You are not describing the details we need. Please go offline, pick a plane, roll film, spawn on the runway, and show us the problem. Stop the film, go and then ZIP the film, and once others can see it they can reply "Oh, you're too slow" or "Oh, you've got your gear and flaps down" or "Oh, 3 of your 4 engines were idling, throwing you into a spin from the 4th engine" (or whatever the case may be.