Darkness night, engine failure soon after takeoff, heavy load, complacently not expecting, one mile from the airport speed still low probably, too much to keep it flying. All guesses but easy to visualize. Had it been daylight and he could have seen the terrain dropping away, he would have had some visual push over room to fly down in. Speculation of course. Too easy in a twin to let your mind wander for those first two or so critical minutes.