Entering autos: discussion split from Glasgow crash thread
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There is a theory....
I am exactly talking about what happens with controls locked. That's what the whole post was about. Its theoretical. If you haven't as you've stated done something about it you are dead! And yes the nose does drop when the pilot drops the collective. Its like the demo on flapback and inflow roll you get when first doing basic transitions - nice for a demo but the pilot (hopefully) instantly compensates and it becomes something the instructors scribble about on a board.
And turns out my explanation is remarkably close to the one in FTM 107 - Google it. Chapter 10 is the one you want.
As for not passing it on to students, it all depends on the student. Sure, not a basic guy, but its a worthy discussion point on a black weather day. I am in no way advocating any technique based on the fact the nose might pitch up a tiny amount on engine failure. The yaw will be the dominant factor.
Great to hear the war stories. All my experience is from practice engine failures to determine the avoid curve and maximum pilot intervention delay time so hearing real stuff is great. Had plenty of single fails though - perhaps you should go to a nice reliable twin or triple.
Cheers GM
And turns out my explanation is remarkably close to the one in FTM 107 - Google it. Chapter 10 is the one you want.
As for not passing it on to students, it all depends on the student. Sure, not a basic guy, but its a worthy discussion point on a black weather day. I am in no way advocating any technique based on the fact the nose might pitch up a tiny amount on engine failure. The yaw will be the dominant factor.
Great to hear the war stories. All my experience is from practice engine failures to determine the avoid curve and maximum pilot intervention delay time so hearing real stuff is great. Had plenty of single fails though - perhaps you should go to a nice reliable twin or triple.
Cheers GM
Last edited by GipsyMagpie; 19th Dec 2013 at 03:42. Reason: typo
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I recall our fixed wing brethren have a description for how one shoves the stick, from memory I think they refer to it as flying through either feel or flying through displacement. With all beginners it's displacement then as they build experience they (or most of them at least) learn the feel, and the flying bit becomes second nature.
A rotary wing example of this was when I was learning the hovering autos in the low inertia rotor r22. Instructor chops the throttle and up goes the lever - control displacement pure and simple. I have no recollection of where the cyclic was shoved as I just wanted the skids to land flat. Then I moved to the high inertia rotor B206. Instructor chops throttle and up goes the lever and up went the JetBanger
. But I was onto it quickly and beat my instructor in pushing the collective back down then pulling it back up again in a more sympathetic way relative to our rate of decent. I think my instructor was suitably impressed, I even had the nose yaw pinned on its heading without much thinking about it.
Not a terribly exciting story I know but one that does show the development mode of learning to fly under supervision. Autorotation is a stable mode of flight that one should be able to transition into automatically and easily after a loss of engine power, so that when one looks up and sees that one is about to park the machine in a big dead tree looming up ahead one may have brought themselves that extra few seconds of flying around it. We may learn this maneuver through displacement technique first, but after we get the hang of it and explore the envelope under supervision, we should find that moving into the stable flight mode of autorotation becomes second nature.
Having said all that, I know some fixed wingers, albeit low timers, that never mastered flying by feel and probably never will. Yes they are capable of flying to an acceptable standard, but they tend to work harder at it than most to achieve a rather ordinary outcome.
A rotary wing example of this was when I was learning the hovering autos in the low inertia rotor r22. Instructor chops the throttle and up goes the lever - control displacement pure and simple. I have no recollection of where the cyclic was shoved as I just wanted the skids to land flat. Then I moved to the high inertia rotor B206. Instructor chops throttle and up goes the lever and up went the JetBanger
. But I was onto it quickly and beat my instructor in pushing the collective back down then pulling it back up again in a more sympathetic way relative to our rate of decent. I think my instructor was suitably impressed, I even had the nose yaw pinned on its heading without much thinking about it. Not a terribly exciting story I know but one that does show the development mode of learning to fly under supervision. Autorotation is a stable mode of flight that one should be able to transition into automatically and easily after a loss of engine power, so that when one looks up and sees that one is about to park the machine in a big dead tree looming up ahead one may have brought themselves that extra few seconds of flying around it. We may learn this maneuver through displacement technique first, but after we get the hang of it and explore the envelope under supervision, we should find that moving into the stable flight mode of autorotation becomes second nature.
Having said all that, I know some fixed wingers, albeit low timers, that never mastered flying by feel and probably never will. Yes they are capable of flying to an acceptable standard, but they tend to work harder at it than most to achieve a rather ordinary outcome.
Newfie.....
You brought me out before the 14 pages were up....
How ya been? You gonna make it home for Christmas this year? Hope so... Hopefully I head home on Friday.....Happy holidays and all that crap, & Say hi to your lovely wife. Have just found out tis cheaper to fly to Cyprus than the UK, not that I really wanted to visit the UK but oh well ---ya in?
Oh and to keep it relevant...... I too have my "cunning plan"... (although to be honest, mine is all about IIMC---never really had to think about the plan for engine failure....it just came natural like), anyways, best advice to any student.....you better have one.... Whether it is down or aft first---who cares, just have a plan.
You brought me out before the 14 pages were up....
How ya been? You gonna make it home for Christmas this year? Hope so... Hopefully I head home on Friday.....Happy holidays and all that crap, & Say hi to your lovely wife. Have just found out tis cheaper to fly to Cyprus than the UK, not that I really wanted to visit the UK but oh well ---ya in?
Oh and to keep it relevant...... I too have my "cunning plan"... (although to be honest, mine is all about IIMC---never really had to think about the plan for engine failure....it just came natural like), anyways, best advice to any student.....you better have one.... Whether it is down or aft first---who cares, just have a plan.
Gordy says:
Well I guess for the 2011 "Mosby" pilot (the texting EMS guy), his plan didn't come "natural like." Either he didn't have a plan at all or he messed up the plan he did have. And since he was a 2500 hour, military-trained pilot...it makes you wonder, doesn't it?
If you're cool with bottoming the lever first and starting an immediate descent upon engine failure, hey that's fine by me. Because maybe in your limited way of thinking the descent is inevitable anyway, so why not start now?
But me, I'd rather get the nose up first and hold altitude (if I can) while searching for a place to put it down. Getting the nose up buys precious seconds, especially when I'm bopping along at well above best-auto speed.
Engine failures don't always happen in the training environment at 80 knots with good forced-landing areas in reach.
I know that all of the helicopters I've flown will benefit from "cyclic-back" first in cruise. Now don't be stupid. Don't be dense. Don't assume that I mean you can bring the cyclic back and...la-la-la...do nothing else. OF COURSE the collective needs to go down now! Of course. Nobody is disputing that. But the instinctive priority should be on getting the nose up while you get your hand back on the collective and start pushing it down. While you're doing these things (without looking at the controls) you can be looking for a place to set down. In my last job my flights were frequently 1.5 to 2.0 hours long in stabilized cruise. No way am I going to sit there with my hand on the collective the whole time. No thank you, my left hand will be on my knee, just inches and microseconds from the control.
The "Mosby" pilot was down to around 300' agl at 116 kts GS when his engine quit. And then, according to the NTSB, five seconds later the helicopter hit the ground at a...
A 40 degree angle. Huh? How could that happen? I'm sure his "plan" was to bottom the pitch, which, is probably exactly what he did...first. I mean, do we think he was incompetent? Do we assume that he did nothing? That he froze on the controls? Not me. I believe he at least bottomed the collective as we all would. After all, he was worried that it would quit...expected it to quit. And still F'ed it up. Why? Let's let the NTSB fill in some blanks.
Oh snap! Talk about the NTSB "dissing" the FAA! Wow. Because that's what's important here: The ENTRY into autorotation. Did you notice how the NTSB put "aft cyclic" first in their description of the entry into an auto for the AS350? Even the NTSB concedes that bottoming the pitch isn't the solution; it must be accompanied by a simultaneous aft cyclic input. How much and how fast you make that input will depend on how low you are and whether you have a forced-landing area all picked out. So there you have it, straight from the horse's (NTSB's) mouth: Collective-first is wrong.
In our hero brains we all assume that we'll respond expertly and correctly to every emergency God can throw at us. "Mosby" proved otherwise. Because - from cruise speed, anyway - the urge to bottom the collective first is the wrong one. Yes, it's what we've all been taught since our first days of dual in that helicopter that auto'd at the same speed it cruised at, or in the training scenario where the engine was pulled at 80 knots in the traffic pattern. But in reality...out in the real world, in aircraft that cruise along at a speed much higher than best-auto, the instinctive reaction should be to get the nose/tip path plane up first, and then get the pitch going down. That's my plan.
Will other plans work? Sure, obviously, if you have the time and altitude to get into a stabilized auto before you start running out of options. But if you don't...?
I too have my "cunning plan"... (although to be honest, mine is all about IIMC---never really had to think about the plan for engine failure....it just came natural like)
If you're cool with bottoming the lever first and starting an immediate descent upon engine failure, hey that's fine by me. Because maybe in your limited way of thinking the descent is inevitable anyway, so why not start now?
But me, I'd rather get the nose up first and hold altitude (if I can) while searching for a place to put it down. Getting the nose up buys precious seconds, especially when I'm bopping along at well above best-auto speed.
Engine failures don't always happen in the training environment at 80 knots with good forced-landing areas in reach.
I know that all of the helicopters I've flown will benefit from "cyclic-back" first in cruise. Now don't be stupid. Don't be dense. Don't assume that I mean you can bring the cyclic back and...la-la-la...do nothing else. OF COURSE the collective needs to go down now! Of course. Nobody is disputing that. But the instinctive priority should be on getting the nose up while you get your hand back on the collective and start pushing it down. While you're doing these things (without looking at the controls) you can be looking for a place to set down. In my last job my flights were frequently 1.5 to 2.0 hours long in stabilized cruise. No way am I going to sit there with my hand on the collective the whole time. No thank you, my left hand will be on my knee, just inches and microseconds from the control.
The "Mosby" pilot was down to around 300' agl at 116 kts GS when his engine quit. And then, according to the NTSB, five seconds later the helicopter hit the ground at a...
a 40° nose-down attitude at a high rate of descent with a low rotor rpm.
The simulator flight tests conducted after this accident showed that when a loss of engine power occurs in the Eurocopter AS350 B2 at cruise airspeeds, the pilot must simultaneously apply aft cyclic and down collective in order to maintain rotor rpm and execute a successful autorotation. However, the pilot’s autorotation training was done at airspeeds below cruise where less aft cyclic is needed to enter an autorotation. Further, FAA guidance on performing autorotations stresses lowering the collective as the initial step in entering an autorotation, does not emphasize the importance of other flight control inputs, and provides minimal information on the critical entry phase of autorotation.
In our hero brains we all assume that we'll respond expertly and correctly to every emergency God can throw at us. "Mosby" proved otherwise. Because - from cruise speed, anyway - the urge to bottom the collective first is the wrong one. Yes, it's what we've all been taught since our first days of dual in that helicopter that auto'd at the same speed it cruised at, or in the training scenario where the engine was pulled at 80 knots in the traffic pattern. But in reality...out in the real world, in aircraft that cruise along at a speed much higher than best-auto, the instinctive reaction should be to get the nose/tip path plane up first, and then get the pitch going down. That's my plan.
Will other plans work? Sure, obviously, if you have the time and altitude to get into a stabilized auto before you start running out of options. But if you don't...?
"Just a pilot"
Engine failures? 2 in 11,500 hrs
1, on the ground after rolling back to ground idle
1, a Twinstar in flight
Add 1 power train failure in a H 269B
1, a Twinstar in flight
Add 1 power train failure in a H 269B
"Just a pilot"
The Mosby accident FH1100 mentions is startling, especially the final 5 seconds- quoting from the NTSB report
http://www.ntsb.gov/doclib/reports/2013/AAR1302.pdf:
"The pilot’s awareness of the helicopter’s low fuel status and the near zero indication on the fuel gauge as the flight continued should have given the pilot ample warning of the impending engine failure and provided him with the opportunity to prepare to execute an autorotation. However, it was evident from the helicopter’s impact in a 40° nose-down attitude, on a heading nearly opposite to the direction of travel, at a high rate of descent, and with a low rotor rpm that the pilot did not successfully execute an autorotation following the loss of engine power."
http://www.ntsb.gov/doclib/reports/2013/AAR1302.pdf:
"The pilot’s awareness of the helicopter’s low fuel status and the near zero indication on the fuel gauge as the flight continued should have given the pilot ample warning of the impending engine failure and provided him with the opportunity to prepare to execute an autorotation. However, it was evident from the helicopter’s impact in a 40° nose-down attitude, on a heading nearly opposite to the direction of travel, at a high rate of descent, and with a low rotor rpm that the pilot did not successfully execute an autorotation following the loss of engine power."
Last edited by Devil 49; 19th Dec 2013 at 15:17. Reason: spelling error
I don't think those words mean what you think they mean.
That's funny, I read the same report and did not find them saying that.
Let's peak at what they actually wrote, and what you excerpted from the report:
They identify the case as "at cruise speed." They identify his training as not covering the loss of power at cruise speed. That's a systemic error, or "supervisory error" as we used to call it in the Navy when we investigated mishaps. To a certain extent, you can argue that by that lack in his training he was set up ... if you want to so argue. But shouldn't a professional pilot know about how that works and should work? I'll argue that a professional pilot should, and I hope you'll agree with me.
The key takeaway is that he was a 116 knots, which I gather is higher than "best" autorotation speed.
When he lost the engines he did not transition to best auto speed as he lowered the collective, which you do have to do. Funny, the NTSB concurs with me, on the simultaneity of how that happens. As before, helicopter pilots fly with both hand, and helicopter pilots multi task. If you don't or can't, fly something else.
As to your analysis, it is misleading to taking these control inputs in isolation. That isn't how helicopter flying is done. The controls work together.
Other than that little carping, I think you made some good points in your post. I completely agree with you that he either had no plan, or the plan he had was badly executed.
That's funny, I read the same report and did not find them saying that.
Let's peak at what they actually wrote, and what you excerpted from the report:
the pilot must simultaneously apply aft cyclic and down collective in order to maintain rotor rpm and execute a successful autorotation.
However, the pilot’s autorotation training was done at airspeeds below cruise where less aft cyclic is needed to enter an autorotation.
However, the pilot’s autorotation training was done at airspeeds below cruise where less aft cyclic is needed to enter an autorotation.
The key takeaway is that he was a 116 knots, which I gather is higher than "best" autorotation speed.
When he lost the engines he did not transition to best auto speed as he lowered the collective, which you do have to do. Funny, the NTSB concurs with me, on the simultaneity of how that happens. As before, helicopter pilots fly with both hand, and helicopter pilots multi task. If you don't or can't, fly something else.
As to your analysis, it is misleading to taking these control inputs in isolation. That isn't how helicopter flying is done. The controls work together.
Other than that little carping, I think you made some good points in your post. I completely agree with you that he either had no plan, or the plan he had was badly executed.
I have to say that I am gob smacked that so many professional pilots seemed to have been trained so badly and or their opc's are done without an auto from a cruise speed 
Or am I missing something ? it is bleeding obvious that you have to apply aft cylic ( from a fast cruise)as the lever goes down otherwise you are in a very uncomfortable nose down attitude. Which will then require a massive amount of collective as you load the disc to recover attitude with cylic.
Again have I missed something here ?
Or am I missing something ? it is bleeding obvious that you have to apply aft cylic ( from a fast cruise)as the lever goes down otherwise you are in a very uncomfortable nose down attitude. Which will then require a massive amount of collective as you load the disc to recover attitude with cylic.Again have I missed something here ?
But Lonewolf, look at the way the NTSB wrote it. Yes, they said "simultaneously," but then they put "aft cyclic" first before saying "down collective." I, for one, find the wording of that phrase curious. It's like they know that during the autorotation entry, the aft cyclic input is as important, if not more so, than lowering the collective. But who knows.
And Hughes, you're not missing something. We've heard over and over in this thread from people who claim that the first response to an engine failure is "LOWER COLLECTIVE!!" with a kind of "oh yeah" addition of "maintain attitude" as if the latter part isn't as important as the prior. And that's fine...up at altitude where there's plenty of time to sort things out. But we don't always have the luxury of time. The "Mosby" pilot didn't.
I think there are three reasonable scenarios for the "Mosby" crash.
1. When the engine quit, the pilot uttered either one or two or three four-letter words as he rapidly dumped the collective, just as he was trained to do and just as Thomas Coupling suggests. This probably bunted him over into a 40 - 50 degree nose-down attitude. In the remaining three of the five seconds left in the flight, I'd bet that he had the cyclic back in his gut, but it was largely ineffective and only got the nose back up to 40 degrees before impact.
2. When the engine quit, maybe the pilot did actually panic and freeze, and did nothing with the controls for the remaining five seconds which probably seemed very short to him. Hey, I've seen it happen! Pilots freeze up! And it would explain why the ship impacted the ground on a reverse heading to the initial. If he did nothing to any of the controls, tail rotor thrust would've yawed the thing around as it plummeted to the ground at a 40-45 degree angle.
3. When the engine quit, he knew he was boned and that it was all going to come out...the lack of preflight, the poor planning, the texting with his girlfriend...the girlfriend herself (and wouldn't his wife be surprised to hear about that!). So maybe he just said, "Goodbye, cruel world!" and rode 'er in with a feeling of intense resignation and despair.
I don't know. I *do* know that if he merely dumped the collective first, as so many here seem to suggest, then he sealed his own fate.
And Hughes, you're not missing something. We've heard over and over in this thread from people who claim that the first response to an engine failure is "LOWER COLLECTIVE!!" with a kind of "oh yeah" addition of "maintain attitude" as if the latter part isn't as important as the prior. And that's fine...up at altitude where there's plenty of time to sort things out. But we don't always have the luxury of time. The "Mosby" pilot didn't.
I think there are three reasonable scenarios for the "Mosby" crash.
1. When the engine quit, the pilot uttered either one or two or three four-letter words as he rapidly dumped the collective, just as he was trained to do and just as Thomas Coupling suggests. This probably bunted him over into a 40 - 50 degree nose-down attitude. In the remaining three of the five seconds left in the flight, I'd bet that he had the cyclic back in his gut, but it was largely ineffective and only got the nose back up to 40 degrees before impact.
2. When the engine quit, maybe the pilot did actually panic and freeze, and did nothing with the controls for the remaining five seconds which probably seemed very short to him. Hey, I've seen it happen! Pilots freeze up! And it would explain why the ship impacted the ground on a reverse heading to the initial. If he did nothing to any of the controls, tail rotor thrust would've yawed the thing around as it plummeted to the ground at a 40-45 degree angle.
3. When the engine quit, he knew he was boned and that it was all going to come out...the lack of preflight, the poor planning, the texting with his girlfriend...the girlfriend herself (and wouldn't his wife be surprised to hear about that!). So maybe he just said, "Goodbye, cruel world!" and rode 'er in with a feeling of intense resignation and despair.
I don't know. I *do* know that if he merely dumped the collective first, as so many here seem to suggest, then he sealed his own fate.
But Lonewolf, look at the way the NTSB wrote it. Yes, they said "simultaneously," but then they put "aft cyclic" first before saying
"down collective." I, for one, find the wording of that phrase curious. It's
like they know that during the autorotation entry, the aft cyclic input
is as important, if not more so, than lowering the collective. But who knows.
"down collective." I, for one, find the wording of that phrase curious. It's
like they know that during the autorotation entry, the aft cyclic input
is as important, if not more so, than lowering the collective. But who knows.
And Hughes, you're not missing something. We've heard over and over in this thread from people who claim that the first response to an engine failure is "LOWER COLLECTIVE!!" with a kind of "oh yeah" addition of "maintain attitude" as if the latter part isn't as important as the prior.
But we don't always have the luxury of time.
1. When the engine quit, the pilot uttered either one or two or three four-letter words as he rapidly dumped the collective, just as he was trained to do and just as Thomas Coupling suggests. This probably bunted him over into a 40 - 50 degree nose-down attitude.
2. When the engine quit, maybe the pilot did actually panic and freeze, and did nothing with the controls for the remaining five seconds which probably seemed very short to him. Hey, I've seen it happen!
3. When the engine quit, he knew he was boned and that it was all going to come out...the lack of preflight, the poor planning, the texting with his girlfriend...the girlfriend herself (and wouldn't his wife be surprised to hear about that!). So maybe he just said, "Goodbye, cruel world!" and rode 'er in with a feeling of intense resignation and despair.
I don't know. I *do* know that if he merely dumped the collective first, as so many here seem to suggest, then he sealed his own fate.
The energy management concept certainly seems the better framework for teaching about this facet of helicopter flying.
Cheers.
The pilot must simultaneously apply aft cyclic and down collective in order to maintain rotor rpm and execute a successful autorotation.
However, the pilot’s autorotation training was done at airspeeds below cruise where less aft cyclic is needed to enter an autorotation.
However, the pilot’s autorotation training was done at airspeeds below cruise where less aft cyclic is needed to enter an autorotation.
Since you are all very challenged re sentence construction and the elements of Grammar that means you are quite wrong and need to pay attention.
Simultaneously......is defined to mean "At the same time".....the usage of the phrase "Aft Cyclic AND Down Collective" is not order specific. Either way it could be written with the words Collective or Cyclic in either sequence means nothing other than the one set of words has to be written before the other.....and that is all the hell it means.
The use of the word "less" connotes Aft Cyclic was required.....but not as much as in a high speed cruise situation.
Jesus Guys.....quit twisting what was written to try to buttress your argument.
This is getting silly.
DB.....as you know some folks at EC due to your 225 experience and background in the past.....how about asking them to replicate the Mosby Crash Scenario for you....and report back what they find out?
I would really like to know if only lowering the Collective while in a level Cruise at 116 Knots in a 350 during an entry into Autorotation and not moving the Cyclic will result in a 40 degree or more Dive.....it cannot be that complicated to find out!
Likewise.....how does one accomplish a 180 degree turn at the same time and ...and lose Rotor RPM....as it is going to be a steep turn from 300 feet in a screaming ass dive where one would assume there would be some G Loading on the Head that would tend to build RPM.....something you all insist G Loading shall do?
Any 350 Drivers willing to try......Devil 49....you fly those EC things.....what you think?
Lonewolf:
Boy, you hit the nail right on the head here. Instead of robotically lowering the collective at the point of engine failure, it's far more important to be concerned with energy management.
In cruise flight, a helicopter rotor has an enormous amount of energy stored in it. It would be a crime to let it go to waste. Sure, lowering the collective is of paramount importance, but that's not the FIRST thing you should consider doing - because that act will waste precious energy and time. In the first place, it will start a descent. Hey, you might not want to descend right away! Using that stored energy in the rotor to maintain level flight - even for just a few seconds - seems pretty dang important to me.
And you can't just "maintain attitude" either. Most helicopter cruise at a slightly nose-down cabin attitude, and a more pronounced "nose-down" attitude of the disk. So at the point of engine failure the disk *has* to be brought up to level, at least!...OR you're going to descend immediately. With the forward tilt of the mast in modern helicopters, that means the pilot would have to select a positive cabin attitude of around 5 degrees (more in an S-76) just to keep the disk level. But you want to do more than that. You want to get the airflow reversed from "down through the disk" to "upward through the disk." This will...eventually...happen automatically as the helicopter descends and the autorotation stabilizes, but you'll be using up precious altitude to do it...altitude you may not have if you're like many, many helicopter pilots I know who routinely cruise at 1,000' agl or less.
If you are cruising along at 500' agl with the wind behind you when the engine quits in your AS350 and you immediately bottom the pitch first, I guarantee that you'll probably not be able to get it sorted out and get the ship turned around into the wind in time for a landing. You'll probably just land straight ahead. If you do it right, you might not land at a 40 degree nose-down attitude. But if you insist that lowering the collective first is the proper way to enter an auto (especially in an AS350) you just might.
The energy management concept certainly seems the better framework for teaching about this facet of helicopter flying.
In cruise flight, a helicopter rotor has an enormous amount of energy stored in it. It would be a crime to let it go to waste. Sure, lowering the collective is of paramount importance, but that's not the FIRST thing you should consider doing - because that act will waste precious energy and time. In the first place, it will start a descent. Hey, you might not want to descend right away! Using that stored energy in the rotor to maintain level flight - even for just a few seconds - seems pretty dang important to me.
And you can't just "maintain attitude" either. Most helicopter cruise at a slightly nose-down cabin attitude, and a more pronounced "nose-down" attitude of the disk. So at the point of engine failure the disk *has* to be brought up to level, at least!...OR you're going to descend immediately. With the forward tilt of the mast in modern helicopters, that means the pilot would have to select a positive cabin attitude of around 5 degrees (more in an S-76) just to keep the disk level. But you want to do more than that. You want to get the airflow reversed from "down through the disk" to "upward through the disk." This will...eventually...happen automatically as the helicopter descends and the autorotation stabilizes, but you'll be using up precious altitude to do it...altitude you may not have if you're like many, many helicopter pilots I know who routinely cruise at 1,000' agl or less.
If you are cruising along at 500' agl with the wind behind you when the engine quits in your AS350 and you immediately bottom the pitch first, I guarantee that you'll probably not be able to get it sorted out and get the ship turned around into the wind in time for a landing. You'll probably just land straight ahead. If you do it right, you might not land at a 40 degree nose-down attitude. But if you insist that lowering the collective first is the proper way to enter an auto (especially in an AS350) you just might.
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I do not want to be dick but......surely most competent, well co-ordinated pilots would "Simultaneously" move both controls and the pedals for that matter. Is that not the fundamental principle we all learnt right at the beginning. You cannot move one control without having to move the two others!!
That's why we can pat our belly and rub our head (or some such) at the same time.
I do think however, that slamming the lever down at high speed will initiate, and lead to, a strong nose tuck for some types. Maybe this is what happened in the Moseby accident. Paradoxically, knowing he was short of fuel, he my have slammed the lever to the floor and just failed to prevent the nose tuck and the subsequent loss of control it leads to.
SAS - sorry just saw the end f your post. I have about 3k on 355s (of course two engines) but the fuselage is essentially the same shape. The nose definitely drops if the lever is lowered aggressively and I think this is similar to most types but most of us make a "joined up" control movement instinctively and the tendency is overcome without us seeing it through to its full manifestation.
Same as Flapback and inflow roll during take off run. How many of us, not doing basic instruction, actually recognise this anymore. It's become a subconscious set of contro movements in response to attitude.
DB
That's why we can pat our belly and rub our head (or some such) at the same time.
I do think however, that slamming the lever down at high speed will initiate, and lead to, a strong nose tuck for some types. Maybe this is what happened in the Moseby accident. Paradoxically, knowing he was short of fuel, he my have slammed the lever to the floor and just failed to prevent the nose tuck and the subsequent loss of control it leads to.
SAS - sorry just saw the end f your post. I have about 3k on 355s (of course two engines) but the fuselage is essentially the same shape. The nose definitely drops if the lever is lowered aggressively and I think this is similar to most types but most of us make a "joined up" control movement instinctively and the tendency is overcome without us seeing it through to its full manifestation.
Same as Flapback and inflow roll during take off run. How many of us, not doing basic instruction, actually recognise this anymore. It's become a subconscious set of contro movements in response to attitude.
DB
SASless:
I think that's very presumptuous of you. The NTSB reports are not thrown together as haphazardly as some people post on PPRUNE. They're carefully thought-out and worded. The fact is, they didn't put the "lower collective" item first. So nobody, least of all the great and wonderful, all-knowing SASless can infer or imagine or fantasize what they meant by writing it the other way 'round. (See, Bob? That's why nobody likes you! You have absolutely no respect for any of the egotistical, self-important blowhards on forums like these.)
In any event, it's true that a coordinated, simultaneous lowering of the collective and making an aft cyclic input would not hurt. But neither would making the aft cyclic input first. And in fact there are some obvious benefits to doing so, as I've stated. Had the "Mosby" pilot listened to the preachings of good Brother Gillies, he and his crew might not be dead now. I know, I know...pure speculation. But let the record show that, *if* he put the pitch down at all, the aircraft ended up lawn-darting at 40 degrees nose down. OUCH!
For the record, the "Mosby" Astar was not in level cruise when his engine quit; he was in a shallow descent. He stayed pretty much at 600' agl during the 30 minute flight, but as he neared the airport, being obviously over-anxious and stressed-out he began a premature descent and was only at 250-300' agl while still more than a mile from the field boundary when it quit on him. So...what...maybe another degree or two nose-down?
The other thing is that the NTSB did a lot of research about AS350 autorotational qualities in the sim. We all know that as good as sims are, they do not and cannot replicated every flight regime with complete accuracy. There may be aspects of the very weird dynamics of an engine failure at high speed cruise-descent that the sim "misses" or just synthesizes differently from the real aircraft.
Simultaneously......is defined to mean "At the same time".....the usage of the phrase "Aft Cyclic AND Down Collective" is not order specific. Either way it could be written with the words Collective or Cyclic in either sequence means nothing other than the one set of words has to be written before the other.....and that is all the hell it means.
In any event, it's true that a coordinated, simultaneous lowering of the collective and making an aft cyclic input would not hurt. But neither would making the aft cyclic input first. And in fact there are some obvious benefits to doing so, as I've stated. Had the "Mosby" pilot listened to the preachings of good Brother Gillies, he and his crew might not be dead now. I know, I know...pure speculation. But let the record show that, *if* he put the pitch down at all, the aircraft ended up lawn-darting at 40 degrees nose down. OUCH!
For the record, the "Mosby" Astar was not in level cruise when his engine quit; he was in a shallow descent. He stayed pretty much at 600' agl during the 30 minute flight, but as he neared the airport, being obviously over-anxious and stressed-out he began a premature descent and was only at 250-300' agl while still more than a mile from the field boundary when it quit on him. So...what...maybe another degree or two nose-down?
The other thing is that the NTSB did a lot of research about AS350 autorotational qualities in the sim. We all know that as good as sims are, they do not and cannot replicated every flight regime with complete accuracy. There may be aspects of the very weird dynamics of an engine failure at high speed cruise-descent that the sim "misses" or just synthesizes differently from the real aircraft.
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I been thinking to myself, "self I must read this thread thru and contribute something, seeing as how that low level is where I have lived for the last forty years and check and training of survival in the small survivable areas of it is second nature to me, and many have come back and thanked me for getting them out of the poo at times".
I would like to keep it simple. At the end of it all I encourage people to think why it is not a good idea to be in an impossible to do a safe auto area, say hovering at 80 feet. They simply must come away from these exercises thinking how they will change their mustering or LL techniques when between 20 and 250 feet to always involve a safe airspeed.
1. As Nick Lappos says discussions and training in these aspects encourage us the think. The Robinson safety course is an excellent example in stimulating thinking in their explanation of energy management during autorotation; I assume other factory courses to be the same.
Thought process one, all helicopters are designed and tested for certification to sustain the inactivity of a brainless pilot for at least a second without further control adjustment once the power source becomes silent, one doesn't need to be violent. So entry is to position the A/C in a good auto flight or termination mode and you will drop quite a-ways doing that if starting from a low or zero airspeed.
Thought process two, my ab-initio instructor (ex Brit army) encouraged me to think along these lines. "There may be any number of reasons why you have to quickly enter autorotation. Upon noticing that things are not right you are to firstly, rationalise the problem - solve with your solution - then ACT. Because you're a blasted country bumpkin I'll give a full quarter of a second to start acting, any more and I'll thump you, which he would." A later debrief would explore my thought processes and actions.
2. Of the very many emergencies I have experienced all bar one were at LL and thanks to my ex Brit army mate I always had a spot in sight, it’s amazing what you will fit into at times.
Thought process three, always but always pick spots and plan your approaches to them as you are tooling along.
3. During my early check and training experience, in fact when I was getting checked out to conduct C&T having by then done a bit of it by one CASA man (or whatever the fed agency was called then) Holga Von (something long name, ex Oz army), he says to me. "You seem to be teaching autos at cruise speed 8 feet, 50 feet or 500 feet, or hovering autos at 300 feet, why not is it that you do not teach them at 40 knots and 250 feet where you seem to operate mostly all day?"
Thought process four, Jawohl! We quickly found some error inducement in pilots doing autos at 250 feet had they been conditioned to do them at 50 feet say and at high cruise settings. That error was to fairly quickly bring the cyclic back thus leaving one with no airspeed at a most uncomfortable height. (Not enough thought process)
There seem to me to be four parts of an auto; 1, entry, 2, decent during auto (range chasing if needed) 3, the termination area - say one knot of airspeed must equal one foot of height 50 /50 is nice where one begins to flare, then 4, the touchdown. It matters not how far one will fly in descent if at all, the main game is to arrive at a nice 'termination area', and the rest should follow. A good entry will easily facilitate this and it is where this discussion started so that brings me to what I do now which is to check out several regimes of our LL practices.
a) Fast cruise at super low level where one will bring a whole lot of pain if the cyclic is brought back too early and slams the T/R into something solid beneath, one first must give the collective a quick flick up, then down again as a small cyclic zoom climb is performed as part of a quick stop technique to arrive comfortably in the 'termination area'
b) More than 50 knots at say 50 feet where one simply enters a quick stop routine, collective going down smoothly as the cyclic aft is being applied to arrive at the same height and now established in the 'termination area'. Less than 50 knots down to say 25 knots, leave the A/S where it is until you intercept a 'termination area' further down, but that collective must be got down smartly.
c) At 50 to 250 feet and between thirty and seventy knots, under no circumstances do I want to see a quick check back on cyclic, cos it may hurt you when I thump you and me if it turns real and you have run us right out of airspeed in that nasty height area.
d) Normal cruising at a higher height as between 40 knots and above, checking back on cyclic is not necessary as it may condition you to a bad mistake in tighter circumstances, refer point 1 para 2.
e) Very slow A/S or hover at LL. This procedure is checked at 300 feet after demonstration and follow thru, and at lower heights it is demonstrated only with power recovery and always positioned to reach a target spot. Here I use the point process. Point everything you got brother at your spot, collective, cyclic and right pedal. The RRPM will not decay too much and can be easily got back in hand after about 80 to 120 feet which is where the A/S will again be approaching 60 knots. Do not check back on cyclic until the aircraft is pointed downwards, then I will calmly say, “60 knots attitude please - not 600”, it is then quite a large check back. First couple of demos as hands off I ask them to strongly monitor both the RRPM and A/S. it only takes a second to get down that first bit with the cyclic forward and the RRPM will be still be in the green.
I often use the analogy of the F/W being a bit high on finals; one can simply quickly dive off the extra altitude without increase of speed to arrive a nicer height, so too do we dive off height with the point process to arrive at a safe 'termination area' with enough inertia still in our M/R. You may even be lucky enough to have picked up a small extra airspeed which can be flared off to help arrest ROD. In all slow entries either maintain or increase your A/S if possible. I.E. Do not check back on cyclic at entry.
In all instances I talk a lot about ROD being at the very minimum you can achieve at ground level as high ROD is what will kill you.
It is incredibly important that the auto RRPM must be set up as the Manufacturer describes in the manual. If it is too high ground the A/C as it is too easy to slam the collective down and increase the ROD too much, and I have the back to prove it.
There are four items that need to be completed and checked when an entry to auto is required; 1. collective down RRPM in the green, 1. Set the A/C attitude for max range A/S or the desired A/S under the circumstances, 1. Safe to reach a spot or already turning into wind. 1. Get a mayday out.
Note the generic priority, one doesn’t need to psyche oneself to think about a mayday, just hold the blessed xmit button down while you are briefing others or whatever. Any person listening to a radio is an attentive person, they will do something to help.
Autos from higher heights can induce errors in a pilot's range assessment if auto flight is continued after joining needles. The glide path then changes, so when joining needles at say 300 feet fly away and look away.
Please fly a little higher and a little faster if possible and no passengers while doing Air-work.
None of the above is a recipe for survival or designed as a pissing contest from a predicted height A/S combination say, as every A/C and day is different. It is amazing how easy it is on a very cool, windy day and, lightly loaded compared with a muggy, hot day with a heavy A/C.
MERRY XMAS tet.
I would like to keep it simple. At the end of it all I encourage people to think why it is not a good idea to be in an impossible to do a safe auto area, say hovering at 80 feet. They simply must come away from these exercises thinking how they will change their mustering or LL techniques when between 20 and 250 feet to always involve a safe airspeed.
1. As Nick Lappos says discussions and training in these aspects encourage us the think. The Robinson safety course is an excellent example in stimulating thinking in their explanation of energy management during autorotation; I assume other factory courses to be the same.
Thought process one, all helicopters are designed and tested for certification to sustain the inactivity of a brainless pilot for at least a second without further control adjustment once the power source becomes silent, one doesn't need to be violent. So entry is to position the A/C in a good auto flight or termination mode and you will drop quite a-ways doing that if starting from a low or zero airspeed.
Thought process two, my ab-initio instructor (ex Brit army) encouraged me to think along these lines. "There may be any number of reasons why you have to quickly enter autorotation. Upon noticing that things are not right you are to firstly, rationalise the problem - solve with your solution - then ACT. Because you're a blasted country bumpkin I'll give a full quarter of a second to start acting, any more and I'll thump you, which he would." A later debrief would explore my thought processes and actions.
2. Of the very many emergencies I have experienced all bar one were at LL and thanks to my ex Brit army mate I always had a spot in sight, it’s amazing what you will fit into at times.
Thought process three, always but always pick spots and plan your approaches to them as you are tooling along.
3. During my early check and training experience, in fact when I was getting checked out to conduct C&T having by then done a bit of it by one CASA man (or whatever the fed agency was called then) Holga Von (something long name, ex Oz army), he says to me. "You seem to be teaching autos at cruise speed 8 feet, 50 feet or 500 feet, or hovering autos at 300 feet, why not is it that you do not teach them at 40 knots and 250 feet where you seem to operate mostly all day?"
Thought process four, Jawohl! We quickly found some error inducement in pilots doing autos at 250 feet had they been conditioned to do them at 50 feet say and at high cruise settings. That error was to fairly quickly bring the cyclic back thus leaving one with no airspeed at a most uncomfortable height. (Not enough thought process)
There seem to me to be four parts of an auto; 1, entry, 2, decent during auto (range chasing if needed) 3, the termination area - say one knot of airspeed must equal one foot of height 50 /50 is nice where one begins to flare, then 4, the touchdown. It matters not how far one will fly in descent if at all, the main game is to arrive at a nice 'termination area', and the rest should follow. A good entry will easily facilitate this and it is where this discussion started so that brings me to what I do now which is to check out several regimes of our LL practices.
a) Fast cruise at super low level where one will bring a whole lot of pain if the cyclic is brought back too early and slams the T/R into something solid beneath, one first must give the collective a quick flick up, then down again as a small cyclic zoom climb is performed as part of a quick stop technique to arrive comfortably in the 'termination area'
b) More than 50 knots at say 50 feet where one simply enters a quick stop routine, collective going down smoothly as the cyclic aft is being applied to arrive at the same height and now established in the 'termination area'. Less than 50 knots down to say 25 knots, leave the A/S where it is until you intercept a 'termination area' further down, but that collective must be got down smartly.
c) At 50 to 250 feet and between thirty and seventy knots, under no circumstances do I want to see a quick check back on cyclic, cos it may hurt you when I thump you and me if it turns real and you have run us right out of airspeed in that nasty height area.
d) Normal cruising at a higher height as between 40 knots and above, checking back on cyclic is not necessary as it may condition you to a bad mistake in tighter circumstances, refer point 1 para 2.
e) Very slow A/S or hover at LL. This procedure is checked at 300 feet after demonstration and follow thru, and at lower heights it is demonstrated only with power recovery and always positioned to reach a target spot. Here I use the point process. Point everything you got brother at your spot, collective, cyclic and right pedal. The RRPM will not decay too much and can be easily got back in hand after about 80 to 120 feet which is where the A/S will again be approaching 60 knots. Do not check back on cyclic until the aircraft is pointed downwards, then I will calmly say, “60 knots attitude please - not 600”, it is then quite a large check back. First couple of demos as hands off I ask them to strongly monitor both the RRPM and A/S. it only takes a second to get down that first bit with the cyclic forward and the RRPM will be still be in the green.
I often use the analogy of the F/W being a bit high on finals; one can simply quickly dive off the extra altitude without increase of speed to arrive a nicer height, so too do we dive off height with the point process to arrive at a safe 'termination area' with enough inertia still in our M/R. You may even be lucky enough to have picked up a small extra airspeed which can be flared off to help arrest ROD. In all slow entries either maintain or increase your A/S if possible. I.E. Do not check back on cyclic at entry.
In all instances I talk a lot about ROD being at the very minimum you can achieve at ground level as high ROD is what will kill you.
It is incredibly important that the auto RRPM must be set up as the Manufacturer describes in the manual. If it is too high ground the A/C as it is too easy to slam the collective down and increase the ROD too much, and I have the back to prove it.
There are four items that need to be completed and checked when an entry to auto is required; 1. collective down RRPM in the green, 1. Set the A/C attitude for max range A/S or the desired A/S under the circumstances, 1. Safe to reach a spot or already turning into wind. 1. Get a mayday out.
Note the generic priority, one doesn’t need to psyche oneself to think about a mayday, just hold the blessed xmit button down while you are briefing others or whatever. Any person listening to a radio is an attentive person, they will do something to help.
Autos from higher heights can induce errors in a pilot's range assessment if auto flight is continued after joining needles. The glide path then changes, so when joining needles at say 300 feet fly away and look away.
Please fly a little higher and a little faster if possible and no passengers while doing Air-work.
None of the above is a recipe for survival or designed as a pissing contest from a predicted height A/S combination say, as every A/C and day is different. It is amazing how easy it is on a very cool, windy day and, lightly loaded compared with a muggy, hot day with a heavy A/C.
MERRY XMAS tet.
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Hello again to the PPrune crew. This is Pete Gillies, away for a couple of days doing my day job.
As before, I extend special thanks to FH1100 Pilot for his great support in getting this simple message across to the many readers and contributors to this thread. And yes, Ray Prouty is at the top of my list of helicopter aerodynamics gurus. In fact it was at one of his lectures years ago that I picked up the first clue of what turned out to be my quest to make Cyclic Back an integral part of getting into a survivable autorotation.
It's been a long day for me here at our "left coast," but I promise to contribute again tomorrow. Guys, it's so simple: Here is is again: Power fails. Cyclic back and lever down, simultaneously or in that order. Pick a place to land. Make that spot.
Works every time but the cyclic back part is not needed from a hover.
We're already writing new software for power failures when on autopilot. And guess what? Cyclic back and lever down simultaneously! Duh. Lever down and then cyclic back? No way in hell...
This Cyclic Back thing is the Swiss Army knife of what to do when you are caught completely by surprise by a power failure while in forward flight. Can't remember anything else? Do this and you'll have a flyable helicopter all the way to the ground or water.
And for you non-mil pilots... Take a look at how many times and for how long your left hand is off of the lever during a typical flight. God gave us left legs so we could steady the lever conveniently while our left hand was, ah...well, you know...ah...hmm...have to be politically correct here...so YOU insert here (_______________) what sort of things you do with your left hand while flying SPIFR, for instance. As I said in a previous post, the lever (collective for all you Yanks) :-) is nothing more than a thrust control, a beta control. Set it and forget it for many types of missions. And it's a great place to rest your left hand, too.
Hey, I'll stop now and save something for tomorrow. My sincere thanks to all of you who support Cyclic Back in any way, shape or form. I'm buying the beer for all of you!
Pete
I just reread my original post, the one that began this thread, and I see that I definitely made a mistake when I said that if the rotor rpm drops more than about 5% below low green or the lower red line (same thing), the flight is over. I should have said it may be over. In posts following that initial one I agreed that the absolutely critical rotor rpm may be well below that figure, but "low red" is determined after many, many flight tests that cover a particular make and model and just about every conceivable variation in D/A, airspeed, flight weight, center of gravity and things I haven't mentioned and probably have never heard of. The sales department wants the rotor rpm operating range to be from zero to infinity, but the engineering department seems to have difficulty reaching those limits.
So to those of you who have been bashing me about this "over" statement, please ease up a bit. I apologize for my initial choice of words. Let the un-powered rotor rpm drop below 5% below low red line and the flight MAY be over. Good luck to you if you want to explore that region without an engine to back you up.
So to those of you who have been bashing me about this "over" statement, please ease up a bit. I apologize for my initial choice of words. Let the un-powered rotor rpm drop below 5% below low red line and the flight MAY be over. Good luck to you if you want to explore that region without an engine to back you up.
It's been a long day for me here at our "left coast," but I promise to contribute again tomorrow. Guys, it's so simple: Here is is again: Power fails. Cyclic back and lever down, simultaneously or in that order. Pick a place to land. Make that spot.
Works every time but the cyclic back part is not needed from a hover.
We're already writing new software for power failures when on autopilot. And guess what? Cyclic back and lever down simultaneously! Duh. Lever down and then cyclic back? No way in hell...
This Cyclic Back thing is the Swiss Army knife of what to do when you are caught completely by surprise by a power failure while in forward flight. Can't remember anything else? Do this and you'll have a flyable helicopter all the way to the ground or water.
And for you non-mil pilots... Take a look at how many times and for how long your left hand is off of the lever during a typical flight. God gave us left legs so we could steady the lever conveniently while our left hand was, ah...well, you know...ah...hmm...have to be politically correct here...so YOU insert here (_______________) what sort of things you do with your left hand while flying SPIFR, for instance. As I said in a previous post, the lever (collective for all you Yanks) :-) is nothing more than a thrust control, a beta control. Set it and forget it for many types of missions. And it's a great place to rest your left hand, too.
Hey, I'll stop now and save something for tomorrow. My sincere thanks to all of you who support Cyclic Back in any way, shape or form. I'm buying the beer for all of you!
Pete
Last edited by PeteGillies; 20th Dec 2013 at 01:33. Reason: Want to add more information
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henry, Pete was offering to buy the beers.
Not lolly water
I'll have either a
or a
Then I'll shout one for you, even though I'm more an energy management proponent
Not lolly water
I'll have either a
or a
Then I'll shout one for you, even though I'm more an energy management proponent
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From someone who doesn't know...
It's been interesting, reading the thread. I don't think I could learn to fly a helicopter now, but I understand the broad theory. I know fixed wing pilots have trouble switching to gyrocopters. After climbing to avoid an obstacle they naturally push the stick forward to gain airspeed. That unloads the rotor and it's off for a quick post mortem.
Therefore, speaking with all the authority of an old coward, it seems two things about helicopters are important: if the engine fails you don't have any time to think, so you'd better have a repertoire of reflexes.
If you're hovering to do a job, you're probably waiting for something to go wrong. If you're cruising along thinking about beer, you twitch the stick back and buy a bit of time to think.
Note. There are many factory-built gyrocopters available now. Some are enclosed side-by-side. Germany and Italy make superb machines.
Therefore, speaking with all the authority of an old coward, it seems two things about helicopters are important: if the engine fails you don't have any time to think, so you'd better have a repertoire of reflexes.
If you're hovering to do a job, you're probably waiting for something to go wrong. If you're cruising along thinking about beer, you twitch the stick back and buy a bit of time to think.
Note. There are many factory-built gyrocopters available now. Some are enclosed side-by-side. Germany and Italy make superb machines.