Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Confusion; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Aircraft; Human Factors
We were cleared for takeoff on [Runway] XXL in ZZZ. As pilot flying; I advanced the throttles to 40% and heard the Captain call 'stable.' I started hunting for the TO/GA button and was sure I found it. The autothrottle arm switch disengaged. The Captain reengaged the switch twice. It disengaged twice as I tried commanding takeoff power. We canceled takeoff clearance; taxied clear and called maintenance which resulted in an MEL for autothrottles. After all paperwork and communication was complete; the departure was normal. Once we were at altitude on the transit; I started thinking through the scenario in greater detail and realized that I may have pressed the autothrottle disengage button rather than the TO/GA button.This flight was my first at the controls in almost two months. I have less than a year of experience on the plane. I reviewed many things prior to my first day back; but TO/GA switch selection was one that I didn't specifically think about and it caught me off guard with less than ideal muscle memory.
FO was pilot flying. On takeoff autothrottles did not advance thrust levers when TOGA was pushed and A/T ARM switch clicked to the off position. I reset the A/T switch twice. Again the switch clicked to the down position. We then taxied clear of the runway and contacted maintenance to MEL the A/T system.At cruise the FO realized that he probably had been pushing the A/T disengage button instead of the TOGA buttons.
Air carrier flight crew reported the FO may have pressed the autothrottle disengage button rather than the TO/GA button during takeoff roll. The flight crew rejected the takeoff and cited the FO's lack of flying as a contributing factor.