Takeoff Attempt
The pilot initiated a takeoff without having completed performance calculations for the high density altitude conditions. After the aircraft lifted off initially, it failed to climb or accelerate. The pilot decided to continue the takeoff by lowering the nose, allowing the aircraft to settle back onto the runway, and then rotating a second time at a higher indicated airspeed.
Encounter with Downdrafts
During the climb-out following the second liftoff, the aircraft entered an area of downdrafts. The pilot became concerned about clearing tall trees along the takeoff path and elected to make a precautionary landing straight ahead.
Landing and Nose-Over
The pilot successfully touched down, but the aircraft landed in a wet, marshy, swampy area. When the nose wheel contacted the soft terrain, it sank in, and the aircraft nosed over.