EOLs
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Succesfull EOL
I believe this is a Sycamore, pic take in 1989 near Kununurara. I think story goes, Engine failure, succesfull auto but blade strike. Company base in Adelaide and new engine + blades trucked up, road so rough that new blades damaged in transit, Airframe abandoned.
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Dennis,
I would say your run through was about right. How much check lever at the end of the flare is going to be type specific depending on inertia: the best comparison is between the R22 and the B206. AS is also more critical with the low inertia machines IMO, because you are using the KE to power the flare and cushion. Too little AS provides not enough KE, too much AS is hard to get rid of in the flare.
Someone (ex mil, I guess) was saying how the non military world did not seem to do EOLs. I suspect that would be your experience if you only were exposed to twin engine training/operations. Most ME heles have full training EOLs banned in their AFMs. EOLs are a requirement of all S/E skill tests in the UK. I guess there is a risk assessment in there that EOL for ME is less likely and the potential repair bill for practice EOLs correspondingly greater.
For many years I flew just MEs and EOLs got remote. I have recently started flying S/E again and feel reassured to have that extra tool back in practice.
I would say your run through was about right. How much check lever at the end of the flare is going to be type specific depending on inertia: the best comparison is between the R22 and the B206. AS is also more critical with the low inertia machines IMO, because you are using the KE to power the flare and cushion. Too little AS provides not enough KE, too much AS is hard to get rid of in the flare.
Someone (ex mil, I guess) was saying how the non military world did not seem to do EOLs. I suspect that would be your experience if you only were exposed to twin engine training/operations. Most ME heles have full training EOLs banned in their AFMs. EOLs are a requirement of all S/E skill tests in the UK. I guess there is a risk assessment in there that EOL for ME is less likely and the potential repair bill for practice EOLs correspondingly greater.
For many years I flew just MEs and EOLs got remote. I have recently started flying S/E again and feel reassured to have that extra tool back in practice.
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Sounds picture perfect for light singles Dennis. The same overlay technique should be used for teaching power recoveries and touchdowns - but of course I respect that you've been flying longer than I've been walking 
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I used to teach an opposite approach. Higher A/S around 70kts, RRPM bottom of the green, just above the horn. During the flare, LOWER collective fully, hold until you are about to fall thru, level, settle then pull.
This accomplishes several things; first you can flare more aggressively without ballooning up ie quickstop, which reduces your ground run. Most of the time you will be practicing this on a paved surface, but real world slower touchdown speed will keep you from rolling over. Second you are guarenteed to see a large increase of RRPM so you have more to cushion with at the bottom. Thirdly and most important for low inertia systems is that with zero pitch you reduce your rotor decay between leveling settling and pulling.
I've taught this technique to 20+ students(including DPE/FAA examiners) and it works like a charm in the 22/44/300. Only difference is the 44 requires less aggressive flare and in the 300 you don't have to play with the lever as much. The only other variable is how high you can level and still get away with a smooth touchdown. 22 being the lowest <8ft, in the 300 you can get away with 10 maybe 12ft and the 44 15-20ft as long as you wait to cushion.
DISCLAIMER: This technique only works with 2 people in the aircraft. The reduced weight of solo ops requires you to maintain higher RRPM throughout the manuver, because RRPM will not significantly increase during flare.
This accomplishes several things; first you can flare more aggressively without ballooning up ie quickstop, which reduces your ground run. Most of the time you will be practicing this on a paved surface, but real world slower touchdown speed will keep you from rolling over. Second you are guarenteed to see a large increase of RRPM so you have more to cushion with at the bottom. Thirdly and most important for low inertia systems is that with zero pitch you reduce your rotor decay between leveling settling and pulling.
I've taught this technique to 20+ students(including DPE/FAA examiners) and it works like a charm in the 22/44/300. Only difference is the 44 requires less aggressive flare and in the 300 you don't have to play with the lever as much. The only other variable is how high you can level and still get away with a smooth touchdown. 22 being the lowest <8ft, in the 300 you can get away with 10 maybe 12ft and the 44 15-20ft as long as you wait to cushion.
DISCLAIMER: This technique only works with 2 people in the aircraft. The reduced weight of solo ops requires you to maintain higher RRPM throughout the manuver, because RRPM will not significantly increase during flare.
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Comments, please!
OK, I've read all the posts. I have one question that bothers me a bit.
Higher RRPM gives a greater rate of descent. So, in the flare, wouldn't the best practice be to not build up too much of it? That gives a better arrest rate of forward speed, which, in turn, reduces the risk of rolling over.
Some of my instructors have practiced this and made the autorotations at very low RRPM - in a 206 90% and 90kts - which takes you a really long way past your expectations, followed by a long flare with a fairly high amount of collective pitch and a really smooth touchdown with zero forward speed. Just before touchdown, the RRPM has been a bit below 100% indicating a slight buildup for good margins in the actual cushioned ground contact.
I understand that this is not possible to the same extent in helicopters with low inertia rotor systems, but at least not build up RRPM to the red line or above.
Higher RRPM gives a greater rate of descent. So, in the flare, wouldn't the best practice be to not build up too much of it? That gives a better arrest rate of forward speed, which, in turn, reduces the risk of rolling over.
Some of my instructors have practiced this and made the autorotations at very low RRPM - in a 206 90% and 90kts - which takes you a really long way past your expectations, followed by a long flare with a fairly high amount of collective pitch and a really smooth touchdown with zero forward speed. Just before touchdown, the RRPM has been a bit below 100% indicating a slight buildup for good margins in the actual cushioned ground contact.
I understand that this is not possible to the same extent in helicopters with low inertia rotor systems, but at least not build up RRPM to the red line or above.
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TET
Your string and weight example is a demonstration of the conservation of angular momentum...not Coriolis Effect ! (or possibly the Red effect)
Your string and weight example is a demonstration of the conservation of angular momentum...not Coriolis Effect ! (or possibly the Red effect)
FAA Basic Helicopter Handbook p 14/15, a couple of excerpts.
“Coriolis Effect, when the blade of a three bladed rotor system flaps upward, the centre of mass of that blade moves closer to the axis of rotation and blade acceleration takes place and conversely.....To a lesser extent in a two bladed system when it is underslung....
The tendency of a rotor system to increase or decrease its velocity in its plane of rotation due to mass movement is known as Coriolis Effect, named for the mathematician who made studies of forces generated by radial movements of mass on a rotating plane...”
The tendency of a rotor system to increase or decrease its velocity in its plane of rotation due to mass movement is known as Coriolis Effect, named for the mathematician who made studies of forces generated by radial movements of mass on a rotating plane...”
More red please.
tet
TET - raise the lever to get the lift, the flapping and the conservation of angular momentum and you increase drag as well as lift so the blades slow down because the engine isn't driving them any more.
Lever up in auto = Nr down.
Lever up in auto = Nr down.
Nemo Me Impune Lacessit
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rotor pedals to line the skids up in the direction of the ground run.
Flare>rapid check>level>cushion on with remaining collective.
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TET - raise the lever to get the lift, the flapping and the conservation of angular momentum and you increase drag as well as lift so the blades slow down because the engine isn't driving them any more.
Lever up in auto = Nr down.
Lever up in auto = Nr down.
Now, here we are sitting fat dumb and happy with a decaying nr, (admittedly with a higher drag configuration on the M/R than during flat pitch and descent mode) settling and awaiting the cushioning pull of the remaining collective. No arguments from me at all.
Each action, the flare and the quick click on the lever, has the reaction of coning the blades and thus moving their mass inwards, that is why they increase in RPM. the trick is to make sure that the static auto RRPM setting is right, not too high or that increase may be over the redline.
my shout or yours?
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Mmm ...
That Sycamore has been there for at least 40+ years that I know of .... can't for the life of me remember the details ... lost way too many of those memory cell thingys...
That Sycamore has been there for at least 40+ years that I know of .... can't for the life of me remember the details ... lost way too many of those memory cell thingys...
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The sequence of flare / level / collective check is very much type dependent, and also has a lot to do with the CG position relative to the mast. A forward CG will allow use of the collective check to level the helicopter, as the CG and thrust vector (small as it is ) want to align.
For teetering rotor machines, trying to level with the cyclic is not as effective as it is in fully articulated types, as the small change in tilt of the thrust vector produces very little effect. For that reason, using collective to assist in leveling is most effective in those machine. But a Bell 206 or R-44 will normally have much more effect in leveling using collective than an R-22 because the CG is further from the mast. A 206 loaded with an aft CG (lots of stuff in the baggage compartment and a single pilot, for example) may not level using collective only, so Beware!
The only other things I'd like to add to this discussion is that the purpose of the flare is to stop the rate of descent - anything else that happens is a beneficial side effect.
For teetering rotor machines, trying to level with the cyclic is not as effective as it is in fully articulated types, as the small change in tilt of the thrust vector produces very little effect. For that reason, using collective to assist in leveling is most effective in those machine. But a Bell 206 or R-44 will normally have much more effect in leveling using collective than an R-22 because the CG is further from the mast. A 206 loaded with an aft CG (lots of stuff in the baggage compartment and a single pilot, for example) may not level using collective only, so Beware!
The only other things I'd like to add to this discussion is that the purpose of the flare is to stop the rate of descent - anything else that happens is a beneficial side effect.
TET - the flare increases the Nr - the pull, check or click on the collective does the opposite.
If you check whilst flaring, the flare effect may well overcome the extra drag from the check but raising the lever does not increase Nr no matter how quickly you do it.
It is feasible, with an aft C of G, that raising the lever will bring the nose up slightly effectively giving an increase in the flare effect but it is still flare effect that is raising the Nr.
If you check whilst flaring, the flare effect may well overcome the extra drag from the check but raising the lever does not increase Nr no matter how quickly you do it.
It is feasible, with an aft C of G, that raising the lever will bring the nose up slightly effectively giving an increase in the flare effect but it is still flare effect that is raising the Nr.
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Fareast
It was well off your track,I put the Sycamore roughly at 70nms at 218degrees from Kununurra from memory
Amazing fabric covered blades like the wing of a fabric covered airplane. How was the auto re inertia and so on? I bet the hot radial could take a bit of starting sometimes post auto.
spinwing
In another pic I have you can see the trunk of the tree he collected, still standing there cut off at blade height, also some of the engine.
It was well off your track,I put the Sycamore roughly at 70nms at 218degrees from Kununurra from memory
Amazing fabric covered blades like the wing of a fabric covered airplane. How was the auto re inertia and so on? I bet the hot radial could take a bit of starting sometimes post auto.
spinwing
In another pic I have you can see the trunk of the tree he collected, still standing there cut off at blade height, also some of the engine.
.
Ciao Dennisimo!
I wonder if you can even count the number of engine offs you have performed - it must be in the multiple thousands by now - and I am sure you're procedure has brought you down safe and sound every time!
Great thread Maestro!
Mine was also in a 206A (converted to a B) which was eventually bought by Dennis Kenyon, G-AYTF. According to PPRuNer TRC it was caused by a failure in the turbine's P2 line.
We were at approx. 700ft agl and with no place to go except straight ahead where, mercifully, there was an open field. The field had fairly large furrows running roughly east-west and we were southbound out of the Team Lotus headquarters at Hetel and therefore set up to land across the furrows.
Sincerely, I can't recall whether Bob introduced a touch of collective prior to levelling but, given the brevity of our descent and the available time, I don't think so.
There was no possibility of permitting any forward speed, with forward momentum the furrows would have tipped the little Ranger on its back! For this reason the flare was extreme, it seemed as if we were almost vertical at one point but, we levelled and cushioned with zero forward speed, a gentle touchdown and the 'Dancer' (G-AYTF) was intact. It was the Colonel at his best!
This incident is recalled on another thread and one thing I learnt from it is that in a genuine scenario, unless this procedure runs through your veins, well - scrambled eggs come to mind!
At Point 4. the 206's nose-high attitude was pronouned just prior to a 'smart' (rapid) level leading into a zero-forward-speed cushion.
With Dennis' one time chief flying instructor 'Antonio' (Tony 'Nobby' Clarke) I was taught the 'collective-in-flare' technique but as an option to increase/decrease Nr according to the intended landing profile, zero-stop, run on, etc.
In the days when I used to fly commercially I regularly attended refresher courses in the US and have to voice my admiration for the various instructors I encountered there. They were among some of the most professional and well disciplined aviators I have come across, with heaps of proficiency in power-off landings, and which familiarity was conveyed with confidence during their training exercises.
Here for your perusal, the Alabama State Troopers practicing autos in one of their Kiowas.
S.
Ciao Dennisimo!
I wonder if you can even count the number of engine offs you have performed - it must be in the multiple thousands by now - and I am sure you're procedure has brought you down safe and sound every time!
Great thread Maestro!
My only EOL for real was in an AB206A and the terrain did not allow for any run-on.
We were at approx. 700ft agl and with no place to go except straight ahead where, mercifully, there was an open field. The field had fairly large furrows running roughly east-west and we were southbound out of the Team Lotus headquarters at Hetel and therefore set up to land across the furrows.
Sincerely, I can't recall whether Bob introduced a touch of collective prior to levelling but, given the brevity of our descent and the available time, I don't think so.
There was no possibility of permitting any forward speed, with forward momentum the furrows would have tipped the little Ranger on its back! For this reason the flare was extreme, it seemed as if we were almost vertical at one point but, we levelled and cushioned with zero forward speed, a gentle touchdown and the 'Dancer' (G-AYTF) was intact. It was the Colonel at his best!
This incident is recalled on another thread and one thing I learnt from it is that in a genuine scenario, unless this procedure runs through your veins, well - scrambled eggs come to mind!
At Point 4. the 206's nose-high attitude was pronouned just prior to a 'smart' (rapid) level leading into a zero-forward-speed cushion.
With Dennis' one time chief flying instructor 'Antonio' (Tony 'Nobby' Clarke) I was taught the 'collective-in-flare' technique but as an option to increase/decrease Nr according to the intended landing profile, zero-stop, run on, etc.
In the days when I used to fly commercially I regularly attended refresher courses in the US and have to voice my admiration for the various instructors I encountered there. They were among some of the most professional and well disciplined aviators I have come across, with heaps of proficiency in power-off landings, and which familiarity was conveyed with confidence during their training exercises.
Here for your perusal, the Alabama State Troopers practicing autos in one of their Kiowas.
S.
EOLs in a 206 are hardly challenging, watch an R22 doing them with a couple of fatties inside and you will see "half a crown sixpence" 
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I remember the Sycamore as well. Quite the most specialised EOL technique compared to any other helicopter I've ever flown.
Best technique for the R22 is level the skids and apply collective at the same time so that the skids achieve the level attitude at the moment of touchdown. Works for most other types as well if you fly multiple types, although they all have their own ideal techniques that may work better depending on blade inertia.
Best technique for the R22 is level the skids and apply collective at the same time so that the skids achieve the level attitude at the moment of touchdown. Works for most other types as well if you fly multiple types, although they all have their own ideal techniques that may work better depending on blade inertia.
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Not sure if anyone is interested in seeing a 'perfectly' executed auto but .. in case you are .. here you go:
Pretty much how I seem to remember my base checks.
I went through the clip using the pause button intermittently in an effort to discover evidence of collective application in the flare and decided that I couldn't decide! But I think not.
Re: 'checking in the flare' would that procedure not be ideally suited to something like the Hughes 500 where rrpm can deplete (from what I am told) quite rapidly?
Earl
Pretty much how I seem to remember my base checks.
I went through the clip using the pause button intermittently in an effort to discover evidence of collective application in the flare and decided that I couldn't decide! But I think not.
Re: 'checking in the flare' would that procedure not be ideally suited to something like the Hughes 500 where rrpm can deplete (from what I am told) quite rapidly?
Earl