Are engine failures always recoverable in helicopters?

[AnthonyGA]

Assuming there's a large flat space on which to land, are engine failures always recoverable in a helicopter? I read on another site that an engine failure below 90 feet AGL or so is sure to result in a crash. I've heard of autorotation but don't know much about it, nor do I know much about helicopter flying in general. So, assuming a good pilot and flat terrain on which to land, how hard is it to land safely after a powerplant failure (everything else intact, just a total loss of power)?

[Three Blades]

In short - no.
To save typing out the whole theory, take a look at this:
Height-velocity diagram - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Height-velocity_diagram)

[atpcliff]

Hi!

It depends, but, basically, with an engine failure, you autorotate to a safe landing area that is into the wind, and everyone walks away with no aircraft damage.

Obviously, there are variables.
Like:
If you are hovering, at, say, 100', then you are probably dead.
If there is an unsafe area, you are probably dead.\
Hovering at 5-20' or so, no problem.
All of the above also depends on the helicopter.
In the Huey, with an engine failure in a 5' hover, you could land safely, pick it back up to a 5' hover, rotate the helo 180 degrees, and then land safely AGAIN. I would guess that would not work in a Robinson R-22.

Landing the helo out of an autorotation is more difficult than landing a cessna-172 with an engine failure (more like a typical landing), but it is definitely do-able, as long as there are no negative factors (see above).

cliff
NBO

[Epiphany]

Depends on lots of variables - type of helicopter, airspeed, height, AUW, ability, wind, level of training etc. If all variables are favourable then there is a good chance of walking away from the arrival. If not then the outcome is debatable.

[GoodGrief]

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For more go to YT and search for "autorotation", there're plenty.

[GoodGrief]

Landing the helo out of an autorotation is more difficult than landing a cessna-172 with an engine failure

May I doubt that?

[Gomer Pylot]

If you are hovering, at, say, 100', then you are probably dead.
May I doubt that?

[dipperm0]

No, defenetly no.

A twin ( or more) engine helicopter, operated under CAT A limitation will NEVER crash if the pilot knows and applies the procedures depicted in the flignt manuel and mass limitations accordingly.

The engine failure may occurs in hover in ground effect, out of ground effect, during take off, in flight, nothing dramatic will happens and the pilot will land the helicopter safely either on an helipad or a runway.

Obviously, to reach such level of safety means mass reduction and appropriates procedures.

Dauphin N3 exemple: the N3 is CAT A approved on runway or unobstructed strip and helipad of at least 68 ft diameter. If the helipad is less than that, no CAT A available, thus, cat B flight and then, the safety during take off is no more guaranteed.

[Um... lifting...]

Well, the operative question for the OP is: "How many engines did you have when you started? 1? 2? 3?" In the latter two cases, unless the machine is old and in certain regimes, it's probably quite recoverable. Depends upon the performance characteristics of the aircraft in question. In the first case, it's not 'recoverable' if we mean continuing flight. But if we mean having the airframe be reusable, quite possibly.

Landing a helicopter out of an auto is (generally) a significantly briefer evolution and takes up a lot less real estate than landing an airplane of equivalent size. Difficulty depends a lot on what you've been trained to do. Most folks with a fair amount of Bell time can do a zero-speed auto entry from 100' and safely land the aircraft with a very low touchdown speed... in a Bell.

I'm often asked by non-pilots if it's "harder to fly a helicopter". My answer is: "not for me".

Just like airplanes, in general, the bigger the aircraft, the more challenging it is to get it all sorted out and put it on the ground without power without bending the machine or the blobs of protoplasm along for the ride. There are exceptions.

Many among us have autorotated numerous types made by numerous manufacturers to the ground. Some are easier than others. I expect most of us have preferences for aircraft we'd prefer to auto in an emergency if it came down to it.

[GeorgeMandes]

In aviation, it is hard to answer any question that includes the words "always" or "never."

[Pugilistic Animus]

Not a heli pilot but just a few words on the HV diagram
they are composed for standard conditions so any deviation from the assumptions must be approach carefully and conservatively
the two worst areas are the low and slow and the very low and fast

Unfortunately, for me I'd have to spend big bucks for a good instructor but I've always wanted to learn those babies.

[Arm out the window]

Very low and fast isn't bad - freeze collective briefly, cyclic climb, collective smartly down, auto attitude, flare, level, cushion, go to pub.

[Brian Abraham]

Aotw, you forgot the 360° turn!!!!!

[Shawn Coyle]

Gomer (and others)
I have yet to see anyone who has had a real, unannounced engine failure from 100' not have damage to the helicopter and their body. There's a good reason for avoiding that area.
(I've probably done close to 100 demonstrations of the HV curve to budding test pilots and flight test engineers, as well as participated in a few real world HV curve demonstrations for certification, just to establish my bona-fides).
If you've convinced yourself through lots of training for autorotations that you can do a zero airspeed entry from 100' and got away with it, you're deluding yourself that when the real, unannounced failure happens that you can survive - the important part you're not thinking about is the surprise, it can't happen to me, this isn't true part of the real engine failure that deprives you of the very important two to three seconds that the training aspect doesn't consider. You're ready for the engine failure, know what's going to happen and are spring loaded to react to the first twitch of the throttle from the instructor.
and for those of you who think that you can get away with it from a 20' hover, much the same applies.
Everyone I've talked to who's had a real engine failure has said the same thing- the surprise factor caught them big time.
And just to round this out - when doing a zero airspeed entry from a high hover in a Jet Ranger (one of the more forgiving machines to do this in), it takes a minimum of 250-300 feet for the airspeed to start approaching something that will let you flare and have the rotor start to get back into the green. This is with a one second delay between rolling the throttle off and lowering the collective - a very short time.

[212man]

To continue with Shawn's theme - the power loss following a real failure is likely to be more rapid than that resulting from simply rolling off the throttle. This is because the fuel scheduling of the AFCU/FADEC is set to prevent flame out (similarly a carburettor or fuel injection system prevents lean cut.)

So, the combination of anticipation and unrealistic power loss are giving a false sense of security.

[Heli-phile]

This instructor is passing on false expectations.
Just because Robinson euphamisticaly refer to this as the "avoid" curve, do not, for 1 second think this is actually really ok. (even you being a really good pilot and all)

Low speed / Low inertia rotor / Low Level ops will only ever end up in a world of hurt if the donkey really stops.
Frank would not be a happy man to see people deliberately operating and indeed training in this profile - and filming it for broadcast on You-tube no less!!:ugh:

[Lt.Fubar]

Shawn, what you wrote about HV-curve for Vertical magazine would fit here perfectly, unfortunately the older issues are not available online, any chance to pass around the copyright, and have them here?

I have to put a sticker on the monitor reminding me to print all your articles :ok:

[topendtorque]

This is with a one second delay between rolling the throttle off and lowering the collective - a very short time.


with respect - beg yours??


Very low and fast isn't bad - freeze collective briefly, cyclic climb, collective smartly down, auto attitude, flare, level, cushion, go to pub.


Well ahem, that jess depends on how low you really are.
it may well be much better of give the ol' heave ho stick a bit of a flick (then back down again) to position yon backside just a bit further from the ah-field prior to commencing yon flare.

sitting in a 100' hover, flat arsed, power on collective up, that is a real problem in an R22, not so much in some other types. forget the one second delay, you're in the wrong game if'n it takes you that long to sort it. not suggesting for one second that they are rcoverable without danage.

that 100' hover flight position is an indicator of lack of pilot acumen for sure.

rule of thumb is , when at 100' and very little if any A/S always try to plan to have the disc pointed at the ground, or at least the collective down quite aways, just zoomed up there, etc.
cheers tet

[ReverseFlight]

It's really a skill of power management when an engine failure occurs in a single-engined helicopter. Of course some machines have the edge (B206, B47 - providing you don't let high inertia blade rpm droop) but it doesn't mean lower inertia blades aren't manageable, for example, my CPL(H) flight school regularly trained autos down to 50' AGL in their singles (R22s among other types).

I keep reminding fellow helicopter pilots that engine failures are not a matter of "if" but a matter of "when". I have known many highly experienced pilots go through engine failures in their distinguished careers and the only common thread is the surprise and disbelief with the total denial "This isn't happening to me !".

[GoodGrief]

that 100' hover flight position is an indicator of lack of pilot acumen for sure

Guess you haven't done those certain type of jobs then...

[PlasticCabDriver]

Um... lifting...

I'm often asked by non-pilots if it's "harder to fly a helicopter". My answer is: "not for me".


Surely the correct answer is: "Yes, very. Only the finest and most talented have any hope of being able to cope with the superhuman co-ordination and intense mental battering that flying a helicopter requires".

That's what I say anyway....

[Gomer Pylot]

Shawn, et al:

I have no doubt that metal will be bent if the engine quits at 100', but I don't believe that it's certain death. I've done a number of practice autos from ~100', and while it's not the easiest maneuver, it's certainly not a guarantee of dying on the spot. A reasonably proficient pilot should be able to walk away from the scene, or at least be transported to a hospital for treatment.

As for the original question, the answer is obviously "no". Engine failures in automobiles are not always recoverable, nevermind aircraft of any type. There are few certainties in life, and living through any event is not one of them. If events conspire to occur in certain ways, nothing we can do will prevent someone dying, but that isn't often the case, and while engine failures aren't always recoverable, they generally are, at least to the extent that nobody dies.

[Shawn Coyle]

Gomer:
With all due respect - you're setting yourself up for a very hard fall if you think you'll be able to get away injury to yourself if you have a real engine failure in a 100' hover.
Practicing is fine to develop technique and experience, but the real engine failure doesn't give you any advance warning, and the intervention time between figuring out it's an engine failure and doing the necessary thing means you will be plummeting to the ground with reducing rotor RPM and no chance to stop the rate of descent, or get any forward speed.
Try an engine failure in the hover at say 5' AGL, and do not lower the collective when you roll the throttle off. You may only raise the collective. If you're happy with that, try it at increasing heights (do this at maximum weight, by the way). If you get higher than about 8' AGL before you chicken out, I'd be surprised.
If you can show me a real engine failure (in a single engine helicopter) from such a condition where the pilot walked away and there was no damage to the aircraft, I'd a) be incredibly surprised and b) buy the pilot at least one beer/drink of choice.

[Gomer Pylot]

Shawn, reread my post. I said there would be bent metal, and possibly a trip to a hospital, but that death is not certain. I stand by that.

[topendtorque]

that 100' hover flight position is an indicator of lack of pilot acumen for sure Guess you haven't done those certain type of jobs then...

my apols, I should have qualified that, with - when there is no need to especially in a lightie, like an R22 when mustering.

One of the things I spend a lot of time with on C & T is "impressing" those who don't think about that with a heap of hover autos from 300'. Particularly impressive in an R22.

Good Grief, you're back!!:{

As far as, "those types of jobs", well I have only done about 90 or 100 sling endorsements, short, long, pick yer nose, drop a mag on vertical out, because dumkompf didn't check his, all that. Does that answer your statement.


I've done a number of practice autos from ~100',


you're as guilty as me gomer, no qualification. With or without airspeed? heavy or light inertia? Etc.

The real recip usually does give a little warning,

1. fuel starvation, one cough, then silence,

2. magneto drive failure, one cough, then silence. usually more than enough time to galvinise the reactionary mode into top gear well before the sinking bit occurs. Probably all a lot more sudden than a turbine winddown.

3. sinking instantly only occurs with a free wheel failure, believe me, at the same time of course as a god awful horrendous din out the back. more than enough to the scare the livin' daylights out of any decent self respectin' chookhouse for a hundred miles around.

[AnthonyGA]

Just a note to say that I am indeed reading the replies to my original question. It's interesting to see the discussion that has arisen from it; apparently there isn't a real consensus on whether engine failures are universally recoverable or not.

I realize that "always" is a strong word. What I was thinking of was a comparison with fixed-wing aircraft. If you are flying in a fixed-wing aircraft in normal flight (not stalled, and in level flight or a coordinated standard turn, gentle climb or descent, etc.), and the terrain below you is completely flat (think salt flats), it's hard to see how an engine failure could not be recoverable. In every case, you'd be able to glide down to a landing, without hurting yourself or the airplane.

I was wondering if this can also be said of engine failures in a helicopter. You're flying along, or hovering, or are otherwise in some normal regime of flight, and the engine fails completely (or all engines, if you have more than one). Is it always possible to land safely on the salt flat? The original Web page I had read indicated that in certain types of otherwise normal flight, an engine failure means that the aircraft and/or its pilot will be injured or killed. The example given was a failure at 90 feet AGL, which supposedly spells disaster (it was implied that this was from a hovering position at that altitude, rather than forward flight, but I'm not sure).

It sounds like there's a lot of disagreement about whether or not recovery is always possible, and it sounds like it depends a lot on the specific aircraft. I've been looking at YouTube videos of both successful autorotations and unsuccessful ones. The rate of descent is quite harrowing, but apparently that's normal. I think I understand the theory: collective down so that the wind as you descend speeds the rotor up instead of slowing it down, then a flare that reverses the collective so that it briefly produces lift to soften the landing (I hope that's right—probably a vast oversimplification). It looks way, way harder than just gliding onto the ground in an airplane.

In any case, the discussion is interesting.

[check]

Perhaps I was lucky, maybe a little skill boosted by adrenalin, but I walked away from a high hover engine failure with no damage to man nor machine, but then it was pilot friendly machine!

Getting on for 40 years ago carrying out a gunnery shoot in my "trusty" Bell 47G3B1, hovering along a tree line between 50 - 100 feet agl when the donk stopped. Yaw, with a little help from the pedal turned away from the trees, lever down, nose down , nose up ,lever up, on the ground. My heart ticking louder than the cooling turbo charger.

[Gomer Pylot]

If you're talking about an engine failure in cruise flight, I'll take a helicopter every time. You don't need hundreds of feet of ground run for the landing, you can put it down in any open area with little or no ground run. IMO an engine failure in a helicopter is orders of magnitude safer than in a fixed-wing, and much more likely to result in no injuries. Anything is possible, of course, and you can put the aircraft into situations that are unrecoverable in the event of engine failure, just as you can put an automobile into situations that are unrecoverable in the event of engine failure. But in the general case of cruise flight, regardless of altitude, a helicopter is far more likely to be able to do a safe landing, regardless of what is under it, because of the far lower speed necessary. The rate of descent is not harrowing. It is somewhat higher than most fixed-wing, but it's completely controllable, and the touchdown rate of descent is close to nil.

[Ye Olde Pilot]

Well look this. Never let an instructor tell you what to do.In this case the instructor had an argument with the owner regarding throttle settings. You can reach your own conclusions.
http://www.aaib.gov.uk/cms_resources.cfm?file=/Brantly%20B-2,%20N276SA%2008-08.pdf

[Mungo5]

max performance takeoff (say 40 feet), which is standard practice at Palo Alto due to obstructions and the airport layout

I have to ask.. really? I don't know the air/heli port at Palo Alto - but isn't there some way of doing a normal t/o, even if it is down the active r/w?

Sorry, off topic..

[212man]

I have to ask.. really? I don't know the air/heli port at Palo Alto - but isn't there some way of doing a normal t/o, even if it is down the active r/w?

One would have thought so..........or even the parallel taxyway?

http://img.airnav.com/ap/00107.jpg

[[email protected]]

n5296s - well, if you are doing it for pleasure and you now recognise the dangers of a max performance take-off - I presume you will always request departure and arrival from the runway/taxiway from now on.:ok:

An engine is most likely to quit when you ask the most of it during a rapid acceleration.

[ReverseFlight]

An engine is most likely to quit when you ask the most of it during a rapid acceleration.
... or if you reduce power setting, as in lowering the collective when you accelerate through translation/transition.

[charliegolf]

It should be noted that ALL engine failures present the pilot with a situation that is screwupable! It's more certain than the OP's premise.

CG

[[email protected]]

n5296s And for myself, I presume that you are a patronising and pompous fool. Of course, in the nature of presumptions, either or both of us could be wrong, and in fact one of us definitely is.

Well, one of us has been flying helicopters for 27 years and 7000 hours and has seen most (not all) of the mistakes that can be made in a helicopter (of those 27 years, 20 have been as a QHI). As a Flight Safety Officer at various levels it has also been my job to point out where some of the pitfalls lie when operating helicopters. If all that makes me pompous and patronising but helps prevent those who think they know it all from killing themselves then I am pretty content with that.

You know that a max performance take-off puts you at more risk than a normal transition yet you choose to depart from a confined site when an airfield is available - why? To save time? Because it is easier and quicker? You are operating in a no-threat environment for pleasure but you choose the risky option over the safe one - I'll tell you what kills pilots the quickest - arrogance.

Flysafe

[atpcliff]

Hi!

I was initially trained by the US Army, and they did sort of a max performance takeoff as normal.

Then, at USAF transition training, the takeoff was made very close to the ground, getting through translational lift ASAP, and then climbing away. I believe it is much safer the USAF way, and not sure why the Army training was different.

cliff
NBO
PS-If U R cruising at 500' in a helo, and have an engine failure, with good landing places below you, it is no problem.
Recently had a very experienced EMS pilot in KGRB have a tailrotor failure on an avionics test flight, and he did not make it. He avoided killing anyone on the ground, so that was a good thing.

[Mungo5]

why? To save time? Because it is easier and quicker? You are operating in a no-threat environment for pleasure but you choose the risky option over the safe one

Also questions the NTSB, AAIB etc will ask when it all goes t*ts up on the r/w, (or in this case off the r/w.)

[GeorgeMandes]

When watching helicopters depart, I never ceased to be amazed by the number of vertical, down wind or otherwise cowboy departures, when an into the wind, flat disk departure is available.

[GeorgeMandes]

With all due respect, it is often the "most experienced" pilots that are making the cowboy departures. Try one of these doing recurrent at the Bell Training Academy or at Canadian Helicopters, when a flat disk departure is available, and you will get an earful. Often, you can slightly change something, accommodate other aircraft, and still make a safer departure.

[[email protected]]

n5296s - I'll take that as a sort of apology for the 'patronising pompous fool' comment - I presumed you would look at how you operate at Palo Alto in light of some of the informed comments on this thread regarding engine failures - I guess I was wrong.

Your dismissal of exposure time is a form of denial - I don't know how high you go on your towering, max-performance transition but I would guess at least 40' to clear the obstacles and you will be in the avoid curve (H-V curve) from the point you pass about 10' in the climb until you have probably 50' and 40 kts (providing you are then over a clear area with no further obstructions) - a bit more than <2seconds per flight - AND you have to do the reverse on the way back in!

I'm sure the NTSB would understand how your instructor, the operation he works for and the airport all feel that increasing the risk to your pink body is more acceptable than upsetting the FW owners; yes downwash can make the flaps and rudders bang about but you can fit control locks, tie the aircraft down or just park them slightly further away. When was the last time all the users of Palo Alto had a flight safety meeting to discuss operating procedures and safety issues?

Flying in the military tends to breed an element of over-confidence in ones own ability - trust me I know - and spending your formative flying years in a high threat environment colours your judgement regarding risk. Your 10k+ vet isn't flying in a war zone any more - as I'm sure he knows - and should therefore be prepared to explain the risks involved and talk you through the consequenses of an engine failure at 40' and 10 kts in a confined area. If he dismisses your concerns out of hand then you have got the wrong instructor.

Just because the EMS aircraft (is it a single or a twin) does it doesn't make it right either - the economic pressures on EMS operations in the US make them take a lot of risks that are unwarranted - see the many threads on pprune about it or ask Sasless.

The bottom line is that just because you can do it in a helicopter doesn't mean you should and having lots of hours doesn't make you good - just lucky:ok:

[Gordy]

Question--

Just for sh1ts and giggles---How many documented cases, worldwide, of engine failure on take off have there been in the last five years?

[VeeAny]

Gordy

Having just checked the database there a quite a few in both twins and singles.

I can't post a link as the way I filtered it throws up all kinds of other accidents involing engine failure or power loss, not just on take off.

If I manage to cut it down to a sensible list I'll post a link up here.

And a few others that involve operating in the shaded area of the HV Diagram one of which hospitalised a very experienced instructor over here in the UK.

Hardly a quantitative answer like you wanted but definitely more than none.

GS

[busdriver02]

Another thought, those max performance take offs/ high hovers for no reason.... what if instead of an engine failure, you lose part of the tail rotor drive system? Think you can recover that?

[newfieboy]

Here, here Busdriver, I totally agree. I also agree 100% with Shawn.You boys doing 100ft zero airspeed in R22, or any machine, setting yourself up to get bit in the Ass bigtime.We do them every 6 months recurency, cos we have to. Most of our work is in the dead mans curve. And thats in machines with a little more user freindly than a robbie.Mind you we all hate it, even when prepared. I got over 10,000 hours, aprox 85% of that over the Boreal Forest or Zero reference in the artic on longline moving drills, 4000lb pieces in the hover while the riggers set pieces, not a good place to be. But ya know what, I get paid good money to do it, also know the consequences if I lose an engine.Not gonna be good for sure,I accept it cos I minimize the risk everyturn by having a plan, maybe gotta take the big trees only option. you guys doing it in an R22 on Utube all fine and dandy, airport, taxiway, run on landings, yeah great. try an engine failure for real operationally, you;re on the ground before you even get to punch the load.I know, cos I been there. I know alot of guys over in Canada had one, some die some get hurt, no one I know walked away without a visit to the local ER . You guys think your cool posting that on Utube, right, we can all pull tricks at a nice big airport. Like I said, operationally in the real world, you likely gonna kill yourself. If you think you can get away with it cos you pulling stunts like that over an airport, light, with a place to go, and ready for it, forget it. Come on down to Canada, fly with an operational check pilot in the real world. Think you in for a big eye opener.:D

[Two's in]

I think it's fair to say that Military training is pretty much fixated on emergencies because guess what, when someone is shooting at you, you are likely to have an unscheduled exciting moment when it all goes quiet. In all that training, whether single engine or twin engine, the avoid curve is hammered home as a place to really; well avoid actually. Whatever the flight mode when the engine failure occurs, if you are in the unhappy part of the performance graph, stand by to be the first on the scene of the accident in a short space of time.

Just to reinforce the point made by several others, if commercial and military pilots only operate within the avoid curve due to absolute neccessity and fully understanding the risks involved, it's certainly one of life's mysteries why a PPL in a machine whose performance could best be described as "barely adequate" would dick around in that high risk envelope. It can only be a terminal lack of imagination or gross stupidity - or both of course.

[Ag-Rotor]

Newfieboy, it was a pleasure reading your post.Sometimes when you filter through all the dribble on this site you read something from the real world of Heli driving. Safe flying

[GeorgeMandes]

1) Leaving aside the safety considerations of an unnecessary vertical departure, isn't the idea to get your helicopter off the ground and into forward flight with the least amount of power required, so as to know how to finesse the ship when it takes all the power you have?

2) It appears that the original poster removed his posts, and we are merrily carrying on without him.

[[email protected]]

George - at least it's stopped him calling me names - I was very hurt;)

[newfieboy]

Quote;
Just to reinforce the point made by several others, if commercial and military pilots only operate within the avoid curve due to absolute neccessity and fully understanding the risks involved, it's certainly one of life's mysteries why a PPL in a machine whose performance could best be described as "barely adequate" would dick around in that high risk envelope. It can only be a terminal lack of imagination or gross stupidity - or both of course.

Thanks for that quote,being a profesional that dicks around in said envelope and am currently away doing said stupidity, couldn;t have put it better myself. Thanks for the laugh, very true, very ammussing.:ok: