To a powered pilot 300 feet sounds incredibly low, but to put this in perspective to fly the pattern described above with the 4 turns and a landing back at the point of takeoff would require starting at least 1500 feet AGL if you were flying your average Cessna or Piper, and which is hardly an EFATO in the context of this thread.

True, but if there is any wind at all there will normally be a wind gradient and climbing through a wind gradient into wind and descending through a wind gradient downwind are not the same thing. Actually, I do practice turnbacks (because it's fun.......)
and it is a shed load easier with no wind at all....Depends much more on your rate of climb and glide angle than on what rate of turn you use. I can return no wind and land facing take-off direction in a super cub from 400 feet. I don't need to pull to the buffet (don't have a stall warner) ,just a brisk turn, then a genteel sideslip to line up to the landing area and deal with any excess height.

Takes me 600 feet in a DR 400. Gliders are another story again. 300 feet will indeed be enough for a brisk circuit off a wire launch. Aerotow, no, because of the lower rate of climb.

However, I suspect that if I have a real and unexpected engine failure that by the time I have got my arse in gear I probably will end up crashing straight ahead with the aircraft the property of the insurers who have so far made a large profit out of me :(

The examples I gave earlier (Southampton and Bembridge) have the problem that the "major obstacles" are all in front and to the side of you so the only real option may be a turn back (or at least a turn of over 90 degrees), if you CAN land straight ahead then I certainly agree with not turning back, but what to you do when that option is just not realistically there?

Foxmouth, if you are too low for a turnback (given your airplane performance characteristics, the environment and your own ability), and there's also no opportunity to land ahead, or left/right of your track, or anywhere else in reach, then what do you expect us to advice?

The best I can come up with is something I think the RAF was already saying in the 1930s: "Try to hit the softest object available with the least amount of speed."

I was waiting for that question and it is a reasonable one. First off it speaks to the desirability of having a plan before the engine stops, not after, one of the reasons I make my students do a take off brief before every takeoff. This is especially important for difficult airports where a quick decision on angling the aircraft left or right after the engine failure may have a profound impact on the success of the manoever.

I think it is also important to point out that a uniform 9 Gee de-acceleration from 60 to 0 knots requires a ground run of about 25 feet or one fuselage length. The flying schools IMO do students a dis-service because they leave the impression that you have to have some nice long smooth field in order to have a "successful" forced approach. The reality is a survivable landing only requires that the aircraft be upright with and with an approximately level pitch attitude at a low airspeed and have at least a small run after touchdown to moderate the de-acceleration forces ( ie not a head on impact with a solid immovable object)

The best predictor of success for actual real world forced approaches has been that the aircraft was in control when it impacted the ground and that it hit at a spot of the pilots choosing, not a random area.

Finally do not forget that the accident statistics suggest that up to 80 % of all engine failures are directly caused by the pilots actions or inactions so the best way to deal with an engine failure is not to cause the engine to fail in the first place.

True, but you also need to consider that the aircraft brakes are NOT capable of supplying a 9G deceleration. If you want to stop the aircraft within one fuselage length, and live to tell the tale, you need something external to the aircraft to slow it down uniformly. The military does this with arrestor cables on aircraft carriers, but somehow I don't think that's an option in an EFATO scenario.

So if you are going to hit a concrete wall, it really doesn't matter how long the ground run preceding that hit is. Yes, if your ground run before hitting the concrete wall is one fuselage length, the *average* G force will be 9G or thereabouts: One fuselage length of almost zero G (horizontal deceleration), followed by one engine cowling length of 25+ G. Unfortunately your body is not going to care for the average G, but for the peak G.

You need to turn the reasoning around: If you have no place to go that resembles a runway or field, try to find something that gives you the most uniform deceleration along whatever your (crash) landing run is going to be. Wherever that may be. And if you can find something that is able to decelerate your aircraft more-or-less uniformly to a full stop over the length of at least one fuselage, you probably will not be killed by the horizontal deceleration.

As far as the rest of your post is concerned, I agree 100%.

True; which is why I made the comment

The central point, which I think is a failing of todays flight training, is that the crappy patch of rough ground a few hundred feet long that is right in front you is likely to be discounted as a viable option because it doesn't meet the "right" criteria and so pilots are trained to turn towards the "good" field
which in the EFATO scenario is probably too far away or behind them.

For landing on the crappy field, it all comes down to making an accurate touchdown. You can save yourself, if not the aircraft, by landing on a football field - as long as you land on the beginning of it. Land on the far end and hit the brick wall that (let's suppose) is there and things don't look so good. The trouble is that accurate touchdowns are pretty hard to get right and as far as I can see most people don't. I'm always a bit horrified by the number of people who touch down half way down our 2400' runway at Palo Alto. I really do TRY to get it on the numbers myself but I for sure don't always get within a football field of them - and that's an airport I know well, complete with windsock and known altitude.

When I did the 180 power off landing in my CPL I did actually get it on the numbers (phew), provoking a comment from the examiner that "you'd be amazed how many people get this badly wrong". And that's CPL candidates.

I'm extremely grateful for the huge salt marshes off both ends of my home airport!

For Cessna singles retracting the flaps will make them land now if you are in danger of overshooting your touchdown point. However in every case you can make any aircraft land by smashing it into the ground at your chosen point.

Not pretty but much better then running into the brick wall. Remember the only part of the aircraft that has to be intact when you stop is the cabin.

Not talking about a "crappy patch of rough ground" but in one case, open sea, and the other, busy built up industrial areas with all manner of obstacles, and I would suggest if you only have ONE small crappy patch of rough ground surrounded by complete no go areas, the sort of pilot who would reliably get in there probably has the same level of experience as one that might be able to cope with a turnback!

Those are both really great points. We tend normally to be so focussed on a "good" landing that it's easy to forgot them - especially the second one.

Thank you.

PPrune posters seem to very good at finding the one exception that will counter any argument.

Fine you win; a turn back is the only way to deal with an EFATO. Happy now :rolleyes:

At near stall speed, I assume, or you'll still have the energy to get rid of.

Well obviously the lower the speed the better, but if the stone wall is looming in the windshield and you are still in the air then you may have to force the airplane to touchdown now in order to start de-accelerating. This may include full forward stick. This is obviously a desperation move but slamming the airplane on, busting off the nose wheel and a violent stop with the nose digging in will be much more survivable than hitting that stone wall head on at flying speed.


I was at the local flying club yesterday and as it happened the turn back issue got raised by another fellow. He said he saw a for real turn back to a narrow dirt strip by a C 185. The engine failed at about 600 feet AGL and the pilot got it back with a steep bank and a final wild skidding turn to get lined up. He said it was a very impressive example of flying skill. I then asked if he knew why the engine failed. His reply "Oh the pilot forgot to turn the fuel on and the engine died when the collector tank emptied"................

Trying the Impossible Turn
 

I had a go at the Impossible Turn stuff today, albeit with a 2,000' AGL hard deck. The problem with being that high is trying to judge how far you have travelled horizontally for the loss of height. The trick I used was to zoom in the GPS (MemoryMap using CAA 1:250K charts) to maximum and start the climb when crossing a particular road.

Climbing to 300' and then simulating engine failure I couldn't make it back to the road without sinking through my 'hard deck'. I could do it with a 500' engine cut, so I guess this means that for an EFATO below 500' there’s no option but to land ahead. At 500' or above it might be possible to get back on to the field, probably with a down wind landing and only if the prospects of landing ahead were less inviting.

It was an interesting exercise, although I don't want to think about what would happen if a four second delay was introduced (to simulate the pilot’s recognition of the problem and to start to react).

Safe Flying,
Richard W.

This is exactly the problem between what you can do in a practice session and what is realistically obtainable when the totally unexpected silence occurs. The pitch down to the glide attitude should be automatic but what to do next will always take a few seconds to process. Interestingly NASA research shows that even professional pilots who fly everyday typically have a 3 to 5 second reaction time when given an unexpected emergency.

That is why I fear that pilots who have practiced the turn back and say "well I have repeatedly practiced the turnback and can do it every time from an altitude of 500 feet" have perhaps an unrealistic appreciation of how it would work for real. The other problem with practicing turn backs at altitude is the "ground rush" you will experience with the steeply banked very nose down attitude required for a successful turn back. This often results in inadvertently applying back stick and leads to a stall spin. The only way to get over this is to practice the manoever at actual low altitudes which is insanely risky.

Finally I think it is important to qualify the turnback. The aim of this manoever should not be to get back to the runway, it should be to reach any part of the flat, level and mostly unobstructed ground within the airport perimeter. If you can make the runway that is a total bonus.

But as I said in my opening post I strongly feel that for all but the most experienced pilots if a total engine failure occurs below 1000 feet AGL you are invariable going to better off gliding straight ahead and turning only to avoid major obstacles, and that is what I teach my PPL's.

It'll be different for different situations though so I don't see much value in practicing it. For noise abatement we try to turn ASAP once in the air...certainly below 500', and not far from the runway end. The result is that before 3-500' you have already turned 90 degrees ...but are heading away from the airfield . This could make it easier or harder to get back...Easier because you can turn less than 180 degrees and you are aiming at the airfield, but to line up you need to make another turn wasting more energy.

At these alts I'd either land ahead in one of the fields (depending on whether I have a head or tailwind now), or accept a landing anywhere on the airfield even if it is off runway.

Well, at risk of attracting another set of nanny flames...

DON'T DO THIS AT HOME. NOR IN AN AEROPLANE.

OK, that out of the way... I decided to see how much difference airspeed and bank angle make. This time I did it at altitude and measured time for a 360 turn rather than the teardrop manouevre, since all I was interested in was relative altitude loss.

The result was quite a surprise. Holding speed at the hairy edge of a stall does make a BIG difference. I flew each combination at least twice and the results were pretty consistent.

Bank Speed Altitude Loss
45 55 500
45 60 300
45 70 500
60 70 500+

At 55 knots in a 45 degree bank, the wing is most definitely partially stalled. There is a kind of buffet but it comes more from the nose bobbing up and down than from turbulence over the horizontal stab. What really surprised me is the big difference between flying on the brink of a stall, and 10 knots faster. Also that flying in a partial stall is no worse than flying 10 knots faster. That's reassuring from a safety pov.

The 60 degree result is clearly worse. It's also MUCH harder to fly, in my plane anyway - it's so nose heavy that precise speed control gets harder. If I wanted to get really repeatable results I'd have to practise some more, but it's clearly inferior both in terms of altitude loss and certainly in terms of safety, so there's not much point.

My methodology was: climb to altitude (3500'), pull power and slow down to desired speed, enter bank, fly a 360 degree turn holding bank angle and airspeed, roll level anticipating 360 degrees, check altitude. This was all in my 1980 TR182.

The result suggests that even 400' might be doable in my plane, IF you can hold airspeed/pitch precisely. At airports where landing off runway is not too bad (e.g. Livermore where there is a field at the end of the runway), it might be better than the alternative (though not actually at Livermore because the field is long). I don't think I'll be trying this for real close to the ground though.

DON'T DO THIS AT HOME.

OK, let the flames commence...

Well i'll flame you if you insist N, but for my money that was a really nicely constructed little research project that certainly gives extra confidence to one of Rogers' assertions.

G

Yep. Nicely done.

So essentially you confirmed the Rogers (?) paper that the lowest loss of altitude, assuming certain stability conditions, is achieved by making a 45-degree banked turn at the edge of the stall. Good.

GtE, I'm still interested in your stab at doing a paper when you remove those stability conditions, and analyze a proper EFATO situation. Mark1234 found out that the best results in that situation are achieved by initially setting a 60 degree bank, pulling to the stall, and reducing the bank angle as you fly the turn and the nose drops.

So am I, and it might be viable to open this up for wider participation.

I'm at the final stages of leading a multi-author paper analysing optimal stall recovery actions for single engined aeroplanes at the moment (5 of us as co-authors, and between us we've tested currently 12 aeroplane types, and that'll shortly be 15) - that should be done in the next couple of months and we can then agree the final wording and analysis and I can get it into the peer review.

We did this on the basis of preparing an outline test plan and analysis route, then opening the project up to participation. Several colleagues have done so - using their own flight resources, and it's been a lot of fun. Also, it's prepared conclusions that are based upon test results on 15 aircraft and brains of 5 variably experienced pilots. The best NASA have ever done on a similar project was I think 7 aeroplanes and 3 researchers.

[Hence our firmly unofficial lab slogan - "if it was easy, NASA would have done it already" !]


So, starting at Rogers' paper, I think one needs to construct algebraically a turnback that looks something like this:

(1) Engine failure, initial deceleration from Vy over a period of seconds while the pilot says "oh f********" slowly, then pitch to target turnback speed.
(2) Roll left to 45 degrees of bank whilst maintaining target turnback speed
(3) Change heading through 45 degrees.
(4) Roll right through 90 degrees to 45 degrees right bank
(5) Maintain 45 degrees right bank and target turnback speed until approaching runway centreline
(6) Reverse again to 45 degrees left bank to intercept centreline on runway track.
(7) Establish 1.3Vs and drop gear and flaps.

Each of those 7 is fairly easily modelled initially, although the model will certainly contain errors. Specifically:

(1) I have a model already for deceleration post engine failure that I published a few years ago and use for planning stall tests in certification programmes. There are standard values for reaction times, but this can also be tried in the simulator with a selection of pilots (in fact I think we might have that data already from another project).

(2) There are standard minimum requirements for achievable roll rate in the certification standards. If we assume that, it's a reasonable worst case.

(3) Standard flight mechanics

(4) As (2)

(5) As (3)

(6) Probably a bit of a guesstimate needed, but do-able.

(7) As (3)


We could then construct a test plan around that model which for a range of airframes at a safe altitude does the following:

(A) Confirm or deny 45 degrees of bank as best for height loss in the turn using a nominal fixed speed.

(B) Determine for that aircraft, the optimal speed for height loss in a turn at the optimum (hopefully 45 degrees) bank angle, and the height lost at that speed and bank angle.

(C) Validate the estimate for that aircraft of deceleration following an initial engine failure with height held for a pre-determined "Oh f**********" time.

(D) Determine height lost and time taken in accelerating to turnback speed following initial deceleration.

(E) Determine height lost and time taken to go from wings level at turnback speed to 1.3Vs with gear and flaps down.

(F) Finally and crucially, assess the actual handling difficulty in handling each part of the manoeuvre, and the manoeuvre overall, with a particular concentration on stall avoidance and runway centreline capture, using standard scales for pilot compensation and workload (Cooper Harper for the first, probably NASA-TLX for the second).


The analysis will take some time, the flying would probably take around 90-120 minutes on a single sortie for an experimental test pilot, nearer 180 minutes over 2-3 sorties for somebody not experienced in flight test ideally working with a flight test engineer in the other seat.

Standard GPS units would do a reasonable job of recording flight tracks, plus voice recorders (a dictaphone plus a tie-clip microphone stuck in the headset earpiece) can help a lot in gathering pilot comments, although I can bring a portable flight data recorder to the party.

If we could get the number of aeroplanes tested into double figures, back it up with some robust analysis, and include a few flying instructors in the authors list to make sure anything recommended is sensible and feasible. Well not only would that go well beyond Rogers' initial analysis, but we'd end up with something that could be a real benchmark in safety practice and training.

Worth doing I think. I think I'll do it and open it up to collaboration (and shared blame or glory as appropriate!); I can certainly bring three aeroplanes (a modern 4-seat low wing, a vintage high wing taildragger, a microlight) to the party and can think of a few fellow flying researchers who'd enjoy joining in. (Pilot_DAR, India-Mike, any interest in playing?)

G

Are you sure this would be the right approach? As far as I can see, during steps 1-4 and halfway through 5 you are still flying away from the runway.

Personally I would turn back towards the runway immediately (into the crosswind to minimize offset), and correct for the offset only at the end of the maneuver. So the teardrop shape is reversed.

Considering that you are going to lose altitude for sure during all this turning, I think that gives a better chance of making the threshold. Especially if the runway is short and you used the whole length during the take-off run. And in any case, I'd rather go off the far end of the runway at taxi speed, than undershooting the runway at flying speed.

Furthermore I think steps 1 and 2 should be combined. You drop the nose while rolling into the turn. So that by the time the nose is in the appropriate glide attitude, you are already established in the proper angle of bank and can start pitching for the turn straight away. (If you assume that this is essentially a ballistic maneuver it's relatively easy to model.)

In fact, Mark1234s experiment suggested that during this stage you can actually bank to 60 degrees, pull to the edge of the stall (not with 2G - it will be less but that's OK). Because you're not pulling 2G the nose will drop. At the time the nose has dropped to the glide attitude, you roll out to a bank angle that's sustainable, given your attitude, for the remainder of the turn. (Probably around 45 degrees.)

But I admit that that last maneuver will probably be an incredible bitch to model mathematically. And I doubt whether it would be the right technique to teach to low-time pilots in any case: If you don't roll back to a sustainable angle of bank at the appropriate time, you set yourself up for a major stall/spin accident. But that roll back might well be counter-intuitive to somebody without aerobatics/unusual attitudes experience.

I'm not a test pilot but I find this sort of stuff fascinating. I would not mind bringing the R2160 to the UK for a weekend so we can have a go in a basic aerobatics aircraft too - provided that somebody with some test flying experience is sitting next to me.

Genghis

Out of interest we teach turnbacks in the Grob 109B in the Air Cadet Organisation as follows:

Full engine failure - adopt glide attitude and 60kts, then assess height, up to 500' land ahead, above 500' turn back towards airfield. If landing area ahead is unsuitable you can turnback when above 300'.

Partial engine failure - if above 400' or able to climb to 400' then turn back to fly a mini-circuit to airfield, if not position to land ahead.

Even in a motorglider it needs a lot of height to be successful. Having spent about 800hrs teaching this stuff in the circuit to cadets, the wind and lift/sink conditions on the day have a massive influence and make the biggest difference to success.

Blagger - how are ACCGS teaching the Vigilant T1 turnback? - in terms of sequence of actions, headings and bank angles? I don't recall that we ever looked at it in the clearance programme at BDN, but arguably that is a CGS task anyhow.

Backpacker - you're on, although I also know one of the research Test Pilots at NLR quite well, and I imagine he'd be delighted to come and work with you if I had a chat with him.

G

Genghis - in principle yes. Currently at 0 Chipmunks though due to wind damage. The flight mechanics, I think, is probably only 50% of the turn back problem. The rest is operational, environmental and human factors. I've flown perhaps half a dozen turn backs in the last three years either in FI training or club standardization flights with our FIE. Although pretty straightforward to fly success is not determined exclusively by ability or aerodynamics.

But one has to start somewhere:)

Great I-M, and I agree - hence my references to using CHR and NASA-TLX as well as the flight mechanics tasks. Cooper Harper task construction will be a really major part of getting this right, and I can foresee a fairly robust round table on that subject.

Continued sympathies on the sad and undeserved death of the chippie. If we can meet at a suitable airfield or you're heading south, we could standardise by doing my Stinson together.

G

Genghis

Initial action lower nose to achieve 60kts

Assess RPM + height = make decision what to do

500ft + = turnback
300-500ft = turnback only if landing area ahead unsuitable
<300ft = land ahead

Turnback 180 deg onto a close-in downwind track (if you are going to turnback rather than going ahead)

Max 30 deg AoB (although use small AoB if a partial power loss mini circuit)

Aim to turn back again to land into wind, must start final turn by 250ft (300ft for trainees), but if height loss dictates you might have to accept a downwind landing.

In all cases level the wings by 100ft minimum and accept landing area ahead.

Approach attitude and speed all times when below 400ft.


Also, Tutor procedure is initiate not below 700ft, adopt glide speed + 5kts, turn back through 180 deg using max 45deg AoB (just back towards airfield), then further turn to land somewhere on airfield (or possibly straight downwind), wings must be level by 200' MSD.

I think you should model a 180deg turn onto a close-in downwind leg, you might then land straight downwind or turn again depending on height loss and landing areas available. Often an approach to a cross wind runway or clear surface ends up being the case.

Blagger (but anybody else flying Vigilants and Tutors...) You can't just turn 180 degrees - either you're going to:

(1) turn 45 left, turn 225 right,

(2) turn 225 right, turn 45 left

A turnback has always got to involve roughly 270 degrees of heading change.

Unless, I suppose, you can take advantage of a howling crosswind.


What you've described really seem to be outfield landings, somewhere on the airfield - rather than back onto the runway which is surely what a turnback is about. A turn onto a downwind leg is a glide circuit, not a turnback.

In my opinon :confused:

G

Genghis - A turnback (in the RAF anyway) is a manoeuvre to return to the airfield because the landing area options ahead are unsuitable. It is not soley focussed on a downwind landing on the runway. The airfield is a known environment, flat, with limited obstacles etc.. where you have better options for a forced landing than the terrain ahead. The subsequent landing could be anywhere on the airfield, it may be downwind on the runway but that would depend on a host of factors on the day. Most of the real SEP turnbacks I have known have resulted in a landing on the grass outside of the runway surface.

Ok, I can do the vintage taildragger and the instructor

I take your point, but a couple of quick calcs:

Typical light aeroplane, best glide 70 kn, so we fly the turnback at 75, using 45 degrees of bank, you get a 300 metre turn diameter.

Vigilant 60 knots, 30 degrees of bank, you get a 340 metre turn diameter.

Higher performance - try a Piper Arrow: 79kn best glide, so 84 turnback speed, 45 degrees of bank, gives 380m turn diameter.

To some extent, most aeroplanes at most airfields you are going have to turn beyond 180 degrees and then correct roughly back onto the runway heading. Apart from a big military airfields, most times and places, 300 metres likely to be well outside the airside perimeter.

So, I think that a 270 degree total heading change is realistic. This is what Rogers used in his paper.


My increasingly distant recollection of Bulldog, Tucano and Hawk practices is that turnbacks were always trained back onto the runway also.

G

This interests me. I'm happy to get involved. What I can offer has been PM'd to GtE, I'd enjoy getting involved!

4015

And there is the rub. At a moment of high stress induced by the engine failing you have to fly the aircraft right at the edge of its envelope at an altitude that leaves no margin for error.

If you are a proficient aerobatic pilot who practices regularly this is no big deal. However at the risk of sounding arrogant, if you are the average PPL with less than 250 hours total time who flies 15 to 20 hours a year, this is a recipe for a low altitude stall/spin accident, and those are almost invariably fatal, a sad fact confirmed by the accident statistics........

Hi Genghis, you're right - I accept that more than 180deg will generally be required in SEP types, I just think that a 270deg total is quite a demanding base requirement. What I'm trying to get at is that in real world situations I think the most likely scenario is that following an EFATO, the aircraft will be turned back towards the airfield and the eventual landing area will be somewhere across the airfield / runway departed on. For example, at Wellesbourne, a departure on Rwy 18, EFATO, turnback to right, would (at best) result in a landing somewhere on the grass to the left of Rwy 05. A likely heading of perhaps somewhere around 020? Perhaps a total turn of around 225deg? I just think that excessive low level turning would be overly demanding in real life and will make the model results very pessimistic about success.

Absolutely.

GENERAL WARNING to the readers of this thread.

Be advised that we are currently discussing theoretical scenarios at the edge of what an airplane is capable of doing. Unless you are extremely proficient in flying at the edge of the envelope, DO NOT try the techniques mentioned here in a for-real EFATO scenario.

If you want to practice these, do so at a safe height and with an instructor on board.

Which is why in a full research programme we need to include a reaction delay, and assess the ease of maintaining the best speed and bank angle, and ease of stall avoidance, and the overall pilot workload. With other things.

But, at a first look, what N did was show that Rogers' figure of 45 degrees bank angle for minimum height loss per degrees of turn seems to be correct. That in itself is a useful conclusion because it gives a bank angle that *probably* should be used by a pilot who is sharp enough and positioned well to fly a turnback. It is however only a part of a much bigger problem.

G

Happy to do my part for the R182. I'd expect the results for the non-retractable 182 to be substantially different (worse).

Some other thoughts/comments...

1. Re Backpacker's caveat/disclaimer: according to a thread over on the Cessna Pilot's Association, there are quite a lot of fatalities even WITH an instructor on board. So I think that should be "...with an instructor who has extensive experience with this manouevre". (I still don't really understand WHY - it requires precise flying but nothing extraordinary. Not something for a 100hr PPL but a CPL/FI with a few hundred hours should be able to do it safely).

2. I flew mine with a teardrop, i.e. initial turn of <135 degress heading back for the departure end of the runway, then another small (<45 deg) turn to align with the runway. The shape described by Genghis will leave you further from the runway end. Which would be good if you were a bit higher - when I tried it at 800' on a 4000' runway, I was way too far down the runway and did not land.

3. I'm a bit puzzled by the reaction time issue. Even 2.4S strikes me as a lot, and certainly 4S. If you're flying a Robinson 22 (heli) and the engine stops, you most certainly don't have that long before the rotor stalls and you plummet earthwards. But people do survive for-real engine failures in them. (Admittedly quite a few haven't). Part of it I think is being "wired for failure". (For example there's a spot where I know perfectly well that the engine will "fail" when I'm flying the heli, and my reactions are correspondingly good. The goal of course is to be that good no matter when). On take-off, good training is to be expecting it to suddenly get quieter. The one time it did happen to me, I was pointed back to the nearest airport in a LOT less than 4S. (It was only a brief engine hesitation and I was at altitude).

4. I respect Mark1234's experimental results, but I'd also say that for a repeatable, survivable technique, going initially to 60 degrees is (in my plane anyway) a LOT harder than 45. I was losing 10 knots on the initial roll then finding it hard not to pick up a 10 knot surplus (i.e. gaining 20 knots) as the nose dropped. It was quite uncomfortable - for someone with no acro experience or not *extremely* comfortable with the handling of the plane, it could be terrifying.

I am not sure I agree with you as to the value of another formal test program as quite a bit of research both theoretical and practical has already been done on this subject. The universal conclusion does seem to be 45 deg bank at min flying speed is the most efficient flight path.

An unexplored and IMO equally interesting scenario is the best way to do a turnback with say 1/3 available power, not enough to sustain level flight but enough to greatly reduce your sink rate. Off the top of my head my thought would be a teardrop with an initial 45 degree turn to one side followed by a 225 degree turn back to final with lower bank angle (30 deg ?) which would reduce the sink rate in the turn would be best. The 225 deg turn could be modified if you were too high (what I believe would be a likely outcome) by extending the flight path through the runway centre line and then turning back in.

Thoughts ?

GENERAL WARNING to the readers of this thread.

Be advised that we are currently discussing theoretical scenarios at the edge of what an airplane is capable of doing. Unless you are extremely proficient in flying at the edge of the envelope, DO NOT try the techniques mentioned here in a for-real EFATO (Engine Failure After Take-Off) scenario.

If you want to practice these, do so at a safe height and with an instructor on board.

BP - Very well said. I baled out of this thread a few days ago, and in my last post I advocated what you have just stated, but I am concerned about some of the points I am reading here. Every type, every situation, every type of weather, every type of pilot, what sort of day you are having/have had, all have a great bearing on 'the turnback', the decision, the 'emergency'. All of this debate is theoretical.

My contribution certainly isn't. My initial goal was to establish what *I* am capable of in *my* plane. Which I have now done. I agree that it is all type specific and pilot specific. I would not expect to get the same results in the Pitts or in a motor-glider, to take two extreme cases. I have also established experimentally, for my plane at least, that the Rogers analysis seems correct in practice.

And also had a couple of interesting and enjoyable flights. Not much theoretical about all that.