Caravan 208B
Flight Crew Commercial; Flight Crew Instrument
Distraction; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Other / Unknown
Flight Crew Rejected Takeoff
Human Factors
Outlet circuit breakers tripped overnight so the planes battery and engine was cold. I placed the heater duct under the RH cowling of the aircraft into the engine compartment to warm it up and left the engine cover over it to keep the heat in. Prior to departure; I decided that I was going to need an assisted start regardless so I moved the heater from the engine to the copilot door to heat the cabin (this is where I believe the latches were initially left unlatched). I left the engine cover on not noticing the latches and walked away. Prior to departure; I removed the engine cover from the pilot side and removed the tail stand and chocks and started up. There was no sign of anything wrong until I was on takeoff roll and the cowling caught wind and came up into my view. I immediately aborted the takeoff roll and taxi back to parking. I normally check the cowling during my preflight and ensure it is latched; but the heater event happened after I completed my preflight inspection. I think that many factors contributed; but the main reason for me was that I had never done what I did with the heater like that before so my preflight routine was off. I also failed to notice the latches on my walk around because the engine cover was on while I was on that side of the plane; which I normally take it off before I even go inside to get my final manifest. I will make sure that I stick to my routine when it comes to the pre-startup walk around and be very vigilant and aware when something non-routine happens. Having this event permanently in my brain will also help me never do this again.
Caravan pilot reported rejecting a takeoff due to a partially separated cowling.