R22 down at Cannes
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From: LFMD
R22 down at Cannes
An R22 crashed into the sea just off Cannes yesterday afternoon, killing the instructor and student on board. I'd watched it take off a few minutes earlier. An eye-witness, who happened to be a pilot, said clearly that the rotor was not turning. So in all probability classic R22 rotor stall. Very sad.
https://aviation-safety.net/wikibase/349815
https://aviation-safety.net/wikibase/349815
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From: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
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From: LFMD
No, routine R22 bashing. Practically all my helicopter time is on R44s, which are very nice flying machines - despised primarily by those whose turbine flying time is paid for by someone else.
But when the engine stops, you literally have 1.5 seconds to drop the collective on an R22 - including the time it takes you to realise and react. When people talk about EFATO training in fixed-wing, they assume (iirc) 3 seconds to even realise something has gone wrong. The truth can evidently be less or nobody would have survived an R22 engine failure. But there have nevertheless been numerous fatals when people (including, as in this case, experienced instructors) didn't get the collective down fast enough.
But when the engine stops, you literally have 1.5 seconds to drop the collective on an R22 - including the time it takes you to realise and react. When people talk about EFATO training in fixed-wing, they assume (iirc) 3 seconds to even realise something has gone wrong. The truth can evidently be less or nobody would have survived an R22 engine failure. But there have nevertheless been numerous fatals when people (including, as in this case, experienced instructors) didn't get the collective down fast enough.
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From: UK
I seem to remember reading somewhere that an actual "real engine failure" in an R22 is extremely rare, with only a handful having ever occurred. Most "engine failures" are, in reality fuel exhaustion or carb heat issues (ie pilot error).
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From: California
"Classic" R22 rotor stall is apt, as that was a problem waaaaaaay back when the machine was new to the world. Nowadays, you'd have to reeeeally be distracted to let one stall,... especially at sea level.
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From: LFMD
Nowadays, you'd have to reeeeally be distracted to let one stall
In this case there was an experienced instructor with loads of R22 time on board. Didn't help.
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From: South East Asia
I understand they had just taken off. I trained out of Cannes a bit (type rating). Heading toward the sea is normal to transition either east or west, (I forgot) to reach the training areas north of the airport. Do you recon a training event gone bad or an unexpected failure?
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From: LFMD
Helicopters use 22/04 (04 that day) with a traffic pattern out over the sea, so their flight was normal pattern work. If they were practising autos, they wouldn't have started there. And the instructor would have had her hand on the collective spring-loaded to push in case the student wasn't quick enough. So the most likely case is some kind of engine failure.
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From: Geneva, Switzerland
Last edited by atakacs; 13th January 2024 at 14:58.
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From: California
I don't follow. Have they made seconds longer since 1985? You still have <2 seconds to realise what has happened, get your hand back on the collective if you happen to be tuning radios etc, and get it down. Maybe you're more aware of it now, but thats all.
In this case there was an experienced instructor with loads of R22 time on board. Didn't help.
In this case there was an experienced instructor with loads of R22 time on board. Didn't help.
If you're saying the accident was the result of "classic rotor stall" then that is an engine still running accident, which generally requires the pilot to be "not paying attention" to happen.
Plus, if it was a sudden engine failure, the problem isn't so much getting the collective down in time (as we are trained diligently for that) but if the student raised the collective instead, THAT could most certainly cause the blades to stop!
,...and the R22 came out in '79.
Last edited by Robbiee; 13th January 2024 at 15:33.
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From: EGDC
You can only get the rotor to stall if the Nr is very low - this can be power off (and failing to lower the collective following a loss of power) - or power on (massive overpitching).
In a circuit pattern it is most likely to be a practice (or real) engine failure with late intervention to lower the lever.
In a circuit pattern it is most likely to be a practice (or real) engine failure with late intervention to lower the lever.
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From: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
Originally Posted by [email protected]
You can only get the rotor to stall if the Nr is very low - this can be power off (and failing to lower the collective following a loss of power) - or power on (massive overpitching).
In a circuit pattern it is most likely to be a practice (or real) engine failure with late intervention to lower the lever.
In a circuit pattern it is most likely to be a practice (or real) engine failure with late intervention to lower the lever.
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From: PLanet Earth
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From: South East Asia
Originally Posted by [email protected]
You can only get the rotor to stall if the Nr is very low
The thing to remember is that lift is a function of velocity squared (L = 1/2 ρ V2 × S × CL) for every 20% RRPM lost you lose 40% lift.
Thus the problem with low inertia rotors, the speed at which you go into trouble is also squared.
fast RRPM loose will give you the feeling that the seat is falling from under you and if you instinctively raise the collective thinking it’s a downdraft, you are done!
you can call that a stall if you want, although this is more a fixed wing term.
Also I would say that recovering a lot of RRPM that you lost entering late into the auto in the R22 can be a quite a trip.
I did that ab initio early in my training, waited the whole glide down with the lever fully limit down looking mostly at the RRPM gauge.
It did make it to the green again as it was time to flare not a second too early, good wake call that day.
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From: Den Haag
for every 20% RRPM lost you lose 40% lift.
Base it on the actual Nr, so compared to 100% Nr the lift (purely as a function of Nr, and not CL with the varying pitch and AoA):
80% = 64%
60% = 36%
40% = 16%
But the loss is exponential (by definition) and, so, dramatic!
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From: England
You are correct if you aim to do nothing but lower the lever however remember that when in forward flight you can trade airspeed for RRPM by flaring. In fact in the cruise it is possible to not lower the lever for some seconds even in a low inertia system with the steady application of aft cyclic should your left hand be busy as you describe and not on the collective. We sadly do not seem to teach and stress the importance of how to manage the energy stored in ones rotor to students as much as we did in the past.