On September 8th, 2015, a pilot left Point Cook Airfield in the Australian State of Victoria for a solo navigational training flight.
She didn’t make it back: the plane “impacted rising terrain” about two-thirds of the way into the journey and the Australian Transport Safety Bureau report on the accident, published today, offers some interesting observations about the limitations of automation and when to rely on it.
The Bureau’s investigation into the incident found that the human pilot had engaged autopilot but then tried to use manual controls.
“It is likely that the pilot manually manipulated the controls while the autopilot was on and engaged in a vertical mode,” the report states. “As a consequence, the autopilot re-trimmed the aircraft against pilot inputs, inducing a nose-down mistrim situation, which led to a rapid descent.”
The autopilot was also used below the minimum height required by the flight training organisation, which meant the pilot didn’t have enough time to avoid the accident.
Another big contribution to the crash was that “There was no advice, limitation, or warning in the aircraft pilot operating handbook or avionics manual to indicate that if a force is applied to control column while the autopilot is engaged, that the aircraft’s autopilot system will trim against the control column force, and possibly lead to a significant out of trim situation.”
The report also noted the pilot was not required to receive training on the autopilot’s functions and that the flight training school has since updated its manuals to explain the limitations of automation.
But the report also concluded that “Fundamentally, pilots should be aware that if the automation is not performing as expected, then the safest option under most circumstances is to disengage the system and manually fly the aircraft.”
As more of us clamber into cars with self-driving capabilities, that advice may become words to live by. ®