Thanks for the concise summary. You should refer other late-entries to that post of yours
Once the rotor stalled the air resistance would slow rotor rotation to effectively zero in less than ten seconds.
Wow, that's really fast! My PPL autorotations had the throttle rolled off (to ~2000rpm) and I'd put pitch down + cyclic way back to prevent nose dive and then get back on pitch a little or otherwise RRPMs would skyrocket. Next check flight I ask and wait a bit with the pitch to see the initial RRPM decay..
The free fall time from 1000 feet is less than 10 seconds, however the aerodynamic resistance of the falling helicopter would probably slow the descent rate to around 20 seconds to impact the ground from 1000 feet. Hence the single return from the aircraft on ground radar showing a height of 400 feet after consistently being tracked at 1000 feet, i.e. it was pinged by radar mid fall.
So it was by no means a landing but a crash onto a rel. sturdy roof.
The prime switches were switched on (possibly mistaken fro the fuel transfer switches). When the engines failed due to fuel starvation, they ran down immediately and without warning due to the prime pumps operating to remove any entrapped air in the fuel being supplied to the engines. The rotor speed decayed significantly faster than in simulated or practise autorotations.
Wouldn't that be a very scary sound, two engine going slient? That would override any lights for me. Would
"3 seconds till pitch full down at hard engine out" be too slow an reaction in an EC135?
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the battery may not have been capable of carrying the system load so effectively all the lights went out in the cockpit.
Jeez, not even half a minute? Scary
