A major contribution to upset incidents is the surprising onset of the event. Simulators can provide valuable training that improves crew situation awareness that may mitigate surprise or even a loss of control. This is also the time and place to control any adverse behaviours for acting without assessment, rush, or carefree responses. However simulators have many limitations when attempting to simulate the motions and sensations of an upset. They will not for example simulate the false climb illusion or anything similar that may be encountered during an upset or the recovery.
There are few really gross upsets; one that can be simulated and opens many eyes is fuel imbalance. With the autopilot engaged in level flight, and unbeknown to the crew, set the maximum lateral fuel imbalance before any alert is given. Disengage the autopilot – the surprise; and then assess how the crew use the cues of motion, instruments, and control feel to complete their recovery – if at all. The lesson to be learned is that the aircraft may not be in trim (zero force may not equal stick centre) and that the instruments are the most important cue.
For those doubters who say that this scenario will never be encountered, ask the UK 737 operator who had just such an event – at least 120 deg roll. Also, with some speculation, did a lateral force imbalance contribute to the recent Middle East 737 accident due to a possible slat asymmetry?
Thus the most important cues for upset recovery are obtained from the instruments, always believe the instruments; this too is the defence against spatial disorientation. Aerobatic training in aircraft or the simulator may give personal confidence in the aircraft’s capabilities, but it does not provide upset recovery training. This is achieved by dedicated instruction and practice of how to recover from unusual attitudes by use of instruments, first to asses the aircraft’s position, motion, and trends; then with rules and guidelines, safely recover to controlled flight as quickly and as safely as possible.