The FAA has issued an Emergency AD aimed at keeping A220 pilots from hitting the wrong button by forbidding them from hitting what they incorrectly think is the right button. The AD addresses an issue with the panel of the Bombardier-designed airliner that makes it possible to engage the autopilot when the intent is to engage the autothrottle. Transport Canada issued its own version of a similar AD earlier this month after hearing of 38 incidents in which crews have inadvertently hit the autopilot button while aiming for the autothrottle button. Two of those incidents were “nearly catastrophic” because they happened on the takeoff roll and the autopilot commanded the aircraft to pitch up before V1. That’s why the A220 aircraft flight manual (AFM) prohibits engaging the autopilot below 400 feet AGL.
But the AFM does not prohibit trying to re-engage the autothrottle (turbulence can knock it off), probably because the autothrottle won’t re-engage above 60 knots and below 400 feet. That apparently doesn’t stop pilots from trying. “In September, 2022, there was an incident in which the autothrottle disengaged during takeoff and when the flightcrew attempted to reengage the autothrottle they mistakenly engaged the autopilot which resulted in the aircraft rotating below the V1 speed,” the AD says. “This resulted in a low energy takeoff which is extremely hazardous as it could lead to the airplane stalling and/or impacting terrain.” The AD attempts to address that kind of confusion by adding a note to the AFM “prohibiting selecting or reselecting autothrottle after the thrust levers are advanced to the takeoff setting until the aircraft is at or above 400 feet above ground level.”