HV Curve engine failure question
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HV Curve engine failure question
So you're conducting a long line operation, hovering at approx 2-400ft and the engine quits. What do you do?
Just interested in what some of the experienced long liners think out there as i have heard different ideas and opinions on this one
Just interested in what some of the experienced long liners think out there as i have heard different ideas and opinions on this one
Last edited by Scrawny; 14th Sep 2010 at 20:58. Reason: spelling
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You'd better know exactly what you're going to do, and what the symptoms are of an engine failure.
No time to make it up in those conditions.
And I'll be interested to see the responses - I have an idea of what they'll be.
No time to make it up in those conditions.
And I'll be interested to see the responses - I have an idea of what they'll be.
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No correction with cyclic*, DUMP THE POLE, haul it in in the usual place (no check, just haul it in), try to avoid the load.
*400 feet is the top of the HV curve for the 206, but you're longlining, so you're likely in a place where speed won't help anyway. In any case, I'm very comfortable with a vertical descent.
As Shawn says, learn to recognise the symptoms. The type of machine determines the recognition time - 500 not so much, 206L, time enough to make a coffee
Phil
*400 feet is the top of the HV curve for the 206, but you're longlining, so you're likely in a place where speed won't help anyway. In any case, I'm very comfortable with a vertical descent.
As Shawn says, learn to recognise the symptoms. The type of machine determines the recognition time - 500 not so much, 206L, time enough to make a coffee
Phil
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Mmmm ...
....time enough to make a coffee ...
It'd have to be a 'short black' though .....
....time enough to make a coffee ...
It'd have to be a 'short black' though .....
Last edited by spinwing; 19th Sep 2010 at 22:13.
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I have thought about this a lot as its where i spend most of my time while flying, but......I am keen to what others have to say and think on my theorys.
Number 1 is have a longer rather than shorter line on, i like a 200ft line minimum.
reason being i think i would have more time to react, especially in mountainous terrain, it may make the difference between clearing the trees and making it out over a valley and getting some sort of auto together or not,
A friend of mine questioned me on my longer (200ft) line i was using, granted a 100ft or even a 50ft would have done the job, but he had a GOV failure on a 150ft line and ended up 4ft off the ground trying to get RRPM sorted with a 200ft he reckons he would have been 54ft, who knows.
But other than that there is **** all time to sort it all out as too whats going on, but would probably be just lowering the club, to conserve whatever RRPM was left and pulling the thing out of the deck to cushon the impact, and as stated earlier if there was some hope of getting out over a valley of desending terrain i would go for that and get some forward speed for a flare.
If over flat ground any fwd speed would probably be of help but over trees straight down would be my choice with aft cyclic on contact with the greenery, bearing in mind the gurus say an A/S under 40kts is not much help in the flare.
Others thoughts on this would be read with interest as its a very valid and not much talked about topic.
all this aside i have talked to a grey haired gentleman pilot friend that had a engine failure in a 206 picking a load off the ground with a 100 ft line and he reckons the first he knew about it he was on the ground upside down..... that quick
Number 1 is have a longer rather than shorter line on, i like a 200ft line minimum.
reason being i think i would have more time to react, especially in mountainous terrain, it may make the difference between clearing the trees and making it out over a valley and getting some sort of auto together or not,
A friend of mine questioned me on my longer (200ft) line i was using, granted a 100ft or even a 50ft would have done the job, but he had a GOV failure on a 150ft line and ended up 4ft off the ground trying to get RRPM sorted with a 200ft he reckons he would have been 54ft, who knows.
But other than that there is **** all time to sort it all out as too whats going on, but would probably be just lowering the club, to conserve whatever RRPM was left and pulling the thing out of the deck to cushon the impact, and as stated earlier if there was some hope of getting out over a valley of desending terrain i would go for that and get some forward speed for a flare.
If over flat ground any fwd speed would probably be of help but over trees straight down would be my choice with aft cyclic on contact with the greenery, bearing in mind the gurus say an A/S under 40kts is not much help in the flare.
Others thoughts on this would be read with interest as its a very valid and not much talked about topic.
all this aside i have talked to a grey haired gentleman pilot friend that had a engine failure in a 206 picking a load off the ground with a 100 ft line and he reckons the first he knew about it he was on the ground upside down..... that quick
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And that's the problem - time! There's a lot going on, watching the load, listening to the gearbox, etc. If an engine quits, you won't have time to get forward speed - it will even take 2 or 3 seconds to get your head inside the door and make sense of the instruments - far too late!
There's a good case for thinking about doing engine offs with your head out of the door.
Phil
There's a good case for thinking about doing engine offs with your head out of the door.
Phil
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Phil,
I talked with one of the utility guys where I used to work. Because the USFS requires a minimum of 6 hours of longline training per year per pilot, what he would do every spring is practice engine failures at 150 feet. He had been doing this for over 20 years and hasn't had a engine failure yet. His feeling was that the year he didn't do this practice would be the year he had an engine failure. Plus since he was working a 150 foot line, 150 feet would be the worst case scenario. And since engine failures seem to happen during or immediately after a major power increase, his thoughts were that he would also have a full bucket when it happened.
First of all he was in a 212, and as I understand it, he has refused to do fire work in a 412. His technique was to immediately drop the collective and dump the load. Try to get at least a little forward movement with the cyclic. Passing about 75 feet AGL, horse back on the cyclic to flare and build up the rpm level off and cushion the landing. He would do this to a full touchdown. The time I flew with him he always had enough energy left to pick the machine back up and turn it at least 180 degrees. His theory was that you keep pedaling until ALL the dust settles.
I talked with one of the utility guys where I used to work. Because the USFS requires a minimum of 6 hours of longline training per year per pilot, what he would do every spring is practice engine failures at 150 feet. He had been doing this for over 20 years and hasn't had a engine failure yet. His feeling was that the year he didn't do this practice would be the year he had an engine failure. Plus since he was working a 150 foot line, 150 feet would be the worst case scenario. And since engine failures seem to happen during or immediately after a major power increase, his thoughts were that he would also have a full bucket when it happened.
First of all he was in a 212, and as I understand it, he has refused to do fire work in a 412. His technique was to immediately drop the collective and dump the load. Try to get at least a little forward movement with the cyclic. Passing about 75 feet AGL, horse back on the cyclic to flare and build up the rpm level off and cushion the landing. He would do this to a full touchdown. The time I flew with him he always had enough energy left to pick the machine back up and turn it at least 180 degrees. His theory was that you keep pedaling until ALL the dust settles.
Because the USFS requires a minimum of 6 hours of longline training per year per pilot
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So understand one method is to dump the collective ASAP, release the load and pull the collective through the roof just before impact. But what about some people i hear talk about nosing forward to see if you can get some sort of speed to do a flare. I have heard that if you don't reach x speed then the flare doesn't work therefore pointless attempting?
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Shawn, a little cryptic there. Would love to hear your thoughts as i hear you are on of the main men on this topic?
Phil, head out of the door on landing? Guillotine springs to mind? or have i misread?
Phil, head out of the door on landing? Guillotine springs to mind? or have i misread?
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Problem as i understand it, and someone please correct me if i,m wrong, is that if you nose over to much when the engine quits the machine may tuck its nose over to a unrecoverable attitude.
With the engine stopping and the down collective the disc will flap forward dropping the nose, if a big fwd cyclic input was done at the same time it may put the A/C in a nose down unrecoverable attitude.
Fwd cyclic also reduces RRPM, but can see the advantage of some fwd speed if Terrain permits as it would help with depth perception on the pitch pull.But i think that would be all.
I remember reading a article on low level engine failures in a Heli ops mag i think, the article was called Cyclic Back and that was the general angle of the article. Cyclic back in a low level power loss situation, it was written after several bad accidents with police 500s in the states, might try and find that mag i think i still have it somewhere
With the engine stopping and the down collective the disc will flap forward dropping the nose, if a big fwd cyclic input was done at the same time it may put the A/C in a nose down unrecoverable attitude.
Fwd cyclic also reduces RRPM, but can see the advantage of some fwd speed if Terrain permits as it would help with depth perception on the pitch pull.But i think that would be all.
I remember reading a article on low level engine failures in a Heli ops mag i think, the article was called Cyclic Back and that was the general angle of the article. Cyclic back in a low level power loss situation, it was written after several bad accidents with police 500s in the states, might try and find that mag i think i still have it somewhere
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Gordy, I was told it was 6 hours. But that was several years ago and I have never looked at the USFS book on that subject.
What Jim told me on the forward cyclic was for few reasons. One, considering what the worst case scenario is, you are most likely over water. And most likely deeper than you would like to be. 2nd was that it would give him a better view of his touch down area. And 3rd, helps him to keep the helicopter from moving backwards to sideways on touchdown. From what I saw he lowered the nose no more than about 5 degrees. Plus that is the one nice thing about the 212. The rotor disk stores a lot of energy.
What Jim told me on the forward cyclic was for few reasons. One, considering what the worst case scenario is, you are most likely over water. And most likely deeper than you would like to be. 2nd was that it would give him a better view of his touch down area. And 3rd, helps him to keep the helicopter from moving backwards to sideways on touchdown. From what I saw he lowered the nose no more than about 5 degrees. Plus that is the one nice thing about the 212. The rotor disk stores a lot of energy.
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Hi Rick - I trust you are up to no good?
That was the reason I mentioned no correction - aside from what you would have to do to sort the nose dropping problem. I can see the thinking that if the engine is going to fail it would be in a high power change situation, but I have had 2 in the cruise before now, and one in the hover taxi! Go figure.
Personally I wouldn't go for speed at all - depending on the machine, and if I got the collective down quick enough (you would only need the speed for a flare to bring the RPM up). In a 206 (or similar), you might not have enough control power to move the disk anyway, as it might not be loaded enough to produce the force you need. A 412/407/AS 350 would be a different story.
Scrawny - the check is there to protect the gearbox mountings as I understand it - on the 407, the check is simply a pause.
Dennis Venturi did an article about this in Helicopters mag a few years ago. He was using the principle of dynamic stall (as mentioned by NASA) where a quick pull up on an aerofoil produces a tiny vortex that moves from the leading edge to the rear and keeps the airflow to the surface (this is presumably why retreating blade stall doesn't flip the machine over). In other words, you can go beyond the basic stall for a second or two if you haul everything in at once. He reckoned that in a 206, it would produce about double the lift.
Phil
That was the reason I mentioned no correction - aside from what you would have to do to sort the nose dropping problem. I can see the thinking that if the engine is going to fail it would be in a high power change situation, but I have had 2 in the cruise before now, and one in the hover taxi! Go figure.
Personally I wouldn't go for speed at all - depending on the machine, and if I got the collective down quick enough (you would only need the speed for a flare to bring the RPM up). In a 206 (or similar), you might not have enough control power to move the disk anyway, as it might not be loaded enough to produce the force you need. A 412/407/AS 350 would be a different story.
Scrawny - the check is there to protect the gearbox mountings as I understand it - on the 407, the check is simply a pause.
Dennis Venturi did an article about this in Helicopters mag a few years ago. He was using the principle of dynamic stall (as mentioned by NASA) where a quick pull up on an aerofoil produces a tiny vortex that moves from the leading edge to the rear and keeps the airflow to the surface (this is presumably why retreating blade stall doesn't flip the machine over). In other words, you can go beyond the basic stall for a second or two if you haul everything in at once. He reckoned that in a 206, it would produce about double the lift.
Phil
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Phil,
Absolutely! My season is done and since the machine is going in for maintenance, I am currently looking for another job. I have had 8 engine failure events over the years. A mis-spent youth, trying to build flight time. The things we do when we are young and dumb and full of ***. All but one were in the takeoff portion of flight. What I got from Jim was that this was the worst possible place it could happen in. So to be prepared that is where he practiced it. The theory being if he could handle it there, every place else would be a snap. As for the forward movement, Jim's comment because of the terrain they normally have under them when working fires, he wanted to ensure that the helicopter was not going backwards or sideways. It must be working, because the last time I talked with Jim, he still hadn't had an engine failure fighting fires.
Absolutely! My season is done and since the machine is going in for maintenance, I am currently looking for another job. I have had 8 engine failure events over the years. A mis-spent youth, trying to build flight time. The things we do when we are young and dumb and full of ***. All but one were in the takeoff portion of flight. What I got from Jim was that this was the worst possible place it could happen in. So to be prepared that is where he practiced it. The theory being if he could handle it there, every place else would be a snap. As for the forward movement, Jim's comment because of the terrain they normally have under them when working fires, he wanted to ensure that the helicopter was not going backwards or sideways. It must be working, because the last time I talked with Jim, he still hadn't had an engine failure fighting fires.
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As I suspected - the best advice is to not touch the cyclic from those heights. There's no need, and you're not going to get enough forward speed for any flare to have an effect on your flight path.
Lower the collective and be ready to pull it all the way to the top as you get close to the ground.
But the important thing is to know what the symptoms of the engine failure are, and react without question.
Most folks who've had engine failures in helicopters were more than just a bit surprised at the failure, regardless of where the failure happened. I know for the three I've had, they were all very unexpected. So don't expect the normal indications - know what the real symptoms are (yaw, sinking feeling, etc.) and don't depend on horns and lights.
An extra half-second of time will make all the difference in terms of surviving.
Lower the collective and be ready to pull it all the way to the top as you get close to the ground.
But the important thing is to know what the symptoms of the engine failure are, and react without question.
Most folks who've had engine failures in helicopters were more than just a bit surprised at the failure, regardless of where the failure happened. I know for the three I've had, they were all very unexpected. So don't expect the normal indications - know what the real symptoms are (yaw, sinking feeling, etc.) and don't depend on horns and lights.
An extra half-second of time will make all the difference in terms of surviving.
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A question?
A question from a new pilot:
Does 'not touching the cyclic and just using the collective to cushion' also apply to the low inertia blade systems of the robbos? (obviously this is hyperthetical as robbos dont get used very much for long lining)
Cheers
Does 'not touching the cyclic and just using the collective to cushion' also apply to the low inertia blade systems of the robbos? (obviously this is hyperthetical as robbos dont get used very much for long lining)
Cheers