Airships were traditionally lighter than air which meant you had to permanently lasso them down with an army. Airlander can effectively make itself heavier than air, hence minimal groundcrew requirement and a more rugged proposition out in the wilds.
It can hover at 0kts without stalling - there are pictures of it floating in the hangar for testing prior to opening of the doors.
It makes a rolling takeoff V1/VR 30kts:
Pilot published this big feature recently
http://www.pilotweb.aero/features/the_airship_redrawn_will_this_revolutionise_air_travel_1_463 4083
How it takes off with an extra 10T payload I don't know. You don't use the ballonets for this to suddenly make it less dense, only for trimming and controlling the internal pressure of the envelope.
We're all scratching heads a little over this. To be fair they've had decades to understand the theory and we're all playing catch up.
An earlier question related to the bow thruster above the nose, this is on the Airlander 50 CGI image but not on the 10.
The unusual attitude that was adopted prior to the incident was deliberate. I'm told by airship guys that they do this to punch through an inversion, which can critically affect the buoyancy. I wasn't there but did they go around off the first attempt & tried this second time round? Or maybe it was on the test flight plan.
The speed was low but there just wasn't a flare, only HAV will know why.
Fingers crossed to see it back up there this winter.