Engine offs to the ground
Join Date: Jan 2003
Location: W'n. USA--full time RV
Posts: 132
Likes: 0
Received 0 Likes
on
0 Posts
Right, thanks. Now: common mistakes??
Shawn Coyle:
I don't think anybody answered your question on R22 EOL's to hard surfaces; so, IME, that's the ONLY way they do them, except perhaps under the rare conditions when the ship won't slide. My counter-question: is there a substantial percentage of Non-R22 EOL practice to turf or dirt or (what else is soft?)?
(The widespread doctrine in f/w retractables is DO NOT, EVER, make a gear up landing on soft surfaces, for they tend to roll up under the belly and total the airframe, whereas hard (smooth) surfaces only grind off the lowest 1" of metal, which can be replaced.)
=====
Thomas coupling:
Thanks for the reassurance, maybe the crunch frequency is different in R22's; sounds like military pilots get MUCH more EOL practice than civilian!
However, I haven't given up on getting somebody to list major mistakes low-timers make; you mentioned also the difficulty of success because of wind, altitude, speed, surface, reaction time, D/N and adrenaline. To simplify discussion, let's discard wind (assume calm), specify LOTS of altitude (1000' AGL, so the descent is stabilized), hard smooth surface (spacious asphalt/concrete ), Nr stable 'til flare, Daytime, nerves of steel (no extra adrenaline).
Now what? If the Heli-rated solo pilot has these things all set & taken care of, what does he do WRONG most commonly that causes damage/injury? (That is, assuming it's largely a civilian pilot problem, where are the CFI's falling short in training emphasis?)
I realize you quit doing instruction some years back, and it was military equipment--given that, what flare-to-touchdown errors on the part of the student were you most alert for because the greatest number of students tried to destroy the aircraft with them? How can I most effectively focus my students' attention on the skills they need?
(Don't get me wrong, I do have a syllabus covering these topics--but I'm always looking for enhancements.)
I don't think anybody answered your question on R22 EOL's to hard surfaces; so, IME, that's the ONLY way they do them, except perhaps under the rare conditions when the ship won't slide. My counter-question: is there a substantial percentage of Non-R22 EOL practice to turf or dirt or (what else is soft?)?
(The widespread doctrine in f/w retractables is DO NOT, EVER, make a gear up landing on soft surfaces, for they tend to roll up under the belly and total the airframe, whereas hard (smooth) surfaces only grind off the lowest 1" of metal, which can be replaced.)
=====
Thomas coupling:
Thanks for the reassurance, maybe the crunch frequency is different in R22's; sounds like military pilots get MUCH more EOL practice than civilian!
However, I haven't given up on getting somebody to list major mistakes low-timers make; you mentioned also the difficulty of success because of wind, altitude, speed, surface, reaction time, D/N and adrenaline. To simplify discussion, let's discard wind (assume calm), specify LOTS of altitude (1000' AGL, so the descent is stabilized), hard smooth surface (spacious asphalt/concrete ), Nr stable 'til flare, Daytime, nerves of steel (no extra adrenaline).
Now what? If the Heli-rated solo pilot has these things all set & taken care of, what does he do WRONG most commonly that causes damage/injury? (That is, assuming it's largely a civilian pilot problem, where are the CFI's falling short in training emphasis?)
I realize you quit doing instruction some years back, and it was military equipment--given that, what flare-to-touchdown errors on the part of the student were you most alert for because the greatest number of students tried to destroy the aircraft with them? How can I most effectively focus my students' attention on the skills they need?
(Don't get me wrong, I do have a syllabus covering these topics--but I'm always looking for enhancements.)
Join Date: Sep 2001
Location: In the Haven of Peace
Age: 79
Posts: 600
Received 0 Likes
on
0 Posts
I did a few thousand EOls in the R22 (without the needles synchronised) back in the old ab-initio instructing days. Aircraft undamaged (honestly
)
As for engine failures; never had one for real in a single, but had a couple in twins, which is why I always do autos to a flare and power recovery in twins on an OPC.
)As for engine failures; never had one for real in a single, but had a couple in twins, which is why I always do autos to a flare and power recovery in twins on an OPC.
Join Date: Jul 2002
Location: uk
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
SAS and anyone else
I read somewhere (can't remember where) that it is possible to land the UH-1, cut the throttles, then lift the collective and there is enough inertia in the blades to lift the heli into the hover, yaw through 180 and land it again as smoothly as normal.
Question 1 - Do you know if this is this true?
Question 2 - Do you (or anyone else) think this make EOLs in a "big machine" less daunting and safer than in, say an R22, with a low inertia blade?
PS My biggest worry regarding real autos in the R22 is not the bit at the bottom but getting the lever down in the 1. something seconds that you need to!!!!
I read somewhere (can't remember where) that it is possible to land the UH-1, cut the throttles, then lift the collective and there is enough inertia in the blades to lift the heli into the hover, yaw through 180 and land it again as smoothly as normal.
Question 1 - Do you know if this is this true?
Question 2 - Do you (or anyone else) think this make EOLs in a "big machine" less daunting and safer than in, say an R22, with a low inertia blade?
PS My biggest worry regarding real autos in the R22 is not the bit at the bottom but getting the lever down in the 1. something seconds that you need to!!!!
Join Date: Dec 2002
Location: Yorkshire
Posts: 80
Likes: 0
Received 0 Likes
on
0 Posts
To give you an idea of the available intertia at the bottom in a Bell 47 EOL, I was recently told by an ex AAC instructor that the 'show-off' exercise to give students an idea of how much they had to play with, was:
EOL to a marked spot, lift off turn 90 degrees, move three yards, put her down again, lift off, turn, etc. with the challenge to complete all four corners of the square.
Not many made the fourth, but it was possible!
I'm sure this isn't a myth, as another AAC instructor told me the same story.
All very impressive, but with hydraulics engine driven (not off the transmission), there's no such thing as a practice for real....
EOL to a marked spot, lift off turn 90 degrees, move three yards, put her down again, lift off, turn, etc. with the challenge to complete all four corners of the square.
Not many made the fourth, but it was possible!
I'm sure this isn't a myth, as another AAC instructor told me the same story.
All very impressive, but with hydraulics engine driven (not off the transmission), there's no such thing as a practice for real....
Thread Starter
Join Date: Feb 2002
Location: england
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
NigD2,
Flare, flare and flare. Wait 5 seconds then lower the lever and you will still be flying in a R22. The RRPM can still be recovered as low as 75% possibilly lower. Not seen it below 80% myself.
PS. Don't try this at home.
Flare, flare and flare. Wait 5 seconds then lower the lever and you will still be flying in a R22. The RRPM can still be recovered as low as 75% possibilly lower. Not seen it below 80% myself.
PS. Don't try this at home.
Join Date: May 2001
Location: London
Posts: 528
Likes: 0
Received 0 Likes
on
0 Posts
Helo Teacher:
I'm afraid I'm a lot less sanguine than you about pilots' ability to get into autorotation after a sudden and complete engine failure in an R22.
In the case of a partial or gradual engine failure I'm sure there would be few problems, but where something like carb icing turns the engine off like a light, especially in the climb, I'm simply not convinced that the average person's recognition processes/reaction time are up to the job.
As to the engine-off landing, look at it this way. 1800 fpm is about 20mph. Even if you don't lift a finger, by the time the skids have splayed and the crumble zone has concertina-ed you're not looking at deadly force.
Once again, I'm talking about the R22 here. I'd happily zero-zero a 206 from 100 feet at 30 knots in the climb.
I'm afraid I'm a lot less sanguine than you about pilots' ability to get into autorotation after a sudden and complete engine failure in an R22.
In the case of a partial or gradual engine failure I'm sure there would be few problems, but where something like carb icing turns the engine off like a light, especially in the climb, I'm simply not convinced that the average person's recognition processes/reaction time are up to the job.
As to the engine-off landing, look at it this way. 1800 fpm is about 20mph. Even if you don't lift a finger, by the time the skids have splayed and the crumble zone has concertina-ed you're not looking at deadly force.
Once again, I'm talking about the R22 here. I'd happily zero-zero a 206 from 100 feet at 30 knots in the climb.
Senis Semper Fidelis
Join Date: Feb 2001
Location: Lancashire U K
Posts: 1,288
Likes: 0
Received 0 Likes
on
0 Posts
A brilliant man called Geof Day, on one of my annuals showed me just how far you can take the R22, being still full of the pages of every Heliflying book available I can tell you i thought I could pee faster than the rotor was going round, and still being here proves that it taught me a very good lesson, and just how long 5 seconds are 
Cool as a moosp
Join Date: Aug 2001
Location: Mostly Hong Kong
Posts: 802
Likes: 0
Received 0 Likes
on
0 Posts
Yes we'd all like to know about low rotor speed experiments, but I am REAL suspicious of experienced pilots who are able to take an aircraft to an extreme that is outside the normal operating envelope of the POE.
Yes, I have seen a Robinson factory test pilot take the RPM of an R22 low enough to widen my old eyes but they also know at which point the boom chop occurs from their flight test and computer simulation data. They are thus able to avoid it.
If a totally competent flight instructor chooses to explore the flight envelope beyond where the factory has gone, then he will one day find the aircraft's limitation by trial and error. And then it will be too late.
Please folks, let's not get into macho contests to see who has gone further than the next guy (And it is usually guys who do this stuff...) with his particular machine. Big cohones make big holes in the ground.
Yes, I have seen a Robinson factory test pilot take the RPM of an R22 low enough to widen my old eyes but they also know at which point the boom chop occurs from their flight test and computer simulation data. They are thus able to avoid it.
If a totally competent flight instructor chooses to explore the flight envelope beyond where the factory has gone, then he will one day find the aircraft's limitation by trial and error. And then it will be too late.
Please folks, let's not get into macho contests to see who has gone further than the next guy (And it is usually guys who do this stuff...) with his particular machine. Big cohones make big holes in the ground.
Join Date: Feb 2002
Location: Australia
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
The Real Thing........
Just read an interesting and relevant story from a book Called " Helicopters Will Take You Anywhere" written by Ron Newman, a well known and highly respected Australian Instructor..........[No not related to myself].....on page 136 he writes....
"Anyone who has had an engine failure at high power will tell you that the RPM decay and the yaw in a real engine failure are far greater than when simulating an engine failure by rolling off the throttle.
It doesn't matter how quickly you snap the throttle closed, it is still a gradual power reduction compared to an engine failure, particularly in a turbine engine where the turbine has to wind down from over 30,000 RPM.
I had a throttle cable jam at climb power in a Hughes 300 on a training flight, and as I couldn't lower the collective without causing an "overspeed" I had to continue climbing as I returned to the airport. By the time I reached the airport I had climbed to 4500' and at this point I got the student to pull the mixture out.
I have done thousands of practice autorotations but the severity of the yaw surprised me, and yet I knew it was coming"
Chaps, we are just practicing with one arm behind our back. If you are serious about teaching Engine Off's to the ground!!!!..............then do as the earlier posting suggested..........pull out the mixture or turn off the fuel...............
Only then are you serious.
Otherwise you are giving only false confidence..........
"Anyone who has had an engine failure at high power will tell you that the RPM decay and the yaw in a real engine failure are far greater than when simulating an engine failure by rolling off the throttle.
It doesn't matter how quickly you snap the throttle closed, it is still a gradual power reduction compared to an engine failure, particularly in a turbine engine where the turbine has to wind down from over 30,000 RPM.
I had a throttle cable jam at climb power in a Hughes 300 on a training flight, and as I couldn't lower the collective without causing an "overspeed" I had to continue climbing as I returned to the airport. By the time I reached the airport I had climbed to 4500' and at this point I got the student to pull the mixture out.
I have done thousands of practice autorotations but the severity of the yaw surprised me, and yet I knew it was coming"
Chaps, we are just practicing with one arm behind our back. If you are serious about teaching Engine Off's to the ground!!!!..............then do as the earlier posting suggested..........pull out the mixture or turn off the fuel...............
Only then are you serious.
Otherwise you are giving only false confidence..........
Last edited by Red Wine; 11th Feb 2003 at 14:50.
Join Date: May 2001
Location: London
Posts: 528
Likes: 0
Received 0 Likes
on
0 Posts
...may I also suggest that for realism, you set out on a two-hour cross country on a warm, soporific day where nothing happens for the first 90 minutes, and however hard you try to concentrate your mind wanders to the business you're heading for...
then when the engine catches you out the blades will be clapping over your head before you can say goodnight nurse.
PS: Old Bill Barrell, who died of natural causes, once took the rrpm down below 80 percent on me "as a demonstration" and despite his track record and the fact that we were halfway through the FI course I told him I'd refuse to fly with him if he did it again.
then when the engine catches you out the blades will be clapping over your head before you can say goodnight nurse.
PS: Old Bill Barrell, who died of natural causes, once took the rrpm down below 80 percent on me "as a demonstration" and despite his track record and the fact that we were halfway through the FI course I told him I'd refuse to fly with him if he did it again.
OK, How' bout some stats...!
NASA did a detailed study, published in 2000, on acidents between 1963 and 1997 in USA.
Of the 8,436 accidents recorded by the NTSB, 5,371 involved commercially produced single piston helicopters. Now here's the kicker - of those 5,371 accidents, 1,554 or around 30% were attributed to loss of power. Virtually every one of the 1,554 loss of engine power accidents ended in the helicopter being destroyed or substantially damaged.
They say in the narrative: "Therefore, the fact that power-off landing proficiency is not required by the FAA to obtain a helicopter pilot's licence certification appears inconsistent with the number of accidents." They go further to say that "...it also appears that helicopters currently in the civil fleet provide marginal to inadequate autorotational capability for the average pilot to successfully complete the final flare and touchdown to a generally unsuitable site. Clearly, training in full autorotational landings - even to a prepared landing site - is avoided becase of real and perceived risks."
Seems to be pretty strong statistical evidence that pilots are consistently crashing as a result of engine failure. The authors of the study draw the conclusion that the bottom of the auto is entirely to blame, but I would say there must be some accidents in there that were caused by a slow reaction to the engine failure, with the obvious results.
The final quote above is also very interesting, because they seem to be saying that even in the face of obvious evidence that pilots consistently crash at the bottom of an auto, there is resistance to teaching the exercise because of "...real and perceived risks.
SASless, the US did avidly teach touchdown auto's, but during the Vietnam period when many pilots were needed very quickly, they discovered that the acident rate during training was way too high - so they stopped it. I don't however, think that the sausage factory of Vietnam era training applies to the situation now.
By the way; of the 5,371 single piston accidents, 18% involved instruction.
Anyway folks, there are some stats - what do you reckon??
Of the 8,436 accidents recorded by the NTSB, 5,371 involved commercially produced single piston helicopters. Now here's the kicker - of those 5,371 accidents, 1,554 or around 30% were attributed to loss of power. Virtually every one of the 1,554 loss of engine power accidents ended in the helicopter being destroyed or substantially damaged.
They say in the narrative: "Therefore, the fact that power-off landing proficiency is not required by the FAA to obtain a helicopter pilot's licence certification appears inconsistent with the number of accidents." They go further to say that "...it also appears that helicopters currently in the civil fleet provide marginal to inadequate autorotational capability for the average pilot to successfully complete the final flare and touchdown to a generally unsuitable site. Clearly, training in full autorotational landings - even to a prepared landing site - is avoided becase of real and perceived risks."
Seems to be pretty strong statistical evidence that pilots are consistently crashing as a result of engine failure. The authors of the study draw the conclusion that the bottom of the auto is entirely to blame, but I would say there must be some accidents in there that were caused by a slow reaction to the engine failure, with the obvious results.
The final quote above is also very interesting, because they seem to be saying that even in the face of obvious evidence that pilots consistently crash at the bottom of an auto, there is resistance to teaching the exercise because of "...real and perceived risks.
SASless, the US did avidly teach touchdown auto's, but during the Vietnam period when many pilots were needed very quickly, they discovered that the acident rate during training was way too high - so they stopped it. I don't however, think that the sausage factory of Vietnam era training applies to the situation now.
By the way; of the 5,371 single piston accidents, 18% involved instruction.
Anyway folks, there are some stats - what do you reckon??
Join Date: Dec 2002
Location: Lechlade, Glos, UK
Age: 75
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
I think I will continue to avoid the R22!
EOLs should be a regular part of training - 2-3 at the end of every dual trip from the begining. Obviously the early flights will be demos until later in the training. By the time GFTs are in sight the instructor should feel confident in the student's ability and the student should by then have become confident in this exercise so it is no longer a "big deal".
Simulated engine failure should also be practised more than once on every dual trip. Gradually the "surprise" factor should be introduced until the student knows that if his hand is off the collective........
If you do not feel comfortable about EOLs you should not be flying a helicopter and certainly not with pax.
EOLs should be a regular part of training - 2-3 at the end of every dual trip from the begining. Obviously the early flights will be demos until later in the training. By the time GFTs are in sight the instructor should feel confident in the student's ability and the student should by then have become confident in this exercise so it is no longer a "big deal".
Simulated engine failure should also be practised more than once on every dual trip. Gradually the "surprise" factor should be introduced until the student knows that if his hand is off the collective........
If you do not feel comfortable about EOLs you should not be flying a helicopter and certainly not with pax.
Join Date: Sep 2000
Location: UK
Age: 72
Posts: 338
Likes: 0
Received 0 Likes
on
0 Posts
Having spent several years as an ab-initio instructor, I've had experience of some of the more adrenalin raising moments in life, especially on low-inertia rotor types.
The first of these was during a practise engine failure during the climbout. As I started to partially roll the throttle back on the student the engine cut-out completely and we had an exciting moment or two during the 400 feet left between ourselves and the ground. All went well on this occasion but the schools procedure regarding carb heat setting for climbout was adjusted as a consequence.
The second was far more exciting when, during a practise EOL (with the throttle wound back to idle) the student was thrown by some windsheer at low level. As I reached for the cyclic and was about to say those immortal words "I have control" the student flared with such force on the cyclic that he nearly broke my thumb. Unfortunately, he also managed to push the tail rotor straight through the ground culminating in not much of the machine being left in one piece. Neither one of us was hurt, at least not physically.......
Having said all that, I continued for several more years teaching students and ensuring that they conducted many EOLs.
As far as I am concerned, the ability to carry out EOLs succesfully is paramount for any would be helicopter pilot as nothing can better prepare a pilot for the real thing than doing if for real, or at least as real as possible.
As for the training accident...... I would far rather fly with a pilot who has been through some sort of real emergency in his/her formative training than to fly with one who has never had such an experience. Not that I am suggesting that everybody should go out there and smash up a machine during their training!! I just think that going through something for real tends to impart a whole new respect for the dangers of flying.
The first of these was during a practise engine failure during the climbout. As I started to partially roll the throttle back on the student the engine cut-out completely and we had an exciting moment or two during the 400 feet left between ourselves and the ground. All went well on this occasion but the schools procedure regarding carb heat setting for climbout was adjusted as a consequence.
The second was far more exciting when, during a practise EOL (with the throttle wound back to idle) the student was thrown by some windsheer at low level. As I reached for the cyclic and was about to say those immortal words "I have control" the student flared with such force on the cyclic that he nearly broke my thumb. Unfortunately, he also managed to push the tail rotor straight through the ground culminating in not much of the machine being left in one piece. Neither one of us was hurt, at least not physically.......
Having said all that, I continued for several more years teaching students and ensuring that they conducted many EOLs.
As far as I am concerned, the ability to carry out EOLs succesfully is paramount for any would be helicopter pilot as nothing can better prepare a pilot for the real thing than doing if for real, or at least as real as possible.
As for the training accident...... I would far rather fly with a pilot who has been through some sort of real emergency in his/her formative training than to fly with one who has never had such an experience. Not that I am suggesting that everybody should go out there and smash up a machine during their training!! I just think that going through something for real tends to impart a whole new respect for the dangers of flying.
Join Date: May 2001
Location: London
Posts: 528
Likes: 0
Received 0 Likes
on
0 Posts
Squiffy: The NASA study is of limited value unless it differentiates between EOLs where auotorotation was established, and EOLs where it was not.
That's the nub of the matter.
That's the nub of the matter.
There's a very sage article by Derek Jones on R22 training in the latest edition of AOPA's 'General Aviation' magazine. The bottom line for him on EOLs is that they are 'better...demonstrated from an early stage and later practice the relatively simpler gentle single flare to a run-on landing with at least ten knots of wind through the disc.'
AND FINALLY...
At risk of repeating what I've said on other threads before, PLEASE do not try experimenting with anything contrary to limitations or advice in the helicopter Flight Manual. If you deliberately go right to the edge you may fall over. Those of us who do this for a living have been extensively trained to do so and work in a highly risk-managed environment.
AND FINALLY...
At risk of repeating what I've said on other threads before, PLEASE do not try experimenting with anything contrary to limitations or advice in the helicopter Flight Manual. If you deliberately go right to the edge you may fall over. Those of us who do this for a living have been extensively trained to do so and work in a highly risk-managed environment.
Join Date: Oct 2000
Location: U.S.
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
I taught in the U.S. Army sixteen years before the moratorium on touchdown emergency procedures and, subsequent halt of those in all but approved schools. Didn't do TD autos again till I began training civilians.
I will never believe there is any argument or philosophy that replaces the benefit for touchdown autos. We did day straight-in, turning and, low-level (entry alt of 50') autos to the ground. Both hard surface and sod (I prefer sod). We did night straight-in autos to touch down. During the period of time that the "Night Hawk" phase was taught before NVG training, we did night autos with out landing lights.
If EOL training doesn't provide anything else, it provides the confidence that prevents greater than necessary apprehension and, errors comming from that apprehenson.
With out exaggeration, I don't know how many hundreds touchdown autos I've done in H269A's, OH-58's and, UH-1's and, I believe, with out question, that every EOL can be done safely if the instructor will only remember to only do them on the days the conditions will allow (yes, engines quit on bad days but, we have to accept that we can only teach so much), do them to a good surface and, be there for the whole maneuver (if the instructor isn't up to speed for the maneuver or, can't recognize the need to recover when things MIGHT be starting to go bad, he shouldn't be in the maneuver).
Two last points:
The qualification for stopping touchdown emergency procedures training in units was that the accident rate went down dramatically during the moratorium on touchdown emergency procedures training. (Read as: the child birth rate drops dramatically among women who enter convents)
The qualification for teaching EOL's is the rate of unsuccessful completions of actual EOL's as given above.
MY opinions, and happy to have em.
I will never believe there is any argument or philosophy that replaces the benefit for touchdown autos. We did day straight-in, turning and, low-level (entry alt of 50') autos to the ground. Both hard surface and sod (I prefer sod). We did night straight-in autos to touch down. During the period of time that the "Night Hawk" phase was taught before NVG training, we did night autos with out landing lights.
If EOL training doesn't provide anything else, it provides the confidence that prevents greater than necessary apprehension and, errors comming from that apprehenson.
With out exaggeration, I don't know how many hundreds touchdown autos I've done in H269A's, OH-58's and, UH-1's and, I believe, with out question, that every EOL can be done safely if the instructor will only remember to only do them on the days the conditions will allow (yes, engines quit on bad days but, we have to accept that we can only teach so much), do them to a good surface and, be there for the whole maneuver (if the instructor isn't up to speed for the maneuver or, can't recognize the need to recover when things MIGHT be starting to go bad, he shouldn't be in the maneuver).
Two last points:
The qualification for stopping touchdown emergency procedures training in units was that the accident rate went down dramatically during the moratorium on touchdown emergency procedures training. (Read as: the child birth rate drops dramatically among women who enter convents)
The qualification for teaching EOL's is the rate of unsuccessful completions of actual EOL's as given above.
MY opinions, and happy to have em.
What-ho Squiffy wrote:
Yeah? Big deal. What was the fatality rate? Except for the insurance company, who really cares if the aircraft gets destroyed after a loss of power?
Let's not lose focus. The really important figure (the one omitted) is the one that tells us how many people died as a result of those botched autos.
Of the 8,436 accidents recorded by the NTSB, 5,371 involved commercially produced single piston helicopters. Now here's the kicker - of those 5,371 accidents, 1,554 or around 30% were attributed to loss of power. Virtually every one of the 1,554 loss of engine power accidents ended in the helicopter being destroyed or substantially damaged.
Let's not lose focus. The really important figure (the one omitted) is the one that tells us how many people died as a result of those botched autos.
Join Date: Jan 2003
Location: South East England
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
I've been following this thread with great interest and decided as a result, to dust off the old instructor and go for a spot of EOL's to the ground revision. I continuously practice Auto's whenever I fly with suitably qualified passengers, with a recovery on the chosed spot.
The first one was a bit messy with a long ish run on - certainly survivable. The second got better - and after the 8th or 9th I was like an old pro.
I figure that if the entry's OK, and the needles are where thay should be. Providing the flare's put in at the bottom, everyone should walk away, even if the thing rolls.
The hard bit I think, is putting it where you want it to end up.
Moral of the story: "Training is for when things go wrong, and being in a position to put it right"
The first one was a bit messy with a long ish run on - certainly survivable. The second got better - and after the 8th or 9th I was like an old pro.
I figure that if the entry's OK, and the needles are where thay should be. Providing the flare's put in at the bottom, everyone should walk away, even if the thing rolls.
The hard bit I think, is putting it where you want it to end up.
Moral of the story: "Training is for when things go wrong, and being in a position to put it right"
Join Date: Dec 2001
Location: Philadelphia PA
Age: 73
Posts: 1,835
Likes: 0
Received 2 Likes
on
2 Posts
In skid-equipped helicopters, there is a feeling that doing touchdowns on grass or sod is easier on the aircraft than landing on paved, hard surfaces.
Ain't necessarily so.
While it may be quieter, and appear to have a softer landing on grass than on pavement, consider:
a) the skids don't have a chance to flex as the load is transferred from the rotor to the skids - on grass the skids dig a trench and can't move, so the cross tube can only flex in the area between the mounts (Bell series anyway). This eventually leads to failure of the crosstube, but is also evident in those helicopters doing lots of autorotation touchdowns on grass having the tail lower to the ground.
b) if there is any misalignment between the direction you're pointing and the direction of flight, on grass this can cause the helicopter to be aligned pretty forcefully in the direction of flight - a pretty good cause for things like pylon whirl on the 206 series, as the transmission is free to rock from side to side. On paved surfaces you just slide with some misalignment, which can be easily corrected with pedals if you were worried about it.
c) the grass has a pretty high coefficient of friction, and as the skids are well below the CG, this can cause the helicopter to decelerate more quickly than you may wish- and possibly nose over. On paved surfaces, you decelerate rather gently, but with slightly more noise.
d) grass tends to be more uneven, aggrevating c) above.
The only small problem with landings on paved hard surfaces is that you wear out skid shoes more quickly. Get the improved skid shoes (good for several thousand touchdowns) and learn to accept the noise.
The only times I've ever had problems with the touchdown was on grass. There must be a good reason why Bell Helicopter on does touchdowns at their training school on pavement.
Ain't necessarily so.
While it may be quieter, and appear to have a softer landing on grass than on pavement, consider:
a) the skids don't have a chance to flex as the load is transferred from the rotor to the skids - on grass the skids dig a trench and can't move, so the cross tube can only flex in the area between the mounts (Bell series anyway). This eventually leads to failure of the crosstube, but is also evident in those helicopters doing lots of autorotation touchdowns on grass having the tail lower to the ground.
b) if there is any misalignment between the direction you're pointing and the direction of flight, on grass this can cause the helicopter to be aligned pretty forcefully in the direction of flight - a pretty good cause for things like pylon whirl on the 206 series, as the transmission is free to rock from side to side. On paved surfaces you just slide with some misalignment, which can be easily corrected with pedals if you were worried about it.
c) the grass has a pretty high coefficient of friction, and as the skids are well below the CG, this can cause the helicopter to decelerate more quickly than you may wish- and possibly nose over. On paved surfaces, you decelerate rather gently, but with slightly more noise.
d) grass tends to be more uneven, aggrevating c) above.
The only small problem with landings on paved hard surfaces is that you wear out skid shoes more quickly. Get the improved skid shoes (good for several thousand touchdowns) and learn to accept the noise.
The only times I've ever had problems with the touchdown was on grass. There must be a good reason why Bell Helicopter on does touchdowns at their training school on pavement.