in the path of the airplane many accidents occurred where the GPWS activated moments before impact or not at all in mountainous terrain. USAir 427 and American Eagle 4184 would not have benefited from EGPWS.