As soon as I close the cabin doors, you can hear the low throbbing sound I'm trying to describe. It sounds like an old steam engine. Nothing is running, I haven't even flipped a switch. Same thing on the second chopper. Dead silent at Krasnodar, but I demonstrate a failed cold weather startup. This is unedited for speed purposes and when I look over my left shoulder, that's me looking at the second monitor and confirming acdelta's startup procedure. What did I do wrong? I hit the battery switch and immediately hit the starter.