[twoparachute45]

Regarding your edit: that's a good point, but the vertical ascent rate of the chopper at those first few data points shows 400-800 feet per minute, which is consistent with a chopper taking off...'

edit: your second edit makes me think you're right though, tonight's flight track was pretty consistent with the past flight track where it looks like it both took off from and landed at Fort Belvoir.