cattletruck

Look at it another way.

Most of us have an endorsement on some kind on a teetering head machine. We know that if we let the machine head towards zero g (or enter head banging mode) the rotor disk is then free to do as it wishes and often wants to bump the mast and detach itself.

When the g's are decreasing in forward flight most of us instinctively load the rotor with cyclic, not collective - it's ingrained, and it is regardless of what type of rotor head is fitted by the manufacturer. Even those with FW endorsements already know that secret .

chopjock

TC
I'm sorry I do not understand this. If you are cruising at 150Kts and both donks quit, maintain attitude? Well what is the max range autorotation speed all about then?
I'm sure it's not 150Kts.

John Eacott

Guys, one size does not fit all. Zotting along at <50 feet there is no way that my reaction is going to be 'lower the lever' after a loss of power. I'll be pulling the cyclic back to get a bit of height plus convert speed into Nr, then sorting out further actions like collective, etc. If I'm in an OGE hover (or slow speed at height) I'm going to get the cyclic forward to pick up airspeed as well as dropping the lever, totally different reaction.

Autos are energy management; you have three lots of energy (height, airspeed and Nr) to manipulate and arrive safely on the ground. How you manage that is dependent on many factors and there is no initial reaction that fits all of the possible entry scenarios.

Dogmatic posts such as the OP don't seem to have grasped that reality.

topendtorque

Quote:

When the g's are decreasing in forward flight

Seems you have the wrong phallic-sy in hand. Think about it for a tad.

cheers tet

cattletruck

tet, I meant in the context of no engine power, I think that's what you're refering to, please forgive me I failed sarcasm .

FH1100 Pilot

First of all, PHI has been teaching that "Cyclic Back" thing since the 1990s. In Recurrent Training the instructors taught us that our first response to an engine failure in cruise was to start the cyclic coming back...get the nose up...then lower the pitch.

And so I come down squarely with Pete Gilles and HeliComparitor on this. If the engine fails in cruise you must not merely - as Whirlybird huffily suggests - bring the cyclic back to just maintain attitude. Rather, you must get the nose up above the horizon to get the relative wind underneath.

If you're humping along at cruise and the engine quits, lowering the collective will introduce a strong nose-down tendency. The helicopter will immediately start to descend. Bringing the cyclic aft to maintain the cruise attitude will do nothing to correct this; you're still coming down. You have to bring the cyclic even further aft...get the nose up to get the rotor into autorotation. If you're flying a helicopter that cruises faster than it autos, why *not* take advantage of its ability to maintain altitude after the engine failure as you look for a place to land? Why not?

Now, if you're cruising along up at altitude it probably doesn't matter which you do first. If you push the collective down and see the RPM decreasing, your normal instinct will be to load the rotor with aft cyclic. Hey, you have time...what's the diff?

But what if you're dogging along down low...down at 500 feet, or lower, as many pilots do? You might not have an exact spot picked out for your auto (the auto that you're not really anticipating anyway). Trouble is, you neither have the time nor altitude to spare getting the thing set up for an auto. Every foot of altitude is precious. From 500 feet, lowering the collective without a corresponding large aft cyclic input is guaranteed to start an immediate descent. That could seriously limit your choice of landing zones, depending on the terrain.

I was puzzled at the infamous crash of that EMS ship in Missouri back in 2011. I was puzzled because the NTSB said it hit the ground so quickly after the engine quit. I think the NTSB figured that it was about nine seconds or thereabouts from engine failure to impact. And I thought, "How could that be? There's always time. Isn't there?"

I suspect that the pilot was probably frantic. He absolutely knew he was running out of fuel. His landing area (the airport) was in sight but the field boundary was still about a mile away. By this time he'd probably and involuntarily started a descent. So he was probably low...really low. He was screaming along, with the nose down and the rotor at a nose-low attitude toward the relative wind. Then it quit. His first response was to...to text his girlfriend that he'd be late for dinner...wait!...no!...no time for that!...just lower the collective!! Only that put him in an unexpected nose-down descent which was apparently not recoverable.

So Pete and HC, I'm with you guys. Stay the course! But I'll add that - from cruise now...if you don't want to descend - you not only have to make an aft cyclic input to *maintain* attitude, but get the cyclic further back and get the tip path plane tilted *up* and get some air underneath the disk.

G0ULI

It appears to me that everyone is in agreement that if the engines stop, the collective lever is lowered and appropriate movements of the cyclic control need to be made immediately. The exact order that this is done and the extent of the control movements necessary depend on the type of helicopter and the flight regime at the time. The key to a successful autorotation seems to be that the control inputs are made within only a couple of seconds depending how close the helicopter is being operated to the avoidance curves. Given a couple of hours flying at night, base in sight, perhaps a bit of chat going on with the observers, you're chilled and relaxed and suddenly both engines stop. How many helicopter pilots could honestly say that they would have mantained control and performed a successful autorotation to the ground? Given the apparent reliability of twin engined helicopters generally, it surely would take at least a couple of seconds to suspend disbelief at what had just happened before the brain engaged and corrective action was initiated, by which time it is too late. That doesn't address the question of what caused the engines to stop suddenly, but given the circumstances known so far, I'm fairly convinced that very few pilots would have managed a survivable landing. For the purposes of this statement, just assume that getting the helicopter anywhere on or in the vicinity of the ground with the cabin intact would do. The links to the helicopter flying manual and other documents have been very informative, thanks to everyone who has posted those.

Adroight

I had the good fortune to train at a time when almost all return flights to the training airfield were autorotations to the ground with the engine at idle. We became quite proficient.

These days the only autorotaions I do are in the simulator once a year from 3000', day VMC, runway straight ahead with plenty of warning and 9/10 times the Nr drops to the low 80%'s before recovery and occassionally I still mess up the landing.

I would not like to imagine a scenario of losing both engines at night at 1000' over a city in a steep turn.

xlsky

that makes sense even for a FW pilot
makes even more sense if cruising a heli at higher speeds at low altitude..

The Scottish police heli operated quite often below 500ft over the City and especially the deprived areas to keep the ned's under control. especially Friday nights. Sometimes below roof top height of the tower blocks. I believe they do some random patrol on the way back from called missions until fuel gets low.

Nigel Osborn

I fail to see why an EOL will be any different if the helicopter has 1 engine or 2 engines or 3 or more engines if they are all stopped. A Wessex 5 autoed the same as a Wessex 1, a Bell 205 much like a bell 212 & a Bolkow 105 much like most non bell singles. Once you are good at autos, it hardly matters what the helicopter is.

Pulling back the cyclic in the cruise sounds stupid to me, why slow down if you needed to go faster for range for example. Get into the auto & then see what your best options are.

Mick Strigg

On raising the collective, a helicopter pitches nose up. On lowering the collective it pitches down. This is due to the differential of lift across the disc and the effect of the airflow on the horizontal stabiliser.

therefore, on entering autorotation, you have to apply aft cyclic to prevent the nose pitching down.

Try it!

madflyer26

Perhaps HC is correct and a lot of civilian pilots going onto become commercial pilots don't understand the potential of the cyclic flare during the entry into autorotation. Dick Sandford agrees and his article would testify to that.

MSA Mornington Sanford Aviation articles "Enough skill to kill yourself"

During my PPL skills test in Scotland I was shown a low height high speed auto where the very experienced ex military examiner never lowered the collective at all until the speed was at 60 knots. I am sure some on this forum know the gentlemen I am on about. I am grateful I was shown this as I can attest that none of the instructors prior to him demonstrated this or explained it!

Peter is fundemenatlly correct but perhaps using the big paintbrush will offend some.

Regards
MF26

ShyTorque

The discussion here has shown that the op's claim (use of cyclic) is no secret. It's only when and how much that's' worth arguing about.

sunnywa

When I was a QFI at the (then) ADF Helo School in Canberra, we used to teach the students combinations of cyclic and collective movements to enter auto dependent on the circumstances, and each to an EOL in a AS350BA.
The most fun one was 50ftAO at 100kts when we wound back the throttle. Initial action was to freeze collective and flare to the nose was about 10NU and we would shoot skywards up to about 250ft (the theory being to get as much height as you can to find a good place to park). After the att was NU, we slowly reduced the collective to maintain the Nr. At 70kts, lower att (lever fully down by now) to adopt normal 65 kt auto att. Nr horn would blare as the anti flare from the non violent bunt lowered the Nr, but approaching 150ft, first bite into flare and Nr would come up nicely, horn would silence, and into normal flare to land.
Another type of LL auto would be a level one at 50ft when you flared to maintain height and used lever for Nr control then final hook into flare to land.
For normal cruise flight auto entries, normally lever down slowly and att raise to get the Nr back into the green, then when flying again, look around for pad. At auto spd att adjust and manoeuvre as reqd.
I don't think you can be prescriptive one way or the other but depends ont eh circumstances.
I think the priority should be to control and contain the emergency and (in this case get the Nr back up into the green however you can, combination of both lever and cyclic) then look around for options (safe flight in auto going somewhere you want).
I have found all these posts quite fascinating as it shows that, even after all these years of flying helicopters, there are so many different opinions as to how to do it correctly. Sometimes there are many wasy to skin a cat.

HeliComparator

sunnywa, your ways seem eminently sensible to me!

Savoia

Complete engine failure, Bell 206 (belonging to Team Lotus founder Colin Chapman) in September 1980, flying at 120kts (approx.) at 900ft (due to low cloud). We were on our way to Imola in Italy (the only year the Grand Prix was not hosted at Monza). PPRuNer TRC, accompanied by the late great John Ackroyd-Hunt, flew to Norfolk within two hours of the incident as part of the post-engine failure response/rescue.

My godfather was engrossed in the business of unfolding maps when ..

- There was a kick in the aircraft's yaw
- I heard the engine wind-down
- The engine-out caution warnings illuminated and sounded
- My godfather let loose of his maps and assumed control of the aircraft

The response to autorotation was something of a joint venture in that in the second or two which passed between feeling the aircraft yaw, to the moment my godfather assumed control, I was already applying corrective rudder and making cyclic adjustments to maintain a level attitude. These adjustments happened instinctively .. you could perhaps say 'automatically' in that my hands and feet were actively 'engaged' with cyclic and rudder so that when the aircraft's profile was affected by the loss of power, it was 'natural' to correct them.

As my left hand was on my lap at the time of the engine failure .. and given my godfather's 'lightning' response .. he was the one who initiated the reduction in collective .. but, as it happened, an adjustment to cyclic input took place fractionally before he lowered collective and which, as I say, was instinctive in that the 'natural' response (when flying by visual reference) to an uncommanded change in attitude (at least for me) was that you instinctively sought to correct this.

My godfather went on to perform what I can only describe as being a 'perfect' zero-forward-speed touchdown across the furrows of a deeply ploughed field without so much as a scratch on the little Ranger (oh .. I mean JetRanger).

What I can say, following this experience, is that whatever happens immediately following an abrupt and complete loss of power is completely reactionary. If you were to say to yourself "Oh my, how odd, what is going on here" .. that would be too late (at least in a single below say a height above ground of around 1,000ft) .

I was astonished, and I mean astonished, at how quickly everything happened. One moment we were in the cruise .. then .. about 60 seconds later we were on the ground in a field in the middle of what seemed to be nowhere .. in a helicopter with its rotors having almost completed their wind-down. I remember it was extremely quiet after we landed.

Single-engine pilots are trained to continually identify prospective landing areas along their journey's way but .. even with this instinct fully aroused .. once you are faced with a 'live' engine failure it works a little differently to the 'theorised' procedure. The first response is absolutely and unequivocally that of 'sorting-out' the aircraft; regaining controlled attitudes and regulating Nr. As you are doing this you are looking at where you are going to go (not where you would like to go). Depending on your height (we didn't have much) the radius of autorotational flight can be startlingly limited.

Though my godfather taught me to fly from an early age, I had to receive formal training for my initial licence and which task fell to late great Sqn Ldr Anthony 'Antonio' 'Nobby' Clarke who Dennis 'Denissimo' Kenyon had installed as Chief Flying Instructor at his new operation at Booker in the early 80's.

I have to say that Tony taught a 'collective down' policy (as indeed did the late Colin Bates former Chief Pilot of Air Hanson and with whom I flew a base-check in the former Ferranti 206 G-AZZB). But, in both cases, they taught 'attitude control' (meaning cyclic input) as a measured response according to the 'profile' of the auorotation, ie. was it a long or short distance auto, were there turns, was it steep/shallow etc.

This emphasis on preserving (and thereafter controlling) Nr through a reduction in collective (in my mind at least) assumed that cyclic input would be commensurate with the 'automatic' changes in aircraft attitude following a loss of power and which in practice (as per the real life event described above) is what happened.

One needs also to recognise the subtle differences between simulated and actual emergencies. In simulated autorotations you know precisely where you will land. When you encounter an unexpected actual engine failure you do not (at least not to begin with). In simulated autorotations you are 'prepared' (and in most cases with hands and feet fully engaged with all controls) whereas with an actual engine failure you are not specifically prepared any may not have 'active interface' with the flying controls. As mentioned, my left hand was on my lap in the scenario described above but .. it could have been different. Colin Chapman's 206 (because of the frequent travel to European Grand Prix) was fitted with a Collins 3 axis autopilot. Mercifully .. I had not engaged it for the cyclic-mounted disable switch was only available from the right-hand seat (which I was occupying) and not from the dual cyclic where my godfather sat. Having to disable the autopilot from the panel would have been an unwanted and I would add .. dangerous distraction in our particular scenario although I am sure that my godfather would have pushed through the autopilot's breakthrough force had he been required to do so.

In summary:

* In a single engine when experiencing a real life power failure (or I suppose even a twin with a simultaneous double-engine power failure) the preservation of Nr is critical.

* This is accomplished by means of manipulation of the flight controls in which a reduction of the main rotor pitch is essential to sustain autorotation and where adjustments to cyclic input will affect the quality of that autorotation.

* At a height of 1,000ft or less, the radius of autorotational flight is limited and in an actual 'event' the number of suitable landing locations can be similarly limited (unless you happen to be over a level and open area).

* In a real life scenario, you will select your landing area only once you have regained control of the aircraft and are established in autotation.

* While practicing simulated engine failures overhead an airfield at a prepared height one can execute all manner of 'autorotational gymnastics' such as 180° turns and the like (and which at the time seem effortless), in an actual engine failure scenario your 'option' of available landing areas will be 'presented' to you and one of the first things you discover is that time is not on your side.

* During an autorotational descent you will manipulate the aircraft by means of high/low Nr to shorten/extend autorotational range and by means of cyclic inputs (and corresponding pedal adjustments) such as are necessary to set-up the aircraft to perform an arresting flare in front of (or overhead, depending on zero-forward speed touchdown or run on) the landing area you have identified.

* Everything is going to happen faster than you imagined.

I grew up with the knowledge that my godfather was an accomplished aviator and had heard many fascinating recollections of 'brave flight' between him and his former test flying colleagues (the likes of Peter Wilson, Sox Hosegood and Donald Farquarson to name but a few) but .. on that day in Norfolk I gained an enduring respect for his flying abilities.

He was quiet literally unfolding our route maps at the time, to the point that they obscured his forward field of view so that when the engine failed he (initially) had no awareness of what lay ahead. From this totally unprepared condition he assumed control of the aircraft and executed, as mentioned, a perfect autorotation.

But, I will say again, even for him, it was 'instinctive' and I would add .. in an actual emergency is when your training will shine through. It is actually impressive to see how the 'mind and body' can respond, instinctively and instantly, when confronted with a situation which demands dispatch from both.

.

Mick Strigg

One of the demonstrations that we used to give students on the RN Gazelle course was an Nr Decay Demo. We would get the student to put his hand on the roof-mounted throttle lever and then stare at the Nr guage.

From 90kts and on a countdown of three, we would get the student to chop the throttle and the instructor would say "F*** me, the engine's failed!" and then lower the collective fully. In that short time, the Nr would have reached the red-line minima, so a flare would be required to regain the Nr.

The instructor would then complete a perfect EOL to a specified spot!

Savoia

Ah yes, that sounds just like some former QHI's I know!

Fortyodd2

Chris Scott,
Fair point. However, the "basics" in this instance are to get the lever down, control Nr and attitude. What happens next depends on a large number of type, altitude, speed, etc factors.
Apart from a fairly large application of rudder, I cannot image that the drills you would have used on the A320 suffering an engine failure at FL 300 & 500Kts would be the same as those in a Dakota on a half mile final.

SASless

The "Move the Cyclic Aft" concept works in certain situations, does not apply in others, is more important sometimes depending upon the type of aircraft being flown, and most importantly depends upon how quickly the Pilot responds to the Loss of Engine Power moving the rotor blades.

So as is so typical of "Cook Book" Piloting....anyone who clings to a singular approach or method to flying helicopters is just being flat assed stupid.....and in some circles....dangerously ignorant and arrogant.

The extreme display of the use of the "Move it Aft" concept is high speed, low level flight, where a fixed collective or even increased collective and an aggressive cyclic climb maneuver sets one up for a standard autorotation after a several hundred foot gain in height above the ground. The other end of the the spectrum is when doing an OGE Hover or very low forward speed autorotation....moving the Cyclic Aft isn't going to do a thing for you. The area in between the two is where there is so much room to be creative while entering the autorotation. How you manipulate the controls is directly dependent to the situation including whether you have a low inertia or high inertia rotor system. One benefits more from the Cyclic movement than does the other.


DB,

Is it they let the pitch attitude decrease or does the Sim demand an Aft movement on the Cyclic? What Airspeed was the failure initiated? How long did it take for the Pilot to respond?

I suggest you tell us more about the situation yourself.....as you were there it should be easy for you to do. What was the scenario....how were the Pilot's briefed....what were their backgrounds and experience....language differences?

More importantly....were any of them British Trained? How many had CAA ATPL's?