A design flaw could cause a major problem for the Airbus A220 during takeoff, potentially causing an accident. The problem was reported by aviation authorities in the United States and Canada.
The problem was revealed by the Federal Aviation Administration (FAA) and Transport Canada, respectively the US and Canadian civil aviation authorities, after more than 38 occurrences of autopilot activation during takeoff. According to FlightGlobal, the problem would be during the activation of the autopilot on takeoff.
As a rule, the system is not activated until the aircraft leaves the ground and exceeds a minimum safe altitude. Activation before this can cause the aircraft to leave the ground prematurely, before the ideal speed, causing the aircraft to take off without enough energy for a safe climb, which may result in a fall due to lack of lift.
This trigger, however, has not been intentional, but caused by another problem: the automatic power control shutdown, the autothrottle🇧🇷
Automatic power control is used so that the aircraft’s configured maximum power is applied during takeoff and is not reduced. However, on the A220 this function is automatically deactivated if there is any “turbulence” caused by irregularities on the runway and also by divergence of speed information captured by different sensors (in case of failure).
If that happens, when trying to turn on this automatic power control, the pilots may end up pressing the autopilot button, which is exactly on top of the autothrottle and they are very close to each other, practically glued together.
This usability issue caused the series of occurrences. Therefore, Canada asked that pilots be educated about this problem, while the Americans want a rule be established so as not to reconnect the autothrottle during takeoff, followed by the manual use of power in any situation, as an additional layer of security to avoid unintentional activation of the autopilot.