Alboule wrote:
It is what AC27.143 defines as an acceptable means of compliance to Part27.143:
“whichever is greater”…..
I have many times been told by heli pilots that a Robinson gives you 0.7 secs to react to an engine failure.
Now, total sudden failures with 100% loss of power, like a crankshaft snapping, are very rare, which may be how that heli gets away with it.
The 1 second thing applies to R22 only, not R44 or 66.
Also, it’s 1 second to start moving the collective down. You don’t have to be in an autorotation one second after power loss.
Peter wrote:
Now, total sudden failures with 100% loss of power, like a crankshaft snapping, are very rare, which may be how that heli gets away with it.
Maybe that makes it worse. If you hear a loud bang also in a plan you push the nose down. But if the fault is not so obvious you check the instruments etc. observe the situation. I had this happen and I was getting dangerously slow before I realized I had to push the nose down. This was also because all my training back then did only focus on violent immediate full loss of power.
Good point…let me think…what happens in your typical SEP on a Vy climb out after take-off if you lose all engine power and then take more than 1.5 secs to aggressively lower the nose?
Try it next time you fly – but usually you have a few seconds before you stall, Vy is quite a bit higher than Vs. The one scenario where you have to be really be on a hair trigger is a Vx climb in a powerful aircraft, where the nose is much higher and the margin to the stall speed is very small.
But there is a massive difference to the R22 here. In a fixed wing aircraft, if you stall because you mishandle a sudden engine failure you can usually correct by lowering the nose. Even if you ignore all the warning signs (pulling back more and more, mushy controls, pre-stall buffet and stall warner) you usually can still recover.
If the rotor in a helicopter gets too slow after a failure, it won’t autorotate and you crash. There is absolutely nothing the pilot can do at that point, and it can happen in ANY phase of flight.
And engines do not necessarily go with a bang. A sudden fuel stoppage (say, a ruptured hose, or blocked carburetor nozzle) is sudden but quiet, literally…
It’s really no worse than a glider on a winch launch if the winch fails. You’re pitched up at about 50 degrees nose up, you must immediately start lowering the nose, you can’t be waiting for 4-5 seconds of “startle effect”, you have to immeditately and instinctively get the nose down, then wait for the airspeed to build back up before trying to do anything like a turn.
You can’t really miss a rope break. Much worse is when the winch slowly loses power – but even then, you notice by wind noise if not by airspeed indicator. I really think it’s much worse when the engine screams full power at you while also not putting out full power, finding out what’s wrong might just take the bad part of half a second.
Remind me to never enter such death traps.
Vx climbs, winch launches and climb below Vyse are flight phases which last less than a minute, and whenever you do one you normally brief the actions you will take if the/an engine fails, so reaction times are short.
Quite different from reacting to the unexpected in cruise. 2-5 seconds is more normal, based on my observation when instructing and my own times when having unexpected engine failures in flight (1x real, 1x own idiocy in a twin, 1x a very brave instructor shut off the fuel on one in a twin)
Latest news in Nice-Matin newspaper (yesterday’s) did confirm an engine failure and a mayday call before impacting the Sea. The BEA did recover the wreckage from the sea, just 30m deep at this place, before the underwater cliff just nearby.
