ATR 42
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed
Environment - Non Weather Related; Human Factors
We were preparing to start engine 2 in Hotel mode. At the time; the plane was at the parking spot in [airport] with the passenger board ramp attached and the Engine 1 prop strap installed. I was conducting IOE from the right seat; and we had reached 'Start Selector' on the hotel mode checklist. I briefly looked right to clear engine 2; and the trainee Captain had selected Start B on the overhead panel. I didn't see it happen; but somehow the starter for Engine 1 was engaged. I heard the starter running and looked up; noticed the starter on engine one; and immediately selected 'Off/Start Abort' to kill the starter. I think the starter was engaged for only a couple of seconds; and Nh on engine 1 never went above 9% or so. Fuel was never introduced to the engine. Following the event; I debriefed both the trainee Captain and the ground crew. Evidently when the starter was running one of the rampers was near the engine and was rushing to remove the prop strap. I advised the ramper that next time he should clear the engine area instead of rushing to remove the strap.I'm really not sure how the starter was engaged; as I didn't see it happen. As best I can tell it was purely an accident; i.e. the starter button was accidentally bumped.
ATR 42 Check Airman reported that examinee engaged the starter on the incorrect engine during engine start sequence.