Phil nobody knows at the moment what caused the crash.
The aircraft is fitted with a camera which should provide some evidence
We test all the time with simulated hydraulic failure approaches but if someone puts in a large input close to the ground it is almost irrecoverable due to the fact that if you put the hydraulics back on they kick violently making the situation worse.
Yes in theory one could fly into a confined area but you are really asking for trouble if it all goes pear shaped
I would personally advice extreme caution to all instructors and examiners whilst simulating hydraulic failure practice and at all times adhering to the OEB and OSD reports
Leon