posted on Nov, 6 2019 @ 06:14 PM
In February of 2018, a SmartLynx A320 was damaged beyond repair during touch and go training. There were four student pilots, an instructor, a safety
pilot, and a civilian evaluator on board. Investigators found that a combination of factors caused the accident.
The fourth student was in the First Officer's seat when the aircraft lost elevator control. During the landing, the instructor was holding the manual
trim wheel, keeping the horizontal stabilizer from going to neutral. There was a slight rebound on the landing, leading to a logic discrepancy in the
elevator computers. One was in flight law, the other switched to ground law.
In addition, the computer recognized the manual trim being held as a runaway stabilizer. The override mechanism was supposed to activate three
microswitches, while disengaging the pitch trim actuator. The mechanism had been serviced with the wrong oil, causing the switches to not activate
Airbus is developing a fix that includes making the elevator computer more robust, as well as mitigating the effects of the computer not recognizing a
manual takeover of the trim wheel.