Critical Engine
 

Can anybody help me with an explanation for the following please?

I have recently started to fly a new aircraft type, it's a light twin turboprop (high Wing) with a MTOW of 4,000kg. There is a high lift wing on the aircraft with a fixed undercarriage (apologies for being vague, but for the operators privacy I don't want to give the aircraft type away). Both props on the aircraft spin clockwise when looking at it from behind. VMCA for the aircraft is 60kts and rotation speed is approx 80kts. With regards to systems both engines supply one generator busbar, so with one engine shut down you will not lose any systems, you will just be limited by load.

Question: The AFM states that for takeoff, the critical engine is the right hand engine, but for the cruise the critical engine is the left hand engine. Obviously it makes sense that the critical engine is the left hand engine, but I just cant make sense of why it's the RH engine for take off. I have asked other colleagues about this and we can't come up with an explanation. Any idea's.

P factor on takeoff makes the left engine the critical engine because the right side of the engine prop has the highest AOA. That, of course is why you use right rudder on takeoff. Beats me.

Possibly a VMCG issue

Is this an Islander with Vmc below stall speed? That might be your answer.