Cyclic Back - Please Read
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Cyclic Back - Please Read
This is a copy of a story that we ran and I thought I would ask for feedback from members.
Two serious accidents with several important aspects in common. Was engine failure the culprit, or was the accident pilot induced?
The Ontario PD had just released its MD500E from the department’s maintenance facility. The helicopter departed Ontario Airport on a post-maintenance flight with two crewmembers on board.
The flight on that day in late June 2002, quickly went wrong. The engine failed during climbout and crashed on Mission Blvd just south of the Airport. The pilot, seated in the left front seat, sustained critical injuries. The mechanic, seated next to the pilot, sustained serious injuries.
Less than four months later and just ten miles from the site of the Ontario accident, a San Bernardino Sheriff’s MD 600 crashed shortly after takeoff. The flight departed for an afternoon patrol mission from the Sheriff’s facility at Rialto Airport. Minutes later, an engine failure brought the aircraft down in a residential neighborhood south of the airport. As in the Ontario accident, the pilot was the more seriously injured of the two-man crew.
The wreckage of each aircraft also was similar. When I saw photographs of the two accidents aircraft side-by-side, I began to notice a pattern. Both photos indicated that the helicopters impacted the ground extremely hard, with the first point of impact on the pilot’s side. In the case of the MD 600, the right skid apparently did not even touch the ground. The photos also show that the rotors were turning quite slowly at the time of impact. Some blades on each helicopter appeared to have little, if any, damage.
Both helicopters were climbing at the time the engines quit, without any warning whatsoever. Both ships had audible and visual low-rotor-rpm warnings that would sound whenever the rotor rpm dropped by approximately five percent from normal. In the case of the 500E, the low-rotor-rpm horn and light activate at approximately 98%, with normal rpm being at 102% to 104% of N2. For the MD 600, the warning activates at approximately 95%, with normal rpm being at approximately 100%. In both cases, the audible and visual low-rotor-rpm warnings activate well before ‘low green’ rotor rpm is reached.
However, in the case of a sudden and complete engine failure, it’s not unusual that the pilots simply don’t recognize such sounds, given the shock and surprise of the event. The engines went from climb power to zero power in an instant. Both pilots were caught completely by surprise.
With the collective positioned for climb power, the reduction in rotor rpm was severe and almost instantaneous. Both pilots reacted as quickly as they could, but clearly not quickly enough. Each pilot said he bottomed the collective while pushing forward on the cyclic to gain or regain airspeed. With the pilot staying ever mindful of the possibility of total loss of power during climbout, bottoming the collective must become a reflexive response. Pitch down and cyclic forward; this is a very common, almost instinctive reaction to such an emergency in a helicopter.
Pushing the cyclic forward can be a deadly mistake at a time like this. In this case only down collective is appropriate. Pushing the cyclic forward doesn’t prevent entry into autorotation, but it does not help it, either. Prompt down collective will cause entry into autorotation regardless of cyclic input, but the resulting minimum rotor speed will be lower with forward cyclic. A positive, smooth aft movement of the cyclic is what may be required, provided that forward airspeed is significant.
Aft cyclic will definitely minimize loss of rotor rpm. But what constitutes ‘significant forward airspeed’? Those who have done a lot of height-velocity testing like Don Armstrong believe that something in the neighborhood of 45+ KIAS is a reasonable threshold. Below about 35 KIAS it would be of little help.
I don’t believe it’s accurate to say that there is a threshold below which aft cyclic may not be beneficial. As I teach at Western Helicopters, any forward airspeed is justification for starting the cyclic back immediately. This is especially true in the takeoff profile. My experience at Western Helicopters indicates that moving the cyclic back never causes a problem, even if it is not significantly effective. So do it, and do it immediately!
The rotor system is not in the autorotation mode of flight unless, and until,the airflow is passing upward through the rotor blades. During powered, forward flight, air is being pulled down through the rotor from top to bottom. Just pushing the collective down does not reverse the airflow, at least not in the critical entry into autorotation. Pushing the collective down does, of course, reduce the drag of the rotor system and thereby reduces the rate of rotor rpm decay. Aerodynamicist Ray Prouty points out that the rotor disk actually tips forward as the blades move to minimum pitch, making it even more imperative to move the cyclic aft very quickly.
All helicopter pilots should know that every helicopter rotor system has an rpm below which recovery to normal rpm cannot be attained without the help of the engine. This critical rpm is not marked on the rotor tach but is generally estimated to be around 80% rpm.
The FAA does not require that this catastrophic threshold be defined, or tested to confirm it. Aerodynamic analysis can predict it for a given set of assumptions—weight, altitude, temperature, airspeed, airfoil design—but it must clearly be below the minimum rotor speed limit (redline). Type certification testing involves in-flight demonstration of safe recovery from five percent below the minimum redline rpm, usually done at speeds in the vicinity of Vy. The 80% figure is a reasonable assumption of that catastrophic threshold rpm.
It is my opinion that the rotor systems of both of these helicopters entered this critical area from which normal (in the green range) rotor rpm could not be regained, regardless of altitude, attitude, airspeed or flight maneuvers. Before either pilot reacted, the rotor rpm was below the normal operating range. But this alone isn’At catastrophic — momentary dips below minimum redline rpm can be expected with sudden complete engine failures. But the assumption in certification is that the collective will be lowered promptly to the downstop, and that is borne out during height-velocity testing, where all heights at and above the knee involve an arbitrary delay of at least one second before lowering the collective.
Under similar circumstances, I believe very few helicopter pilots, regardless of experience or flight hours, could have reacted quickly enough to avoid having the rotor rpm drop below the green range. The combination of climb power and total surprise is potentially deadly. This is precisely the challenge to flight instructors—reducing the number of pilots who tend to ignore the risk of engine failure—by instilling good, reflexive reactions to sudden failures.
In the MD 500 series helicopters, sudden engine failure at slow airspeed and high power calls for the immediate application of aft cyclic. Sure, if you have hands on the cyclic and collective at the time the engine quits, then moving collective down to the stop should coincide with the aft cyclic movement. But to delay bringing the cyclic back until the collective is down is wrong.
I base this opinion on my observations of pilots who operate their helicopters with no hands on the collective. This is especially true for pilots flying single-pilot from the left seat, such as in the MD 500 and MD 600. In these machines, pilots routinely remove their left hand from the collective, holding it in position with their leg and/or applying friction to it, while they fly the cyclic with their left hand and use their right hand for something else, such as adjusting the radios.
Although this is certainly not an ideal situation, it’s what occurs in the real world. One hand is always on the cyclic. By all means, lower the collective as soon as you can, but meanwhile, get the cyclic moving aft to preserve as much of the rotor rpm as possible.
At Western, we teach that any autorotation entry that involves pushing the cyclic forward is an automatic failure. One of our teaching techniques involves asking a student to touch the fire extinguisher on the left-front doorpost of the 500D to see if it is vibrating too much, and then we chop the throttle. We demand that the cyclic be started back instantly, while the student gets a hand back on the collective and starts it down. To see how critical this really is, repeat this process in a helicopter with a reciprocating engine, when the rotor rpm falls much more quickly than in something powered by a free-turbine engine.
The height-velocity curve is a constant reminder of the need for airspeed, but at the time the engine quits, the airspeed indicator is the least important instrument in the cockpit. The rotor tach is the only instrument of any importance at a time like this. We must remember that we are flying a rotary-wing aircraft, and all of our wings need to have airspeed above stall in order for them to function. Pitot-tube airspeed is of no consequence whatsoever, unless and until the rotor is back in the green.
It would be wonderful if, at the onset of an engine or driveline failure, all instruments on the panel, except the rotor-tach would go blank and stay that way until the rotor-tach is back in the green. Once the rotor rpm is back in the green, the pilot can attempt to regain airspeed if needed, and if time and altitude allow.
Pushing the cyclic forward at a time like this may well increase the airspeed, but at the expense of rotor rpm. With the rotor rpm in the “never-never” range, from which recovery cannot be made, the helicopter then becomes a falling object. My theory is that, in the early stages immediately after the engine fails, the retreating blades stall quickly, if the collective is not immediately lowered.
Retreating blade stall may cause the aircraft to begin a roll to the left. This would account for the fact that the accident aircraft ended up on their left sides. The blades on the advancing side are still producing a certain amount of lift, although they too will quickly stall if the rpm continues to slow.
When the rpm falls below that catastrophic threshold and the entire rotor stalls, regardless of airspeed, the sink rate increases and response to cyclic input is lost. The pilot loses all control of the direction of the flight. With the entire rotor stalled, response to cyclic inputs is virtually non-existent. At this point the pilot is just along for the ride. Directional control is lost, and the helicopter begins rolling to the left. This explains the hard landing on the left side of each aircraft. By extension, we should expect a rightward-rolling tendency on clockwise-rotating rotor systems, such as the Eurocopter AStar.
The exact altitude of the accident helicopters at the time of engine failure is not definitively known, but estimates place them between 250 feet and 500 feet AGL. It is my belief that if the helicopters had been significantly higher above the ground when the engines quit, the crews probably would not have survived. As they descended, both helicopters were picking up speed as their rotors slowed down, and additional altitude would have made the crash forces worse than they were.
Part II on Next Post.
Part II.
The exact airspeed at the time of each engine failure is also unclear. But the height-velocity curve is not a factor in either of these accidents. The main factor is the initial cyclic input being moved forward rather than aft.
No doubt that the NTSB reports will cite engine failure as the cause of these two accidents. Clearly, it initiated an unfortunate chain of events, but the real culprit was rotor rpm. The rpm dropped to the point where recovery was impossible. At that point, the crews were simply along for the ride. Directional control was lost, and because of the very low rotor rpm, there was virtually no kinetic energy remaining in the rotor system. The final pitch pull was of little, if any, value in reducing the crash forces.
In addition, retreating blade stall caused the helicopters to roll to the left before ground contact, greatly decreasing the crashworthiness of the airframe and the effectiveness of the pilot and passenger restraint systems.
The message is this: If the engine fails in forward flight with pitch applied, start the cyclic back immediately. Get the collective down as quickly as possible, but this alone will not stop the decay of the rotor rpm, especially if the pilot is pushing the cyclic forward for any reason.
--------------------------------
Thanks for any comments and opinions.
Ned
Two serious accidents with several important aspects in common. Was engine failure the culprit, or was the accident pilot induced?
The Ontario PD had just released its MD500E from the department’s maintenance facility. The helicopter departed Ontario Airport on a post-maintenance flight with two crewmembers on board.
The flight on that day in late June 2002, quickly went wrong. The engine failed during climbout and crashed on Mission Blvd just south of the Airport. The pilot, seated in the left front seat, sustained critical injuries. The mechanic, seated next to the pilot, sustained serious injuries.
Less than four months later and just ten miles from the site of the Ontario accident, a San Bernardino Sheriff’s MD 600 crashed shortly after takeoff. The flight departed for an afternoon patrol mission from the Sheriff’s facility at Rialto Airport. Minutes later, an engine failure brought the aircraft down in a residential neighborhood south of the airport. As in the Ontario accident, the pilot was the more seriously injured of the two-man crew.
The wreckage of each aircraft also was similar. When I saw photographs of the two accidents aircraft side-by-side, I began to notice a pattern. Both photos indicated that the helicopters impacted the ground extremely hard, with the first point of impact on the pilot’s side. In the case of the MD 600, the right skid apparently did not even touch the ground. The photos also show that the rotors were turning quite slowly at the time of impact. Some blades on each helicopter appeared to have little, if any, damage.
Both helicopters were climbing at the time the engines quit, without any warning whatsoever. Both ships had audible and visual low-rotor-rpm warnings that would sound whenever the rotor rpm dropped by approximately five percent from normal. In the case of the 500E, the low-rotor-rpm horn and light activate at approximately 98%, with normal rpm being at 102% to 104% of N2. For the MD 600, the warning activates at approximately 95%, with normal rpm being at approximately 100%. In both cases, the audible and visual low-rotor-rpm warnings activate well before ‘low green’ rotor rpm is reached.
However, in the case of a sudden and complete engine failure, it’s not unusual that the pilots simply don’t recognize such sounds, given the shock and surprise of the event. The engines went from climb power to zero power in an instant. Both pilots were caught completely by surprise.
With the collective positioned for climb power, the reduction in rotor rpm was severe and almost instantaneous. Both pilots reacted as quickly as they could, but clearly not quickly enough. Each pilot said he bottomed the collective while pushing forward on the cyclic to gain or regain airspeed. With the pilot staying ever mindful of the possibility of total loss of power during climbout, bottoming the collective must become a reflexive response. Pitch down and cyclic forward; this is a very common, almost instinctive reaction to such an emergency in a helicopter.
Pushing the cyclic forward can be a deadly mistake at a time like this. In this case only down collective is appropriate. Pushing the cyclic forward doesn’t prevent entry into autorotation, but it does not help it, either. Prompt down collective will cause entry into autorotation regardless of cyclic input, but the resulting minimum rotor speed will be lower with forward cyclic. A positive, smooth aft movement of the cyclic is what may be required, provided that forward airspeed is significant.
Aft cyclic will definitely minimize loss of rotor rpm. But what constitutes ‘significant forward airspeed’? Those who have done a lot of height-velocity testing like Don Armstrong believe that something in the neighborhood of 45+ KIAS is a reasonable threshold. Below about 35 KIAS it would be of little help.
I don’t believe it’s accurate to say that there is a threshold below which aft cyclic may not be beneficial. As I teach at Western Helicopters, any forward airspeed is justification for starting the cyclic back immediately. This is especially true in the takeoff profile. My experience at Western Helicopters indicates that moving the cyclic back never causes a problem, even if it is not significantly effective. So do it, and do it immediately!
The rotor system is not in the autorotation mode of flight unless, and until,the airflow is passing upward through the rotor blades. During powered, forward flight, air is being pulled down through the rotor from top to bottom. Just pushing the collective down does not reverse the airflow, at least not in the critical entry into autorotation. Pushing the collective down does, of course, reduce the drag of the rotor system and thereby reduces the rate of rotor rpm decay. Aerodynamicist Ray Prouty points out that the rotor disk actually tips forward as the blades move to minimum pitch, making it even more imperative to move the cyclic aft very quickly.
All helicopter pilots should know that every helicopter rotor system has an rpm below which recovery to normal rpm cannot be attained without the help of the engine. This critical rpm is not marked on the rotor tach but is generally estimated to be around 80% rpm.
The FAA does not require that this catastrophic threshold be defined, or tested to confirm it. Aerodynamic analysis can predict it for a given set of assumptions—weight, altitude, temperature, airspeed, airfoil design—but it must clearly be below the minimum rotor speed limit (redline). Type certification testing involves in-flight demonstration of safe recovery from five percent below the minimum redline rpm, usually done at speeds in the vicinity of Vy. The 80% figure is a reasonable assumption of that catastrophic threshold rpm.
It is my opinion that the rotor systems of both of these helicopters entered this critical area from which normal (in the green range) rotor rpm could not be regained, regardless of altitude, attitude, airspeed or flight maneuvers. Before either pilot reacted, the rotor rpm was below the normal operating range. But this alone isn’At catastrophic — momentary dips below minimum redline rpm can be expected with sudden complete engine failures. But the assumption in certification is that the collective will be lowered promptly to the downstop, and that is borne out during height-velocity testing, where all heights at and above the knee involve an arbitrary delay of at least one second before lowering the collective.
Under similar circumstances, I believe very few helicopter pilots, regardless of experience or flight hours, could have reacted quickly enough to avoid having the rotor rpm drop below the green range. The combination of climb power and total surprise is potentially deadly. This is precisely the challenge to flight instructors—reducing the number of pilots who tend to ignore the risk of engine failure—by instilling good, reflexive reactions to sudden failures.
In the MD 500 series helicopters, sudden engine failure at slow airspeed and high power calls for the immediate application of aft cyclic. Sure, if you have hands on the cyclic and collective at the time the engine quits, then moving collective down to the stop should coincide with the aft cyclic movement. But to delay bringing the cyclic back until the collective is down is wrong.
I base this opinion on my observations of pilots who operate their helicopters with no hands on the collective. This is especially true for pilots flying single-pilot from the left seat, such as in the MD 500 and MD 600. In these machines, pilots routinely remove their left hand from the collective, holding it in position with their leg and/or applying friction to it, while they fly the cyclic with their left hand and use their right hand for something else, such as adjusting the radios.
Although this is certainly not an ideal situation, it’s what occurs in the real world. One hand is always on the cyclic. By all means, lower the collective as soon as you can, but meanwhile, get the cyclic moving aft to preserve as much of the rotor rpm as possible.
At Western, we teach that any autorotation entry that involves pushing the cyclic forward is an automatic failure. One of our teaching techniques involves asking a student to touch the fire extinguisher on the left-front doorpost of the 500D to see if it is vibrating too much, and then we chop the throttle. We demand that the cyclic be started back instantly, while the student gets a hand back on the collective and starts it down. To see how critical this really is, repeat this process in a helicopter with a reciprocating engine, when the rotor rpm falls much more quickly than in something powered by a free-turbine engine.
The height-velocity curve is a constant reminder of the need for airspeed, but at the time the engine quits, the airspeed indicator is the least important instrument in the cockpit. The rotor tach is the only instrument of any importance at a time like this. We must remember that we are flying a rotary-wing aircraft, and all of our wings need to have airspeed above stall in order for them to function. Pitot-tube airspeed is of no consequence whatsoever, unless and until the rotor is back in the green.
It would be wonderful if, at the onset of an engine or driveline failure, all instruments on the panel, except the rotor-tach would go blank and stay that way until the rotor-tach is back in the green. Once the rotor rpm is back in the green, the pilot can attempt to regain airspeed if needed, and if time and altitude allow.
Pushing the cyclic forward at a time like this may well increase the airspeed, but at the expense of rotor rpm. With the rotor rpm in the “never-never” range, from which recovery cannot be made, the helicopter then becomes a falling object. My theory is that, in the early stages immediately after the engine fails, the retreating blades stall quickly, if the collective is not immediately lowered.
Retreating blade stall may cause the aircraft to begin a roll to the left. This would account for the fact that the accident aircraft ended up on their left sides. The blades on the advancing side are still producing a certain amount of lift, although they too will quickly stall if the rpm continues to slow.
When the rpm falls below that catastrophic threshold and the entire rotor stalls, regardless of airspeed, the sink rate increases and response to cyclic input is lost. The pilot loses all control of the direction of the flight. With the entire rotor stalled, response to cyclic inputs is virtually non-existent. At this point the pilot is just along for the ride. Directional control is lost, and the helicopter begins rolling to the left. This explains the hard landing on the left side of each aircraft. By extension, we should expect a rightward-rolling tendency on clockwise-rotating rotor systems, such as the Eurocopter AStar.
The exact altitude of the accident helicopters at the time of engine failure is not definitively known, but estimates place them between 250 feet and 500 feet AGL. It is my belief that if the helicopters had been significantly higher above the ground when the engines quit, the crews probably would not have survived. As they descended, both helicopters were picking up speed as their rotors slowed down, and additional altitude would have made the crash forces worse than they were.
Part II on Next Post.
Part II.
The exact airspeed at the time of each engine failure is also unclear. But the height-velocity curve is not a factor in either of these accidents. The main factor is the initial cyclic input being moved forward rather than aft.
No doubt that the NTSB reports will cite engine failure as the cause of these two accidents. Clearly, it initiated an unfortunate chain of events, but the real culprit was rotor rpm. The rpm dropped to the point where recovery was impossible. At that point, the crews were simply along for the ride. Directional control was lost, and because of the very low rotor rpm, there was virtually no kinetic energy remaining in the rotor system. The final pitch pull was of little, if any, value in reducing the crash forces.
In addition, retreating blade stall caused the helicopters to roll to the left before ground contact, greatly decreasing the crashworthiness of the airframe and the effectiveness of the pilot and passenger restraint systems.
The message is this: If the engine fails in forward flight with pitch applied, start the cyclic back immediately. Get the collective down as quickly as possible, but this alone will not stop the decay of the rotor rpm, especially if the pilot is pushing the cyclic forward for any reason.
--------------------------------
Thanks for any comments and opinions.
Ned
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Just one point ....
Retreating blade stall may cause the aircraft to begin a roll to the left. This would account for the fact that the accident aircraft ended up on their left sides. The blades on the advancing side are still producing a certain amount of lift, although they too will quickly stall if the rpm continues to slow.
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Great articles...
I don't want to arm-chair quarterback this one, but the article re-inforces my belief that aft cyclic should be applied at the same time the collective goes down. This is similar to a recent discussion, here...
http://www.pprune.org/forums/showthr...5&pagenumber=1
I wonder how many folks train for a engine failure during the initial take-off? Even under controlled circumstances, that training can be dangerous. Here is an NTSB summary of a hard landing that occured as a result of simulating engine failure during normal take-off profile. I like the above articles reference that everything outside of RRPM is secondary...
http://www.ntsb.gov/ntsb/brief.asp?e...23X05200&key=1
http://www.pprune.org/forums/showthr...5&pagenumber=1
I wonder how many folks train for a engine failure during the initial take-off? Even under controlled circumstances, that training can be dangerous. Here is an NTSB summary of a hard landing that occured as a result of simulating engine failure during normal take-off profile. I like the above articles reference that everything outside of RRPM is secondary...
http://www.ntsb.gov/ntsb/brief.asp?e...23X05200&key=1
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Randy Bechtel specialises in engine failures on takeoff in the 407..... 
Sod the airspeed - use what you've got, even if you have to do a vertical.
Phil
Sod the airspeed - use what you've got, even if you have to do a vertical.Phil
Where I train(ed), engine failures from the climbout are done on a regular basis with experienced instructors and advanced students - it's not something I saw until I was on my CPL(H) modular course.
In an R22 they don't last long, but with rapid and simultaneous lowering of the lever, application of aft cyclic and right pedal they're survivable.
In an R22 they don't last long, but with rapid and simultaneous lowering of the lever, application of aft cyclic and right pedal they're survivable.
The Original Whirly
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The first time I had an engine failure from the climbout demonstrated to me in the R22 was on my FI course. Come to think of it, that's was probably the first time I had an instructor with enough experience for it to be safe to demonstrate it!!!!!!!
Bear in mind the surprise factor here too, if it's for real. I actually found the demonstration quite an eyeopener. I don't pull the trim in the climbout any more...or do anything else; my left hand stays right on that lever. But to be totally and brutally honest, I still don't think you should place any bets on survival of an unexpected engine failure on the climbout in the R22...well, not if I'm flying it anyway.
Autorotate, brilliant post. I would agree - aft cyclic is essential to get all the RRPM you can; forward cyclic will reduce it. And RRPM is a lot more important than airspeed.
In an R22 they don't last long, but with rapid and simultaneous lowering of the lever, application of aft cyclic and right pedal they're survivable.
Autorotate, brilliant post. I would agree - aft cyclic is essential to get all the RRPM you can; forward cyclic will reduce it. And RRPM is a lot more important than airspeed.
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All the way through my initial training despite being told about engine failure at take off being a very serious situation, it was not phyically shown to me until I asked the very experienced, yearly check FI to help me with it, he showed me, it was stunningly quick (this was in the R22), like most others I never take my hand off the lever( to twiddle radio dials or anything else) until well airborne and at least 300 ft.
Strangly my initial instructor was happy to show me the EOL from cruise, but never once at take off or just into transition, I made a point of performing the practice EOL at least once every week, this may seem to be overegging the practice routine but it worked for me, for whilst held aloft in the air by bits of moving metal you need to be totally assured that you have the correct reactions to acsend with as much control as you can have.
Vfr
Strangly my initial instructor was happy to show me the EOL from cruise, but never once at take off or just into transition, I made a point of performing the practice EOL at least once every week, this may seem to be overegging the practice routine but it worked for me, for whilst held aloft in the air by bits of moving metal you need to be totally assured that you have the correct reactions to acsend with as much control as you can have.
Vfr
I'm a little bit puzzled by this thread. In fact, I'm quite astounded that anyone could be "surprised" by an engine failure on take-off. Blimey, aren't we supposed to be prepared for that?
Typically, most accidents happen in the take-off or landing phase of flight, and this makes logical sense. And it should tell us something. I have made, by conservative estimate, over 50,000 take-offs in my career (10,000 hours at an average of about six landings per hour). And I can say with confidence that an engine failure would never have taken me by surprise. Why not? Simply because I keep that thought in the back of my mind, even when I am flying twins. Sure, there's a lot going on in any given take-off as you manage the various tasks, but the human brain is an amazing device. It can keep track of more than one thing at a time.
And it is not as though I fly around scared like a Chihuahua all the time. It's not like I've become a nervous, shifty-eyed paranoid, predictor of doom. Far from it. It's just that I've just come to an understanding about flying. An engine WILL quit, it's not a question of "if." Okay, I accept that. No big deal.
We must not be surprised by an engine failure - ever! But most especially we must not be surprised by it on take-off. That's our job.
There is so much more to helicopter flying than can be condensed into the Basic Helicopter Handbook. Posts like the one that started this thread and the other related one about autorotation entries go a long way toward enlightening and educating pilots about these strange machines and how they work. Good show!
Typically, most accidents happen in the take-off or landing phase of flight, and this makes logical sense. And it should tell us something. I have made, by conservative estimate, over 50,000 take-offs in my career (10,000 hours at an average of about six landings per hour). And I can say with confidence that an engine failure would never have taken me by surprise. Why not? Simply because I keep that thought in the back of my mind, even when I am flying twins. Sure, there's a lot going on in any given take-off as you manage the various tasks, but the human brain is an amazing device. It can keep track of more than one thing at a time.
And it is not as though I fly around scared like a Chihuahua all the time. It's not like I've become a nervous, shifty-eyed paranoid, predictor of doom. Far from it. It's just that I've just come to an understanding about flying. An engine WILL quit, it's not a question of "if." Okay, I accept that. No big deal.
We must not be surprised by an engine failure - ever! But most especially we must not be surprised by it on take-off. That's our job.
There is so much more to helicopter flying than can be condensed into the Basic Helicopter Handbook. Posts like the one that started this thread and the other related one about autorotation entries go a long way toward enlightening and educating pilots about these strange machines and how they work. Good show!
Cool as a moosp
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Your experiences as related concur with mine. Until I did CPL level training the engine failure on take off was not mentioned. When it was taught it came as a welcome surprise.
Interestingly enough, Nr F, your instructor was the first person to teach it to me. This after about 250 hours on type.
These days I sit in the hover and do the usual checks before departure, but the one I add now is the mental rehersal of what to do in the next 30 seconds with an engine failure. Heck I've been doing that before take off for thirty years with a plank wing, why has it taken so long for me to realise that it is vital in a heli too?
Interestingly enough, Nr F, your instructor was the first person to teach it to me. This after about 250 hours on type.
These days I sit in the hover and do the usual checks before departure, but the one I add now is the mental rehersal of what to do in the next 30 seconds with an engine failure. Heck I've been doing that before take off for thirty years with a plank wing, why has it taken so long for me to realise that it is vital in a heli too?
The Original Whirly
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moosp,
It was The Nr Fairy's instructor who taught helicopter EFATO to me too. And he also told me it was part of the PPL syllabus, that no-one should be sent solo without having been shown engine failure in every part of the circuit. Common sense tells me he's right...though I've been panicking at the mere thought of teaching it.
In fact, I have no intention of doing so without more experience, and I certainly wouldn't expect every instructor to be able to. But...shouldn't all pilots be learning it, pre-PPL, pre-first solo? As PF1 says, engines can fail at any time.
It was The Nr Fairy's instructor who taught helicopter EFATO to me too. And he also told me it was part of the PPL syllabus, that no-one should be sent solo without having been shown engine failure in every part of the circuit. Common sense tells me he's right...though I've been panicking at the mere thought of teaching it.
In fact, I have no intention of doing so without more experience, and I certainly wouldn't expect every instructor to be able to. But...shouldn't all pilots be learning it, pre-PPL, pre-first solo? As PF1 says, engines can fail at any time.
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I teach my students from very early on that the engine will quit, and it's not going to be at 5000' 110 kts, when there is plenty of time to react. I teach them in the climbout, in high power situations, usually when we are talking or I have thier mind focused elsewhere, because thats when it is going to happen and the lowering of the collective along with aft cyclic (the amount depending on airspeed) maintaining rotor RPM is absolute paramount. At the same time I want them to learn to react instinctively, and I also want them to say to themselves before every takeoff,what they would do if the engine quits and to be prepared for it.
Hopefully this will someday save their lives........
I too, am surprised to hear that these pilots were "taken by surprise" when the donkey quit.......
Hopefully this will someday save their lives........
I too, am surprised to hear that these pilots were "taken by surprise" when the donkey quit.......
Whirlybird
As an aside, I am interested in what kind of experience the average instructor that taught you had then? What kind of experience do you have now that you are teaching yourself?
Just wondering.
The first time I had an engine failure from the climbout demonstrated to me in the R22 was on my FI course. Come to think of it, that's was probably the first time I had an instructor with enough experience for it to be safe to demonstrate it!!!!!!!
Just wondering.
Whirly, if I may answer for you.
coyote:
Mike Green has squillions of hours, a large proportion of them instructional, and a large proportion of those in the R22.
Pete Vellacot and Tom Saunderson have thousands of hours apiece, loads on R22 instructing.
I'd feel safe with any of those three showing me something new - mostly because I know I can say "I'm not happy with this" or bacause I know they'll monitor me closely.
coyote:
Mike Green has squillions of hours, a large proportion of them instructional, and a large proportion of those in the R22.
Pete Vellacot and Tom Saunderson have thousands of hours apiece, loads on R22 instructing.
I'd feel safe with any of those three showing me something new - mostly because I know I can say "I'm not happy with this" or bacause I know they'll monitor me closely.
Helicopter Pilots Get It Up Quicker
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...PPL training seems a long time ago but I too was taught that if the engine is going to stop it will ALWAYS pick the most dangerous/unexpected/surprising/inconvinent time to do so and to be ready for it.
I still fly around after several different type conversions and (only) a couple of hundred hours since the R22 with my left hand on the collective, when it's not being used to do something else...
Even been told off for driving with left hand on handbrake before! (There's a story to that one which could have been very embarrassing...)
I still fly around after several different type conversions and (only) a couple of hundred hours since the R22 with my left hand on the collective, when it's not being used to do something else...
Even been told off for driving with left hand on handbrake before! (There's a story to that one which could have been very embarrassing...)
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So now that you guys have read the story do you think the author is onto something here, is he going down the wrong track.
I have had a lot of emails re this story, both for and against and would like to know if this is correct or not.
Thanks
Ned
I have had a lot of emails re this story, both for and against and would like to know if this is correct or not.
Thanks
Ned
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It's not clear cut, black and white. Therefore, it is difficult to properly choose a "side," if there is one. Only the pilots in the story will know all the details... they experienced it. Environment and individual experience shouldn't be substituted with a one-size fits all approach.
However, I haven't seen anyone reply on this forum that they agree with each pilots actions (forward cylic to get airspeed). In fact, it seems that the consensus is that aft cyclic should be automatic and damb the airspeed (until RRPM is okay).
However, I haven't seen anyone reply on this forum that they agree with each pilots actions (forward cylic to get airspeed). In fact, it seems that the consensus is that aft cyclic should be automatic and damb the airspeed (until RRPM is okay).
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With any single engine helicopter having an engine failure, the top priority must be to lower collective.
Then check your other parameters, height, airspeed, suitable landing spot. For example if you are cruising at 1000 ft or higher at 110 kts, why immediately reduce speed to 65 kts.( Assuming that is the recommended auto speed ) if you can not now reach a good landing area ahead of you. Maybe you will need max range speed of 90 kts with minimum rrpm to stretch your glide to reach a good field past the 200 ft trees or buildings.
After t/o you basically land straight ahead, so you don.t have so many options other than to establish auto with sufficient rrpm to cushion the landing.
Too many pilots always want to do a big flare at the bottom and then level and hopefully make a slow run on. Great over a flat area and if you are in current practice. Over hilly or forest terrain, I used to teach a vertical auto so that you could let yourelf into a hole in the jungle. To fully demonstrate this point, I used to flare at any height, 1000 ft or more, and drop vertically into wind at the wind speed which meant no ground speed. Initially of course most pilots found this tricky because it was against their ab initio training but soon realised it was a life saving technique in certain conditions. I also found more pilots who weren't in current practice did a constant speed auto better than trying to do fancy flares and low level leveling.
Then check your other parameters, height, airspeed, suitable landing spot. For example if you are cruising at 1000 ft or higher at 110 kts, why immediately reduce speed to 65 kts.( Assuming that is the recommended auto speed ) if you can not now reach a good landing area ahead of you. Maybe you will need max range speed of 90 kts with minimum rrpm to stretch your glide to reach a good field past the 200 ft trees or buildings.
After t/o you basically land straight ahead, so you don.t have so many options other than to establish auto with sufficient rrpm to cushion the landing.
Too many pilots always want to do a big flare at the bottom and then level and hopefully make a slow run on. Great over a flat area and if you are in current practice. Over hilly or forest terrain, I used to teach a vertical auto so that you could let yourelf into a hole in the jungle. To fully demonstrate this point, I used to flare at any height, 1000 ft or more, and drop vertically into wind at the wind speed which meant no ground speed. Initially of course most pilots found this tricky because it was against their ab initio training but soon realised it was a life saving technique in certain conditions. I also found more pilots who weren't in current practice did a constant speed auto better than trying to do fancy flares and low level leveling.
Good thread.
I believe there are some good words of wisdom in the article, and I can agree with the sentiment, but I cannot agree with the solution. As RD says above a "one size fits all" is not the best option. We have enough syllabus hours to teach the student what auto entry technique to use, when, and why.
There are some other points that I wish to raise with the article:
It seems to emphasise aft cyclic in preference to lowering the collective. This I cannot agree to except in TWO instances: the low level "pop up" where you trade altitude for airspeed/RRPM in an effort to avoid overshooting a good landing spot, OR to sacrifice airspeed in an attempt to regain badly lost RRPM. The article covers the second instance, and I fully agree here, aft cyclic MUST be applied when RRPM is not recovering, or is recovering too slowly. The simple priority I have found useful in teaching emergencies like this is:
RRPM is life fix it first - ie Maintain RRPM first,
Then maintain airspeed if possible,
only then maintain altitude if you have to.
Sacrifice altitude and airspeed in order to obey "RRPM is life"! Twins or singles.
What this translates into when relating to the article, correct take off technique is paramount. Use a gate at an appropriate height (we use 100 ft in UH-1H) to hit climb speed. Climb at best auto speed plus about 10 - 15kts, again 70 - 75 kts in the UH-1H which autos at about 60 - 65 for min RoD. Then if you suffer an engine failure you achieve several things:
1. Lower collective as per any other auto entry technique.
2. Maintain nose attitude (resist forward, apply aft ONLY if RRPM continues to degrade) with cyclic as you lower RRPM.
3. Enter normal flare auto flare and landing/cushion.
4. Change shorts.
In other words, during engine failure after take off (EFATO) in the UH-1H, you are entering the normal flare for an autorotative landing with about the right airspeed and some up the sleeve for RRPM recovery if required. Works in all types I have flown so far, but its the UH-1 where I can best remember the numbers.
What worries me about the article is that it is emphasising an aft cyclic solution to a problem that has it's root cause in take off technique (See RD's "reinforced" belief that aft cyclic is required). My opinion is that if you applied aft cyclic following an EFATO at 200 ft and 50 kts, then you will end up with the same results as the article is attempting to avoid. Thus I stress that the one solution is dangerous to pursue and therefore I do not believe that the authour is "on to anything". What about an auto at an OGE hover at 1000ft AGL?
The testing for certification is not quite explained by the article. It allows for a "reasonable" pilot reaction - not a perfect pilot, nor a terrible pilot - and it assumes that you are following published profiles such as take off techniques. thus if you are changing the radio, scratching your ar5e, a slower than normal pilot, and are a couple of knots slow for your hieght on take off, you are NOT covered by the certification!
Lastly, I take issue with the statements about the blades slowing down faster on non turbine aircraft. With all due respect Sir: bolloxs! Blades slow faster dependant upon inertia at time of failure, and drag applied (ie pitch). That is why a BK 117 blades slow down a whole lot faster that a B47 regardless of engine type!
Any discussion about this topic is good, and the article certainly stimulates that. Well done.
I believe there are some good words of wisdom in the article, and I can agree with the sentiment, but I cannot agree with the solution. As RD says above a "one size fits all" is not the best option. We have enough syllabus hours to teach the student what auto entry technique to use, when, and why.
There are some other points that I wish to raise with the article:
It seems to emphasise aft cyclic in preference to lowering the collective. This I cannot agree to except in TWO instances: the low level "pop up" where you trade altitude for airspeed/RRPM in an effort to avoid overshooting a good landing spot, OR to sacrifice airspeed in an attempt to regain badly lost RRPM. The article covers the second instance, and I fully agree here, aft cyclic MUST be applied when RRPM is not recovering, or is recovering too slowly. The simple priority I have found useful in teaching emergencies like this is:
RRPM is life fix it first - ie Maintain RRPM first,
Then maintain airspeed if possible,
only then maintain altitude if you have to.
Sacrifice altitude and airspeed in order to obey "RRPM is life"! Twins or singles.
What this translates into when relating to the article, correct take off technique is paramount. Use a gate at an appropriate height (we use 100 ft in UH-1H) to hit climb speed. Climb at best auto speed plus about 10 - 15kts, again 70 - 75 kts in the UH-1H which autos at about 60 - 65 for min RoD. Then if you suffer an engine failure you achieve several things:
1. Lower collective as per any other auto entry technique.
2. Maintain nose attitude (resist forward, apply aft ONLY if RRPM continues to degrade) with cyclic as you lower RRPM.
3. Enter normal flare auto flare and landing/cushion.
4. Change shorts.
In other words, during engine failure after take off (EFATO) in the UH-1H, you are entering the normal flare for an autorotative landing with about the right airspeed and some up the sleeve for RRPM recovery if required. Works in all types I have flown so far, but its the UH-1 where I can best remember the numbers.
What worries me about the article is that it is emphasising an aft cyclic solution to a problem that has it's root cause in take off technique (See RD's "reinforced" belief that aft cyclic is required). My opinion is that if you applied aft cyclic following an EFATO at 200 ft and 50 kts, then you will end up with the same results as the article is attempting to avoid. Thus I stress that the one solution is dangerous to pursue and therefore I do not believe that the authour is "on to anything". What about an auto at an OGE hover at 1000ft AGL?
The testing for certification is not quite explained by the article. It allows for a "reasonable" pilot reaction - not a perfect pilot, nor a terrible pilot - and it assumes that you are following published profiles such as take off techniques. thus if you are changing the radio, scratching your ar5e, a slower than normal pilot, and are a couple of knots slow for your hieght on take off, you are NOT covered by the certification!
Lastly, I take issue with the statements about the blades slowing down faster on non turbine aircraft. With all due respect Sir: bolloxs! Blades slow faster dependant upon inertia at time of failure, and drag applied (ie pitch). That is why a BK 117 blades slow down a whole lot faster that a B47 regardless of engine type!
Any discussion about this topic is good, and the article certainly stimulates that. Well done.
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Helmet Fire - One thing I should mention is that the article was aimed more at MD500/600 series specifics, or at least thats what I was told by the author.
Hope that helps.
Ned
Hope that helps.
Ned
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Extremely important to keep RRPM in the green above anything and everything else. The airspeed doesnt mean anything if the blades stall, the altitude doesnt mean anything (except a further fall) if the blades stall. If you keep the RRPM in the green and have zero airspeed and end up right in the middle of the HV curve you are still better off, atleast then you have control over the aircraft and even though you may be dropping like a rock and have no way to flare at the end, you still are falling slower than if your blades had stalled and in that case you still wouldnt be able to flare.
I think the routine training of 75 knots, 500' AGL auto entries is what gets us into this horrible habit. When we train we never want to trade off airspeed for RRPM because it is never really that low (not a big surprise to get a simulated failure in training) and if we do give up our airspeed we have to get it back and it makes more work. I found myself fall into the trap when at about 300 hours instruction I had a student lower the collective about halfway and roll the throttle off when we got a traffic alert during instrument training. I was bent over looking for the traffic, a little complacent, and a lot confused to be hearing the horn on an instrument flight. I lowered the collective still trying to figure out what happened and looked at the RRPM which was at about 88 percent. I just keep the collective full down and waited for the RRPM to build. It wasnt until the RRPM was at about 95 percent that I realized I could just pull back on the cyclic more and get the RRPM into the green and start looking for that traffic again. I had plenty of altitude, all ended well, but its now always on my mind to use that airspeed when you need it above all else.
As a side note, as an instructor in the R22 my hand is always on the collective on take offs and landings, no matter the student level.
I think the routine training of 75 knots, 500' AGL auto entries is what gets us into this horrible habit. When we train we never want to trade off airspeed for RRPM because it is never really that low (not a big surprise to get a simulated failure in training) and if we do give up our airspeed we have to get it back and it makes more work. I found myself fall into the trap when at about 300 hours instruction I had a student lower the collective about halfway and roll the throttle off when we got a traffic alert during instrument training. I was bent over looking for the traffic, a little complacent, and a lot confused to be hearing the horn on an instrument flight. I lowered the collective still trying to figure out what happened and looked at the RRPM which was at about 88 percent. I just keep the collective full down and waited for the RRPM to build. It wasnt until the RRPM was at about 95 percent that I realized I could just pull back on the cyclic more and get the RRPM into the green and start looking for that traffic again. I had plenty of altitude, all ended well, but its now always on my mind to use that airspeed when you need it above all else.
As a side note, as an instructor in the R22 my hand is always on the collective on take offs and landings, no matter the student level.