EFATO

[dkatwa]

Interesting article....
Safe Turnarounds - Plane & Pilot Magazine | PlaneAndPilotMag.com (http://www.planeandpilotmag.com/pilot-talk/more-pilot-talk/guest-speaker-safe-turnarounds.html)

How often do people here practice EFATO and what views do you have on the advice given in this link?

Also, what should you do, having commenced you TO roll, if you see the previous plane making a U-Turn and heading back to the runway....and you are doing 50kts and at the point of no return...

Update to post:
Thanks for the comments guys...I guess it is best to know your plane, maybe practicing steep turns at altitude without power, so as to determine how to do it (I trained to do steep turns with power) and also to determine height loss.
By the way, for some reason, the post automatically puts the full description of efat o, even though I assume everyone on here knows what it means...
anyway, thanks again for the comments
deepak

[RTN11]

An interesting read. A turn around is all well and good for an experienced pilot who knows his aircraft well, however the majority of private pilots are either students in training, where the safest option by far is to land straight ahead and take whats coming, or low hours pilots who do little more than the 12 hours a year to keep their licence.

The issue that isn't discussed in the article is that you would then be landing with a tail wind. So you take off into a nice 10-15kt headwind, the engine goes pop so you turn back and have to somehow get the thing down with 15kts behind you? how many people have trained for this? I've landed in a 7kt tailwind and that was bad enough, I've seen someone attempt to land in a 12kt tailwind, ended up 600 meters into an 800m strip, and just managed a go around at the last second.

If you're very current on type and pretty experienced there's no reason not to attempt this manouver if you think it is the best option at the time, but for the vast majority of people who fly light singles it would either lead to a stall/spin senario, or a duffed up tail wind landing - albeit that saving the aircraft at this point would be your last concern. Really, it depends where you are and what is available off the end of the runway. Most of the strips I have trained from have very suitable landing sites, so turning back would never be a consideration.

[Whopity]

Statistically it can be shown that most of those who attempt turn-backs, almost make it. The ones who walk away are those who land ahead. Accident statistics reveal a high proportion of home-builds are involved in turn-back accidents; no doubt the pilot is more concerned about the preservation of his engineering skills than surviving to repair it.

[Genghis the Engineer]

Personally I practice a PFL at-least once per month, although EFATOs a bit less often, mostly because my flying over the last few years has mostly been from quite busy airfields where it tends to get in everybody's way. That probably is a poor excuse and perhaps I should practice them more often.

However, I had reason to test my competence recently when I had a loss of power at about 300ft (not a complete failure) taking off into a 10-15 knot headwind. I am not generally a great fan of turnbacks, but with a strong headwind, combined with a reasonable amount of height to play with, and an aeroplane that I know well (100+ hours on the airframe) I called a pan and elected to turn back.

Despite sideslipping using full rudder and enough aileron to keep me on the centreline, it was clear that I was going to go through the far hedge. This was not a happy thought, but a happier thought was that the engine seemed to be behaving again, so I risked going around (keeping fields in gliding distance at all times I hasten to add) then at the suggestion of a very on the ball controller, turned back into the airfield to land on a disused crosswind runway.

(The wind was westerly, so I took off from a westerly runway, tried unsuccessfully to turn back onto a downwind easterly runway, then ended up turning left to land safely on a southerly runway - safely, albeit about on the aeroplane's crosswind limits).

That actually did make a really useful point to me about runway selection - there is at many airports a third option apart from a field or a turnback: that is a (perhaps disused, but who cares!) crosswind runway, requiring a roughly 270 degree heading change, but in a way that keeps you in gliding distance of the airfield throughout. In my "incident" I think although it all ended well, turning left to land crosswind on the northerly runway would have been a better option. But, prior to that I'd never considered it, and thus never briefed it. I do now!



Incidentally Whopity, I think that you may be partly incorrect in your last post. I've come across a lot of turnbacks where the aircraft was destroyed, but I can't think of any where anybody was killed (badly injured yes, killed no). I'm sure that there have been some fatals, but I think that the vast majority of turnbacks have been survivable, if not pretty.

Had my engine stopped completely, I'd have probably hit the far hedge doing about 20mph. The aeroplane would have been destroyed, but I think I'd have lived.

That said, I do agree with your assertion about homebuilts - it's one of the reasons why I think that few homebuilders are the right people to do the early test flying of their own aeroplanes. (I've had I think five engine failures testing homebuilts, although four of them I was able to re-start in the air, and the fifth I was on short finals so didn't bother. My experience of homebuilts is that if the engine is going to fail, it's generally at low speed/low power, not high power - stall testing, attempted spin entry, or a late approach have accounted for all of mine.)

G

[maxred]

Whilst we never say never,:) I would always land ahead. Genghis, there have been a number of fatalities in the States, where individuals have attempted a turn back. In my type, Beech Bonanza, a number of studies have been undertaken, (weather dependent), and it seems at least 1200 feet is necessary to even attempt the procedure.

In a twin, land ahead. Always.

The issue is that the aircraft turns into a glider, without the characteristics of one, and you are only going down:\

My view is that the insurance company can replace the aeroplane, a bit harder to replace the crew and passengers. I also think that the only reason one would turnback was to save the hull. Not worth it in my view.

[Genghis the Engineer]

Whilst we never say never, I would always land ahead. Genghis, there have been a number of fatalities in the States, where individuals have attempted a turn back. In my type, Beech Bonanza, a number of studies have been undertaken, (weather dependent), and it seems at least 1200 feet is necessary to even attempt the procedure.

As you say, 95% of the time I would land ahead also - I took the view at the time that I was in the 5% ! Given I'm intact, and the aeroplane re-useable (or will be once we've got the engine sorted), I stand by that.

I'm interested in your 1200ft figure for the Bonanza - I spent quite a lot of time "playing" with a Piper Warrior a few years ago, and came up with a figure of about 600ft. The Bonanza is a bit bigger and heavier than the PA28, but I'd not have thought sufficiently so to need to double the height.

G

[maxred]

Let me add to that. What Mr Church is advocating, the training and awareness, is all good. The ability to be confident in the machine you fly, at high angles of bank, and AOA, is superb. However, the basic PPL/NPPL course, UK, that omits even spin training awareness, leaves the majority of pilots (I would assume), without the basic skills set to look at the turn around procedure that is suggested.

Where he is coming from I would guess, is that this may/should be part of PPL training. The issue with this is that potentially a lot of trainees/instructors may not be comfortable with these manouveres at low altitude. It is different in practise higher up, but at 500-1000 feet it is a different story.

Everyone should try it though. Qualified instructor at their side of course. G - Jon Eckelbars - Flying the Beech Bonanza (ref).

[foxmoth]

There are one or two airfields where landing straight ahead is not a viable option once past the point you cannot land on the runway left (Southampton and bembridge spring to mind and I am sure other people can come up with a few). In this case a turn back should be preplanned and briefed including a look at all options such as a partial turn to land back on the airfield but maybe not all the way round to make the runway. This is a manoeuvre that, if you ARE going to use, needs to have been practised beforehand at height so you know just how fast and how low you need to get the nose and how much bank to use, also how far round you will get in the height available. I normally cover this on the UH Advanced PPL course, but as much to point out how difficult it is as to enable its use

[rans6andrew]

G the E,

one fairly recent fatal after turn back is G-BZVC, google will take you to the AAIB report. There are others but I can't keep all of them in my head.

Rans6.....

[RTN11]

Personally I practice a PFL at-least once per month, although EFATOs a bit less often, mostly because my flying over the last few years has mostly been from quite busy airfields where it tends to get in everybody's way.

I often practice the EFATO from the climb out of the PFL. keeps the student thinking, looking for a suitable landing site quickly and everything flowing on the ball. You should obviously still do some EFATO training at a field you regularly use just so you know your options if it happens for real.

[dont overfil]

The turnback is very type and pilot specific. At my local airfield I see flexwing pilots regularly practicing this manouevre successfully.

Last week for the first time I saw a fixed wing AC (with instructor on board) practice this. The issue with the larger fixed wing AC is the offset from the runway due to the turn radius.

D.O.

[Genghis the Engineer]

Fair point RTN - as do I, it's EFATOs at home base I'm sloppy about.

I feel a new thread coming on...

G

[deltahotel]

1. EFATO whether straight ahead or turnback - speed is life. If a turn back with (possibly) 45AoB, add some knots to the normal gliding speed (on the Bulldog with 75 kt glide I'd use 85 for a T/B). In the climb attitude the IAS will wash off really quickly if you don't get the nose down pronto, so: Select the gliding attitude, select yr landing field, select flaps/sideslip/manoeuvre to achive it.

2. Whatever you do should be preplanned and briefed. eg "up to 500' land ahead/L/R. after that t/b L/R etc etc" so it's already in yr head. I used to brief my students that once they'd started the upwind turn they could continue the turn to land on the airfield; before that land into wind on a suitable field.

3. There is no one size fits all to this. It will depend on experience level, currency, training, wind, terrain etc and (as above) the crucial thing is to make these decisions before you apply T/O power.

[Pilot DAR]

I suspect that it was this article which was the subject of a very similar thread last fall. I'm happy to see a more reserved not jumping on the bandwagon this time. As said, if well planned, and carefully executed, above a certain not published altitude, it can be done. I practiced it for hours, at a quiet runway with lots of options. The result of all of this practice was my forming the opinion that if for real, I would never consider it below 700 feet in a C 150, and even that, if I had planned my takeoff to accommodate it.

A friend of mine with more that 23000 hours had his homebuilt quit over the water 300 feet up after takeoff. He splashed it, and we got he and the plane back. Last year, different homebuilt, quit in the same place, he turned back, we got neither back.

You can develop a lot of drag really quickly in a turn. While test flying a Caravan with a draggy modification, I was practicing glides from the ideal spot in the downwind, and had trouble making it without adding some power.

My feeling about turn backs is similar to aerobatics, and a few other advanced maneuvers: If you have to ask if you can or should attempt it - you should not.

[Mark1234]

I have mixed feelings.. I largely agree with PilotDAR, and I also lament how little clue people really have about what their aeroplanes will do to get them out of a fix/how many 'wisdoms' aren't really true, or partially understood: e.g. That stalling in a turn will cause you to spin and die, or the need to increase speed in a turn, which really only is necessary if you're increasing load factor. A turn started at Vy attitude, and ended at best glide attitude isn't quite the same as a flat turn

I really like: My feeling about turn backs is similar to aerobatics, and a few other advanced maneuvers: If you have to ask if you can or should attempt it - you should not
.. but would probably add, do ask, do find someone to teach, and do go learn.

[tmmorris]

Bonanza could be as bad as 1200ft, I guess, for a safe turnback. The RAF include turnback in the pre-takeoff brief, with a specified altitude. I seem to recall (it's been a few years) that the Tutor for example is briefed as 'If the engine fails below 600ft I will land straight ahead. If the engine fails above 600ft I will consider turning back to the airfield to land.'

Note 'consider' i.e. it's a judgment call.

Tim

[peterh337]

There is a famous and very detailed analysis (http://jeremy.zawodny.com/flying/turnback.pdf) of this topic on the web.

A turnback requires certain conditions to be met, and they are best met if

- you identify the engine failure quickly
- you have a long runway
- you have a strong headwind (well, you won't be taking off with a tailwind ;) )
- you do a very sharp turn back (as much G as possible without stalling)
- you turn into wind

To a large degree, the decision whether to turn back, should the engine fail, can be made during the pre takeoff briefing, which a pilot should do even if flying on his own.

"In the event of a total loss of power, below 1000 feet, we will turn back, to the right, 60 degree bank angle".

On most commercial-sized runways (say 1500m+) it should be easy. But of course it depends when the engine fails. If it fails "too late" then you won't make it back to the runway no matter what :)

[maxred]

Bonanza could be as bad as 1200ft, I guess, for a safe turnback.

This was demonstrated as 'doable'.:\

It is all condition dependent, and no two incidents will be the same. But as stated, a whole host of 'ifs' come into the equation.

It has never happened to me, an EFATO, other than practice, and I equate it to an S turn display I used to do in a Chipmunk where I would fly runway length, at 50', full rpm, bank up 45 degrees at runway end, into a wing over, using the aeroplanes energy. I went over at about 450', and realigned, back down, to complete the manouver at the other end. Practised it a lot, however, it was all speed and energy mgt, and I always considered that completing this was akin to a turnback.

Reactions would have to be mighty quick to achieve a result, particulary at levels under 600'

[Genghis the Engineer]

There is a famous and very detailed analysis (http://jeremy.zawodny.com/flying/turnback.pdf) of this topic on the web.



Famous maybe, detailed fairly, correct debateable. I've spent quite a lot of time picking that paper apart - it's a good starting point, but no more than that. To be honest, as somebody who analyses a lot of aeronautical research papers I'd say it's pretty shallow and there's a lot more work that can be done.

G

[peterh337]

I tend to skip over the maths in these papers, partly because it is beyond me (I am an engineer :) )partly because it's obvious that the subject does not lend itself to precise analysis, partly because nobody but a programmed autopilot could carry out those maneuvers optimally, but the paper does illustrate the general idea which is that a turnback is possible and indeed under the right circumstances is very easy.

Whereas "everybody" says it will kill you, etc, etc.

The problem is that an EFATO at certain airports will give you no option but to go straight into the side of a building, which given the robustness of the average GA aircraft is a prob99 death. Not to mention the bad press if it is a convent/school/etc; more so if you do it in an N-reg ;)

[BackPacker]

(Note to the reader - this was originally posted in a different thread which was subsequently deleted by the OP. The mods were kind enough to retrieve it from the bit bucket and post it here, since it has some relevance here too. I later tweaked it a bit to better fit in here. The original context was a post where the author believed that with a bank angle of 45 degrees, the load factor automagically increases to 1.41, and thus the stall speed automagically by 20%.)

In a stable turn (non accelerating, non descending etc) the theory says that the load factor in a 45 degree turn is 1.4. But in the engine off scenario you are by definition not in a stable turn. You will be losing altitude for sure, and possibly bleeding speed as well, intended or not. Furthermore, the load vector angle is getting more and more horizontal, and this only increases when you go beyond the 45 degrees.

The result of that is that you can increase and decrease your load factor (by pulling more or less on the stick) a significant amount, but you will only increase or decrease the vertical component of lift by a tiny amount. With an increased load factor comes a higher stall speed, higher induced drag, but also a tighter turning radius. So pulling to the stall gives you the tightest turn, but also the least amount of time to "get it right". (And pull to the stall when the speed is too high/bank angle is too low will cause the aircraft to climb and thus bleed speed even more quickly.)

Making matters worse, without a lot of aerobatics experience (and the subsequent "feel" for the aircraft near the stall), without a G meter and with your head mostly outside the cockpit (which is a very good idea in those circumstances, don't get me wrong) how are you going to judge the load on your aircraft exactly? So how sure are you that your stall speed is indeed 61 knots? It probably could have been anywhere between 50 and 75.

I have not read that Rogers document intimately, but here's what I would do: Throw the aircraft in a 45-60 degree bank and then pull until the stall warner. Then play the stall warner and bank angle against each other so that I know I'm at the maximum turning rate while inevitably bleeding off the airspeed and the altitude. (In fact bleeding the altitude off in a controlled manner is the way to keep the airspeed up.)

But hey, I've got a lot of experience doing 75-degree banked turns (stable, thus 4G) at a mere 80 knots (sometimes even slower), with the stall warner blaring continuously, and playing the buffet. So playing bank angle against the stall buffet is not all that unusual for me.

Anyway, kudos for actually trying this, learning what your aircraft is capable of and how you actually achieve that performance. You now know you can do it from 500' up. If the EFATO ever happens for real, stick to what you've learned so far. Don't try it below 500' because some anonymous bloke on the internet told you it could possibly be done if you altered your technique. Land straight ahead.

[bookworm]

Famous maybe, detailed fairly, correct debateable. I've spent quite a lot of time picking that paper apart - it's a good starting point, but no more than that. To be honest, as somebody who analyses a lot of aeronautical research papers I'd say it's pretty shallow and there's a lot more work that can be done.

What don't you like in Rogers's paper? (I'm not taking sides one way or the other)

[Genghis the Engineer]

Much the same that the author does to start with - he is quite clear that it's a simplified model leading to a first approximation solution to the problem. He considers one speed margin above the stall, two bank angles and a single aeroplane only - and he hasn't validated his results with any flight test results.

I think if you asked David Rogers, he'd probably agree on all these points. What he did was a very good first stab at a mathematical solution to the problem and demonstrated that the maths, and the historical evidence are broadly consistent - to whit, turnbacks can be possible.

However, it's a real shame in my opinion that 18 years later, that good start by Dr Rogers hasn't been actively followed up and published. Given time, I'd like to have a go at it myself, and may yet do so.

G

[bookworm]

That makes sense. I think the key learnings from the maths are that a 45 degree bank is optimal for height loss per unit angle turned, and that there is no optimum speed -- it should be as low as possible. It then becomes a question of practicality and pilot skill.

When I did some simple flight tests at altitude in a Mooney 201 (probably 15 years ago), I remember some insights:

* with a decent aural stall warner, flying the aircraft at the edge of the stall-warner onset is fairly easy -- relax pressure if you hear it

* while the height loss in the turn is fairly low (as Rogers predicts), you come out of the turn at low speed and at high rate of descent -- that requires you to accelerate to make a normal landing, which takes time and height

* in the analysis of where you end up, a lot depends on the difference between climb gradient and glide ratio -- in a powerful aircraft, it's much easier to get back to the airfield, while in a poorer performer (or at higher weights, density altitude), you'll end up beyond the upwind threshold.

[Genghis the Engineer]

I don't read that from the paper - he shows that 45 degrees is better than 35 degrees, but doesn't really explore different speeds, or any other bank angles - so it hasn't got as far as a general case.

Your conclusions from your own testing however Bookworm, are pretty much the same as my conclusions in a PA28-161 and a Thruster TST about half a dozen years ago.

G

[bookworm]

I don't read that from the paper - he shows that 45 degrees is better than 35 degrees, but doesn't really explore different speeds, or any other bank angles - so it hasn't got as far as a general case.

Oh, I think he does. At the end of the section "the optimum bank angle" he shows that the rate of height loss per unit angle turned (in the steady state case) is proportional to 1/sin(2*bank), which is minimised at 45 degrees. The only reason he shows 35 degrees is because it's Eckalbar's recommendation.

Of course one could argue that the true optimum comes from a non-steady state turn, but I don't think you'd do much better.

[Mark1234]

The other massive factor is how much runway you have left when you get airborne - it effectively offsets the glide path 'under' the climb path. For that reason alone I don't think you can come up with a single height for a turnback, even on one aircraft. There's a minimum to make the turn sure, but after that it's a question of circumstances.

[Genghis the Engineer]

Oh, I think he does. At the end of the section "the optimum bank angle" he shows that the rate of height loss per unit angle turned (in the steady state case) is proportional to 1/sin(2*bank), which is minimised at 45 degrees. The only reason he shows 35 degrees is because it's Eckalbar's recommendation.

Of course one could argue that the true optimum comes from a non-steady state turn, but I don't think you'd do much better.

I missed that - fair point, although still not validated with any experimental data.

I think that I may feel the need to go and have a play!

G

[dkatwa]

I am grateful for the replies here. I have a PPL although not flown since I got the licence in June 2010...long story...but hope to restart this year.....

In a strong cross wind, one would have to turn into wind if attempting a return to runway.....thing is, will turning into wind reduce the lost of height in any way (quicker airflow over the wings, providing vital lift)?

Maybe I should know the answer to this but I have been out of the aviation loop recently....apologies in advance....

[BackPacker]

dkatwa, as soon as your wheels have left the ground, you're flying inside a block of (moving) air. Inside this block, it really doesn't matter which way you turn. Aerodynamically speaking it's all the same.

The turn into the wind is not to add airflow to the wings or something like that, but simply so that when you come out of the turn, you are still very close to the runway, instead of blown away for miles.

[mm_flynn]

I am grateful for the replies here. I have a PPL although not flown since I got the licence in June 2010...long story...but hope to restart this year.....

In a strong cross wind, one would have to turn into wind if attempting a return to runway.....thing is, will turning into wind reduce the lost of height in any way (quicker airflow over the wings, providing vital lift)?

Maybe I should know the answer to this but I have been out of the aviation loop recently....apologies in advance....

Right answer ... Fundamentally wrong logic.

The wind (assuming it is constant) has no effect on the flight dynamics - none!

However, if you draw the basic turn back with no wind (about 270 degrees of turn - 180 back, 45 to track towards the airport, 45 to align with the runway) and then redraw it off setting each position a bit more downwind to reflect the cumulative displacement from the cross wind, you will see the final 45 degrees and then the turn back on course will be substantially reduced. So less turning time and less distance travelled means less height lost.

[Big Pistons Forever]

As an instructor I am hard over on this one. Unless you fly virtually every day and practice this manoever often, a situation that I would argue will never apply, to virtually everyone reading this forum, Then I think one should never attempt a turn back below 1000 feet AGL.

What should be is that every pilot is good enough to a immediately assess the the nature of the emergency, because remember you may only have a partial engine failure (see Gengis post for what a can of worms that can be), then immediately execute a steep low altitude turn at just above stall speed.

What IS however is an accident record where many turnbacks end in fatal crashes. Survivable crashes are ones where you hit the ground wings level in a level flight or nose up attitude. The killer crashes are low altitude stall spins or hitting the ground in a very nose low attitude, precisely what will happen if you screw up the turn back.

I think it is also important to point out that the most important action after an EFATO is to immediately lower the nose to the glide attitude.
An EFATO with the aircraft nose at the Vy attitude will loose airspeed very quickly unless the nose is lowered as soon as the engine fails. I personally know of a fatal accident where the aircraft stalled right after the EFATO because the pilot froze and did not lower the nose in time.

So I teach Vy climb to 1000 AGL as altitude is your friend so you want to get to an altitude where you have options as quickly as possible, and in the event of an engine failure below 1000, it is nose down to the glide and only turning enough to avoid major obstacles.

I also insist that before every takeoff the student reviews the actions for an engine failure during the takeoff and after takeoff including touching the relevant controls. The EFATO portion starts with him/her physically moving the control wheel firmly forward. After doing this brief 30 or 40 times the actions become automatic and that I think is what will save your bacon if you are unfortunate enough to have an EFATO, not some hero pilot split arse low level steep turn.....

Finally one area where the flight school IMO do not place enough emphasis is for an engine failure on the takeoff roll is to immediately fully close the throttle. Again I have personal knowledge of an accident where an airplane was destroyed and the occupants injured because the pilot failed to accomplish this simple action when the engine died on the takeoff roll.

[Genghis the Engineer]

As an instructor ....

... the student reviews .... including touching the relevant controls. The EFATO portion starts with him/her physically moving the control wheel firmly forward. ..... for an engine failure on the takeoff roll is to immediately fully close the throttle.

You know BPA, I like to think that I can fly, and I'm starting to get the hang of teaching those aspects of flying that I'm qualified to teach.

I think you've described two things there that I have seldom, possibly never, seen briefed. It took about 10 seconds of reading your post to decide that you've just shared something really really valuable that will now be a permanent fixture in my flying and teaching.

:D Thank you very much. :D

G

[abgd]

Big Pistons: I don't think I would have thought to close the throttle if on the ground. Thanks for that.

[Jan Olieslagers]

one should never attempt a turn back below 1000 feet AGL

Far from feeling qualified to argue, I would humbly ask for a bit of clarification: would the 1000' minimum equally apply to slower planes and to the faster? 't Would seem to me that a slower plane - i.e. with lower stall speeds - could try it from less altitude? AIUI, the 1000' was for the average Cessna or PA28, but perhaps a microlight or LSA could make do with less?

[Big Pistons Forever]

Far from feeling qualified to argue, I would humbly ask for a bit of clarification: would the 1000' minimum equally apply to slower planes and to the faster? 't Would seem to me that a slower plane - i.e. with lower stall speeds - could try it from less altitude? AIUI, the 1000' was for the average Cessna or PA28, but perhaps a microlight or LSA could make do with less?

The 1000 foot restriction is meant as a rule of thumb for the typical 2 or 4 place fixed gear light aircraft you would normally find available for rent/training or commonly owned by a PPL.

I have never flown a AULA/LSA/Microlight so I am not qualified to offer advice as to what would be the best course of action for the EFATO emergency in this class of aircraft

[Big Pistons Forever]

You know BPA, I like to think that I can fly, and I'm starting to get the hang of teaching those aspects of flying that I'm qualified to teach.

I think you've described two things there that I have seldom, possibly never, seen briefed. It took about 10 seconds of reading your post to decide that you've just shared something really really valuable that will now be a permanent fixture in my flying and teaching.

:D Thank you very much. :D

G

Thanks for the kind words. I would like to add as food for thought that I have found that practicing the transition from power in climb to power off glide is a worthwhile exercise. At altitude in the practice area simple establish a normal full power Vy climb and when the aircraft is stabilized smoothly but quickly reduce the power to idle. My experience has been that most pilots are surprised that it can be initially a bit difficult to make a smooth transition to a stable glide attitude because of the trim change caused by the lack of power and the fact that the relatively large nose down pitching motion is required. It only takes a few minutes to demonstrate and like I said I think it is worth practicing every once in a while.

Another point I alluded to but IMO bears emphasizing is that altitude = options. I see a lot of pilots make very shallow climbs immediately after takeoff. This prolongs the exposure to the low altitude EFATO environment and so for that reason the profile I teach, and always fly myself, is Vy to 1000 feet AGL.

[BackPacker]

would the 1000' minimum equally apply to slower planes and to the faster?

Jan, just like Mark1234 mentioned a few posts back, there's no hard and fast rule about this. Sure, you can probably accomplish a 180 degree turnback in 1000' even if you're not applying perfect technique (as long as you bank sufficiently - there is no room for a rate-1 turn or something similar).

But the emergency is not over once you've made the turn. You were climbing out at some angle at Vy from the threshold, now you're still as far away from the threshold as you were when you started the turn, but you lost a few hundred feet and you have no engine power. Is your glide angle sufficient to reach the threshold?

I have seen a Pitts Special climbing away after departure at an angle of 45 degrees. Now the Pitts is reputedly not a good glider, but it should be able to glide at significantly less than 45 degrees nose down. On the other hand, our DA40 with the 135 HP Thielert was normally just able to clear the trees at the far end of a (long) runway, if fully loaded, and would never be able to glide back to the field after a straight out departure. Even if you climbed to 10.000' and then turned, you would not be able to make the runway. (Despite the sailplane heritage, the DA40 still only has a glide angle of 1 in 8, and that's about equal to its climb angle.)

And another factor is how much runway you still have available ahead of you, when you rotate during the take-off. If that is significant then that bit of runway may still be reachable from the glide, whereas your original rotation point may not be reachable.

(And to put a bit of perspective to the debate, and how dependent it is on airplane capabilities and circumstances: In gliding we fly a full (although tight) circuit when the winch cable breaks at 300' or above. Yes, you read that correctly. A full circuit, with four 90 degree turns, to a normal landing in the normal landing area next to the take-off area, from 300 feet. But a winch launch cable break happens by definition *above* the airfield, not beyond the threshold, and any reasonably modern glider will easily beat a 1:30 glide angle.)

[flyinkiwi]

It was a nil wind day, I had given the engine a thorough runup and there was nothing suspicious detected. We had just taken off and at about 100' the engine coughed. At 250' it coughed again, and then one of the magneto's failed. The engine cowling started vibrating quite badly so I smoothly reduced power and the shaking stopped at about 75% throttle. Even on one mag and partial throttle the plane was still climbing so I chose to return to the field instead of landing ahead. Had the engine quit at any time during the reversal turn I was well within gliding distance of a runway (thank goodness I was in a 172M and not the Arrow) and in the end I circled and put her down on a crossing runway.

I realize I didn't exactly do things by the book, so please, follow the advice of the vastly more experienced pilots and instructors lurking around rather than me.

[Big Pistons Forever]

It was a nil wind day, I had given the engine a thorough runup and there was nothing suspicious detected. We had just taken off and at about 100' the engine coughed. At 250' it coughed again, and then one of the magneto's failed. The engine cowling started vibrating quite badly so I smoothly reduced power and the shaking stopped at about 75% throttle. Even on one mag and partial throttle the plane was still climbing so I chose to return to the field instead of landing ahead. Had the engine quit at any time during the reversal turn I was well within gliding distance of a runway (thank goodness I was in a 172M and not the Arrow) and in the end I circled and put her down on a crossing runway.

I realize I didn't exactly do things by the book, so please, follow the advice of the vastly more experienced pilots and instructors lurking around rather than me.

I am a bit confused by your comment that "I didn't do everything according to the book". If the aircraft has enough power to maintain level flight or in your case still manage to climb then it by definition has not suffered an "engine failure" and so the "turn back" in the context of this thread does not apply.

Your decision to immediately return to the field and to do so in such away as to maximize your chance of landing back on the runway in case the engine suffered any further loss of power, strikes me as exactly "doing it by the book".

All the heated arguments of exactly what bank angle to use for a turn back and lengthy dissertations on changes in AOA, accelerating vs non accelerating turns, variations in the vertical component of lift etc etc, obscure the fact that what happened to you is a lot more common than the sudden complete engine failure at low altitude and that every partial engine failure will have different consequences and so ultimately making sure you fly the aircraft first and then picking a conservative course of action that will give you options should the situation deteriorate further is the best one can do....but I guess that is not as sexy as discussing hero pilot moves......

As an aside one thing that never seems to get talked about in flight training is knowing the minimum power setting to maintain level flight. In the average Cessna it is around 1900 RPM. In the event of a partial engine failure this is a good number to know. If the power winds back but you are still getting a solid
1900 RPM you will stay in the air, at least for now. Less than that and you had better be planning your forced approach.

[Big Pistons Forever]

(And to put a bit of perspective to the debate, and how dependent it is on airplane capabilities and circumstances: In gliding we fly a full (although tight) circuit when the winch cable breaks at 300' or above. Yes, you read that correctly. A full circuit, with four 90 degree turns, to a normal landing in the normal landing area next to the take-off area, from 300 feet. But a winch launch cable break happens by definition *above* the airfield, not beyond the threshold, and any reasonably modern glider will easily beat a 1:30 glide angle.)

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.

[Piper.Classique]

The wind (assuming it is constant) has no effect on the flight dynamics - none!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 :(

[foxmoth]

So I teach Vy climb to 1000 AGL as altitude is your friend so you want to get to an altitude where you have options as quickly as possible, and in the event of an engine failure below 1000, it is nose down to the glide and only turning enough to avoid major obstacles.

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?

[BackPacker]

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."

[Big Pistons Forever]

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?

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.

[BackPacker]

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.

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%.

[Big Pistons Forever]

.

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.
.

True; which is why I made the comment

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 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.

[n5296s]

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!

[Big Pistons Forever]

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.

[foxmoth]

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

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!

[n5296s]

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.

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.

[Big Pistons Forever]

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!



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:

[Maoraigh1]

However in every case you can make any aircraft land by smashing it into the ground at your chosen point.

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

[Big Pistons Forever]

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"................

[Whiskey Kilo Wanderer]

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.

[Big Pistons Forever]

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.

[englishal]

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.

[n5296s]

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...

[Genghis the Engineer]

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

[BackPacker]

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.

[Genghis the Engineer]

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

[BackPacker]

(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

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.

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?)

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.

[blagger]

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.

[Genghis the Engineer]

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

['India-Mike]

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:)

[Genghis the Engineer]

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

[blagger]

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.

[Genghis the Engineer]

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

[blagger]

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.

[Piper.Classique]

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.


Ok, I can do the vintage taildragger and the instructor

[Genghis the Engineer]

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.

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

[4015]

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

[Big Pistons Forever]

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.


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........

[blagger]

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.

[BackPacker]

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.

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.

[Genghis the Engineer]

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........

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

[n5296s]

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.

[Big Pistons Forever]

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

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 ?

[maxred]

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.

[n5296s]

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.

[what next]

All of this debate is theoretical.

I took the trouble to read my way through the whole thread (which is very interesting b.t.w.!) and come to the same conclusion: A purely academical exercise.

Almost impossible to teach (at least to PPL students or low-hour private pilots) and entirely dependent on the nerve strength of both the instructor and the student. Doing 45+ degree banked turns below 500ft will scare the hell out most pilots (instructors included) even if a well researched paper predicts a favorable outcome of the maneuver. Training this procedure at a safe altitude (or in a simulator) will not help at all, because all the human factors that make it so difficult in real life will be taken away.

I would rather opt for a software solution (like an app for a smartphone or iPad) that will emit a signal once a speed/position/altitude has been reached, from which an averagely skilled and trained pilot should be able to fly a successful return maneuver within the normal operating envelope of his aeroplane (best glide speed +/- 10kt, turns with no more than 30 degrees of bank, ample reaction times). If your device hasn't beeped yet, you glide to a landing straight ahead, if you heard it beep, you are safe to turn back.

[24Carrot]

n5296s, the input was very useful. Though in real life I guess the prop might be windmilling?

Thanks also to Big Pistons Forever, I have seldom seen such concentrated common sense, especially "under fire".

It seems to me, (by no means a "Sky God"), that I wouldn't even consider the turn back under 500 ft in a C172 or similar, by which time I'm typically turning onto cross-wind, or even earlier for noise abatement etc, as somebody else posted.

So could we perhaps tone down the "Health and Safety" warnings a little if we re-cast the question as "what best to do with Engine Failure On Crosswind?" (EFOC?)

What we generally need to know is how much turning an average pilot can squeeze into any given height, especially if much draggier than usual because of a windmilling prop.

Just my 2c.

[Genghis the Engineer]

I would rather opt for a software solution (like an app for a smartphone or iPad) that will emit a signal once a speed/position/altitude has been reached, from which an averagely skilled and trained pilot should be able to fly a successful return maneuver within the normal operating envelope of his aeroplane (best glide speed +/- 10kt, turns with no more than 30 degrees of bank, ample reaction times). If your device hasn't beeped yet, you glide to a landing straight ahead, if you heard it beep, you are safe to turn back.

I suspect that may be possible, or (me being a bit of a technological luddite) possibly a graph for any given aeroplane which can be referred to before take-off and says for runway length X and headwind Y in this aeroplane, below height Z you will not get away with a turnback, but above that you have a fighting chance if flown well enough.

There are four main reasons to do the research in my opinion, which for me are:-

(1) It'll be fun and interesting

(2) It'll give people who might consider a turnback a clear indicator of when NOT to consider it.

(3) There are lots of runways without a land ahead option. Runway 23 at Lee on Solent, runway 19 at Oban, runway 29 at Sheffield City, Grand Canyon Airport in Arizona, plenty of small island airports or mountain airports around the world. Nobody's going to close these runways - so if they're going to get used, perhaps pilots flying there should have some material they can use for training and practicing turnbacks.

(4) See (1).

G

[Big Pistons Forever]

n5296s, the input was very useful. Though in real life I guess the prop might be windmilling?

Thanks also to Big Pistons Forever, I have seldom seen such concentrated common sense, especially "under fire".

It seems to me, (by no means a "Sky God"), that I wouldn't even consider the turn back under 500 ft in a C172 or similar, by which time I'm typically turning onto cross-wind, or even earlier for noise abatement etc, as somebody else posted.

So could we perhaps tone down the "Health and Safety" warnings a little if we re-cast the question as "what best to do with Engine Failure On Crosswind?" (EFOC?)

What we generally need to know is how much turning an average pilot can squeeze into any given height, especially if much draggier than usual because of a windmilling prop.

Just my 2c.

If you are on a crosswind leg and the engine fails you are probably at or above 500 feet AGL and a 90 degree turn with 30 degrees of bank to the nearest flat surface within the aerodrome boundaries would IMO be completely doable for the average pilot and is in fact what I tell my students to do for this particular situation.

[n5296s]

Though in real life I guess the prop might be windmilling
True. But if you had the presence of mind it would be windmilling in coarse pitch (assuming a constant speed prop). I'd LIKE to compare the difference between a prop windmiling in coarse pitch and one under idle power in fine pitch, but that's beyond my nerve/stupidity. I always do power-off exercises in fine pitch hoping that the two will balance out, more or less.

Of course if you have a fixed prop this is all irrelevant.

[Big Pistons Forever]

True. But if you had the presence of mind it would be windmilling in coarse pitch (assuming a constant speed prop). I'd LIKE to compare the difference between a prop windmiling in coarse pitch and one under idle power in fine pitch, but that's beyond my nerve/stupidity. I always do power-off exercises in fine pitch hoping that the two will balance out, more or less.

Of course if you have a fixed prop this is all irrelevant.

Pulling the prop to full decrease makes a very significant impact on the glide performance and should be part of the shutdown check on every aircraft with a constant speed prop.

[englishal]

Interesting experiments.......I might go and try some of my own.

I read a very good article once about EFATO. It was written by some really experienced aerobatic pilot (I forget where I read it, US AOPA I think), and the best bit of advice he gave was "push until the ground fills a two thirds of your windscreen". This is very good advice, as we had an EFATO recently from our airfield (below 500') and as is common the aeroplane stalled. Luckily for the pilot he was not that high but he still managed to end up mushing down and cartwheeling along the airfield as the wing dropped and "landed" first, and he was trapped underneath in a fuel loaded smashed up aeroplane. Hurt but not too seriously but covered from head to toe in avgas.

My buddy was there and sent me some pics, very scary stuff. Luckily all his holes didn't line up that day.....a bit higher, a bit faster, and I expect there would have been a different result.

Whatever you do, keep flying :ok:

[maxred]

I suspect that may be possible, or (me being a bit of a technological luddite) possibly a graph for any given aeroplane which can be referred to before take-off and says for runway length X and headwind Y in this aeroplane, below height Z you will not get away with a turnback, but above that you have a fighting chance if flown well enough.

G - Yes a good theoretical experiment, that may yield some interesting and anecdotal information reference said aeroplane. But that is the point, it will be that particular aeroplane, with a particular weight, with a particular configuration. The concern Backpacker was alluding to, correct me if I am wrong BP, was that someone MAY, read this, and think, I am going to try that next time I take off in my PA28 or whatever, and guess what - the 45 degree bank angle et al might not work.

This is Bonanza specific. You fly landing approaches at 1.3 times stall speed (good compromise between low speed and safety margin above stall. Therefore in a 45 degree bank angle, multiply the stall speed by 1.3 and you get a turnback speed with same safety margin for stall - app Vy.

Also, which I do not think anyone has pointed out yet, high density altitude airfields make this almost impossible because the climb gradient is flatter, and high weight also reduces climb gradient which in turn raises your stall speed, and turn speed, which increases your turn radius and decrease your rate off turn.

Let your watchward be take care.

[BackPacker]

Well, I guess the process is no different than trying to create a graph for, let's say, landing distance. You first figure out what the proper and achievable technique is. You then figure out the baseline results for ISA conditions, MTOW, nil wind etc. And from there you start figuring out what sort of difference different conditions make.

Having seen, and worked with the landing distance graphs in the PA28 POH, I am convinced that it should not be beyond the average PPL to use a more or less similar multi-step graph to figure out the turnback height. But you are right: That graph will be aircraft-specific. Although the research may yield some generic results that would make it easy to adapt the graphs to different aircraft.

And I would not be surprised if the eventual graph contained a "here be dragons" area or something like that. Meaning: Do not go here or there's absolutely no way out. Don't single engine helicopters not have a similar graph for that part of the flight envelope where you cannot survive an engine out (because you're too low and slow for autorotation, but high enough to end up dead)? Pilot training should then simply be about risk mitigation and avoidance of those circumstances.

[Big Pistons Forever]

Well, I guess the process is no different than trying to create a graph for, let's say, landing distance. You first figure out what the proper and achievable technique is. You then figure out the baseline results for ISA conditions, MTOW, nil wind etc. And from there you start figuring out what sort of difference different conditions make.

Having seen, and worked with the landing distance graphs in the PA28 POH, I am convinced that it should not be beyond the average PPL to use a more or less similar multi-step graph to figure out the turnback height. But you are right: That graph will be aircraft-specific. Although the research may yield some generic results that would make it easy to adapt the graphs to different aircraft.

And I would not be surprised if the eventual graph contained a "here be dragons" area or something like that. Meaning: Do not go here or there's absolutely no way out. Don't single engine helicopters not have a similar graph for that part of the flight envelope where you cannot survive an engine out (because you're too low and slow for autorotation, but high enough to end up dead)? Pilot training should then simply be about risk mitigation and avoidance of those circumstances.

The easiest way to mitigate the risk is not to turn back below 1000 feet AGL a simple easy number to remember and conservative enough to work pretty much all the time.

Risk mitigation is fine but if you want to be holistics about mitigating the risk then you should mitigate the risks for the whole flight. Instead of obsessing about the Turn back between 400 feet and 1000 feet I think the time and energy should be spent on other areas which experience has shown is much more likely to present a risk to a flight like

-practicing the very late overshoot, or

-short field takeoff and landings including a practical stratagy for determining a go no go point, or

-practicing the 180 degree turn on instruments that you would use on an inadvertant IMC encounter, or

-determinimg exactly what your cruise fuel burn with a series of planned test flights etc etc..........

[n5296s]

obsessing about the Turn back
Well, I'm not sure I'd call 2 hours of flying, when I just felt like flying and din't have anything very specific to do, exactly OBSESSING. Just speaking for myself here. I do do all those other things too...
Don't single engine helicopters not have a similar graph for that part of the flight envelope where you cannot survive an engine out
Indeed. It's generally called the Dead Man Zone, just in case the meaning isn't obvious. But, unlike taking off in an aeroplane, it is avoidable. You don't HAVE to hover at 200'. (Well, actually for quite a lot of heli missions, e.g. long-line work, you do, but that's too bad). Whereas you do HAVE to be at 200' and Vy in an aeroplane, if you want to fly it at all.

Different topic: over on the Cessna Pilots Association, there was some discussion about how trim plays into all this. As in, you're 15-20 degrees nose up at Vy, and the engine stops. Suppose you just let go of all the controls. What happens? Some time soon, the plane will be flying at Vy (assuming you were trimmed in the first place). It may have lost a bit of altitude getting there, but it won't be stalled. I'll give this a try next time I get a chance.

I still don't really see how you get a real developed stall doing this, except maybe trying to arrest the descent close to the runway. I was actually surprised at how benign things were pulling back below stall speed in a descending turn. But clearly people do :-(

[BackPacker]

Different topic: over on the Cessna Pilots Association, there was some discussion about how trim plays into all this. As in, you're 15-20 degrees nose up at Vy, and the engine stops. Suppose you just let go of all the controls. What happens? Some time soon, the plane will be flying at Vy (assuming you were trimmed in the first place). It may have lost a bit of altitude getting there, but it won't be stalled. I'll give this a try next time I get a chance.

Be sure to let us know the results.

I see two issues here though.

First is that people are taught to fly by attitude, and by looking out the window, not by chasing the needles. Especially early in their career, VFR. So they will not let go of the controls but intuitively try to keep the nose up, until they realize what happens. But by then it may be too late.:=

Second is that even if you let go of the controls, there will be a lot of inertia in the aircraft, and it will take a while to settle in a stable glide (again at Vy, assuming it was trimmed for Vy in the first place). During that period there may well be speed excursions below Vy, and even below Vs, but these, I would imagine, will be at a load factor lower than 1G. I would be very, very surprised if the aircraft were actually to stall in this scenario.

Anyway, the point being that the oscillations before reaching a stable Vy descent may take too long. If you fly the maneuver instead of letting go of the controls you reach that stable state much earlier, and have much more opportunity (read height) to figure out what to do next (whatever that may be).

[BackPacker]

Okay, I've got the plane reserved for Saturday morning. The weather looks good and I'm keen to explore some of the EFATO turnback issues discussed here.

Please critique my "test plan".

Key numbers from the POH:
Vs = 63 knots (at MTOW)
Vbg = 78 knots (at MTOW) - supposedly yields a 1 in 8.7 glide ratio, and a V/S of ~900 ft/min (to confirm)

Vs in a 45 degree stable descending turn is thus theoretically ~75 knots. Close enough to Vbg to not need to explore the difference in performance between pulling to the stall at 45 degrees, and flying Vbg at 45 degrees. In fact (but to be confirmed) I expect the stall warner to sound continuously, with noticeable buffet, in a 45 degree Vbg stable turn.


Preliminary actions:

HASELL

(i) From height, establish the aircraft in a Vbg stable, trimmed descent. Mark attitude with some sticky tape on the canopy. Write down/time V/S.
(ii) From height, establish the aircraft in a Vbg stable, trimmed descent at 45 degree bank left and right. Mark attitude again with some sticky tape. Write down/time V/S.
(iii) From height, establish the aircraft in a Vbg stable, trimmed descent with the mixture closed. Write down/time V/S.

(i) and (ii) are so that the proper attitude for the subsequent tests can be set quickly. (iii) is to provide data on the difference between throttle closed and mixture closed (prop windmilling), so that all subsequent data points can be corrected for that.

Test items:

All items start from a stable, properly trimmed Vy climb along a line feature, into the wind as far as possible. When passing through a certain safe height (3000' most likely, weather permitting) I'm going to pull the power and:

a. Hold the nose up to see how long it takes for the aircraft to stall. Then recover the stall and see how much time/altitude I lose before in a stable Vbg glide.
b. Hold the stick in the same position, furthermore as in (a).
c. Completely release the stick, let the aircraft sort itself out, furthermore as in (a).
d. Fly the aircraft in a half-G pushover, furthermore as in (a).
e. Fly the aircraft in a ballistic arc (zero G), furthermore as in (a).

(a)-(e) are essentially to see how much "oh ****" time I've got, and how important ingrained reflexes are. If, for instance, (a) delivers the same as (d)/(e) (which I don't expect), the "oh ****" factor isn't all that important.

Subsequent tests include one second of "oh ****" time after closing the throttle, then:

f. Establish Vbg according to the best technique from (a)-(e), then turn into the crosswind 225 degrees at 45 degree bank, turn the other way 45 degrees at 45 degree bank.
g. Same as (e) but with 60 degree bank
h. Same as (e) but with 30 degree bank

(g) and (h) essentially to confirm Rogers

i. Like (f) but start with a left turn 45 degrees away from the crosswind, then turn 225 degrees into the crosswind (teardrop thus reversed). Altitude lost should be the same as (f), but you never know.

j. Like (f) but this time roll into a 45 degree bank while pushing the nose down (at half or zero G as appropriate), ready to pull as soon as the Vbg attitude has been set.

k. Like (f) but use the Mark1234 technique of immediately rolling to 60 degrees bank, pull to the stall warner while the nose drops, play angle of bank against stall once the nose is at the Vbg attitude.

At the end of all items a-k, write down altitude lost.

Further things to note: QNH, OAT, actual weight, actual wind. I will also run an outdoor-type GPS which has track recording so that I can see how big the teardrop shapes are and whether the 225/45 turn without any pause inbetween gets you aligned with the runway centerline. (Any suggestions on how to make sure I'm later able to correlate the GPS track with the test results that I wrote down? Other than making sure my watch is synced with the GPS time, and write down the time of each individual test?)

Any tips on record keeping? Anyone has a handy form or something for this kind of stuff?

Other safety items:
I'll be doing this in the R2160 which is cleared for aerobatics, will be flown within the "A" limits, and I am very current in aeros/spin recovery etc. in this aircraft. I have in the past pulled the mixture to ICO in-flight and I know the engine will windmill above Vs and catch immediately as soon as mixture is restored. Everything will be done at altitude, over an area with plenty emergency landing opportunities. Airspace will be the Rotterdam TMA (class E) with permission/traffic service from ATC.

Any additions?

[24Carrot]

I think the GPS is a good idea, as you never quite know what you will want to analyse later.

Noting the QNH, ground temperature (and ideally the OAT at some relevant height) allows for some CAS/TAS conversions later.

Which is important because at altitude your TAS should be higher and your turn rate (at any given bank angle) should be slower, though the angle of descent should be the same.

Which, if I have this right, means that real turn backs are harder on low density days, with the height loss inversely proportional to density.

[BackPacker]

I don't have very high hopes for that GPS. Best it does is one track point per second. And of course the vertical accuracy can be as little as +/- 50 feet. But since I've got that GPS anyway, why not?

A fellow pilot has some professional equipment that's used to accurately track racecars, and he's trying to adapt that for aerobatics tracking. Maybe once that's ready we'll give it another go.

[24Carrot]

The GPS might be more useful than you think. During my PPL training I usually had a Garmin H eTrex in the back. It was much more useful for Nav than analysing circuits though. (I did an awful lot of circuits:ugh:).

The absolute height accuracy can be well off, eg I tracked my first helicopter solo, and found I picked up and set down at -200ft agl, and no I wasn't in the Netherlands! However the error can be quite stable, which means descent rates can be quite accurate. Headings and turn rates require some assumption about the wind, but can also work out well.

Assuming the unit had enough satellites to start with, the big problem was when it lost or acquired one. That was when you got the sudden jumps. I was pretty sure of the reason because in a circuit the same jumps always occurred when I turned through the same headings.

If you analyse it in a spreadsheet, you can work out the energy change per time step, omit the "impossible" jumps, and look at the trends on either side. So with some effort, even "hiker GPS" data can be useful.

------
Incidentally, in case any PPL students reading this might think GPS tracks are a good way to analyse circuits, my experience suggests not. I never learned anything useful from them. By contrast, GPS tracks were incredibly useful during Nav, not least for showing the FI you had actually gone where you said you did!

[Genghis the Engineer]

I got an excellent plot off my GPS from my recent real turnback with a partial loss of power. It helped a lot in my personal debrief.

Backpacker - I do a lot of assessment of flight test plans and flight test reports, but within a structured test environment. I would recommend if you are going to do this safely that you make sure you understand briefing and debriefing for flight test, get somebody else to listen to and critique your brief, understand the use of test cards, and probably fly with an experienced pilot as a safety observer. Also make sure that all of the aspects of flying you'll be demonstrating you are fully current in, before putting them together. The standard technique for assessing difficulty of flying a manoeuvre (usually referred to as "pilot compensation") is the "Cooper Harper Rating Scale" - there's a lot about it on the web, but you may find it useful to run your CH task construction past a test pilot who has done the formal training in its use.

G

[peterh337]

GPS altitude is normally accurate to within 10-20ft - so long as you get good reception.

However some older products, notably those using the popular SIRF-2 chip, had a systematic altitude error of about 160ft. I can't remember which way it went. Basically they did not correct for the deviation from the ellipsoid, IIRC, which in the UK is a certain fairly constant figure.

[Mark1234]

Just a couple of thoughts.

IF you can safely set up a small video (eg a gopro) that can film the panel / altimeter, start it, film the GPS time, then let it run. That way you can sync the two up. Just a variation on the theme of photographing the GPS time so you can geotag photos after the fact. There are also some GPS's (e.g my cycle one) that have baro altitude.)

The other thought is that you don't seem to have a way of considering positioning. I'm not sure it is feasible, but for example e.g. if method 1) makes the turn in 300ft, but leaves you 1/2 a mile further away than method 2), which takes 400ft, which is favoured?

Otherwise, I look forward to the results. In retrospect, I think the my approach probably isn't/wasn't representative, as it pre-supposes you're making the turn.

[Genghis the Engineer]

GPS altitude is normally accurate to within 10-20ft - so long as you get good reception.

However some older products, notably those using the popular SIRF-2 chip, had a systematic altitude error of about 160ft. I can't remember which way it went. Basically they did not correct for the deviation from the ellipsoid, IIRC, which in the UK is a certain fairly constant figure.


Pretty irrelevant - between start and end of the manoeuvre, the total altitude change will be below 1000ft in probably any light aeroplane. In analysing something like this, it's just differences, not absolute values - and the GPS is in that case, giving a more exact reading than anything a pressure altimeter will give you anyhow since it's unaffected by PEC.

OAT and pressure altitude will give density altitude near enough, and those can just be recorded at stable conditions before manouevring.

Even if flying take-off to landing for a manoeuvre like this, the same applies for data analysis because GPS will flatline on the runway (and given that PEC varies with airspeed and may be affected by ground effect, a pressure altimeter may not, although it'll be close enough to allow analysis if you had airspeed as well).

G

[chrisN]

If you do a 360 turn at constant speed and bank, you can calculate wind speed and direction at that height from the GPS points.

Chris N.

[BackPacker]

Chris, good one. I'll do that at the start.

Mark, unfortunately I do not have a decent camera, and the half-decent (actually, more like quarter-decent) camera I have will be hard to mount properly. Nevertheless, I'm going to see if I can make it work with that one.

[mm_flynn]

Even if flying take-off to landing for a manoeuvre like this, the same applies for data analysis because GPS will flatline on the runway (and given that PEC varies with airspeed and may be affected by ground effect, a pressure altimeter may not, although it'll be close enough to allow analysis if you had airspeed as well).

G
I had a different experience. I was using a garmin gps60 from memory to log takeoff performance with a sample rate IIRC of either 1 sec or 1/2 sec. There appeared to be some interaction between the aircraft acceleration and the altitude. I started motionless at pretty much Airfield Elevation. As I accelerated, I dipped about 20 feet below the surface and then seemed to come up to the surface at about rotation, and then showed a normal climb out. It made it quite difficult to assess where the actual wheels off the ground event occurred. The deepest 'under ground' was at slightly over half my estimated ground run and there wasn't a really clear trajectory change anywhere. (As one would expect in a series of max gross takeoffs the initial climb was quite slow)

[foxmoth]

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

Been a bit busy the last couple of days so missed this reply to my post - but what a STUPID comment. NOBODY, least of all me said that a turn back is the ONLY way to deal with a EFATO - landing ahead should always be the prefered option if the area allows and AFAIK this whole discussion was about if it could be done IF NEEDED this is of course going to mean it will only be for a limited number of locations and NOT finding the one exception that will counter any argument.

[BackPacker]

Okay, trip report. This was, as planned in the Robin R2160. Actual weight was approx. 730kg, vs. an MTOW of 900kg. QNH 1027, OAT zero C @ 3000' which was my "close throttle" height for most tests. OAT on the ground 4 C, dewpoint 3.

From the POH: Vs 63 kt, Vbg 78 kt, Vy 78 kt.

(i) From height, establish the aircraft in a Vbg stable, trimmed descent. Mark attitude with some sticky tape on the canopy. Write down/time V/S.
(ii) From height, establish the aircraft in a Vbg stable, trimmed descent at 45 degree bank left and right. Mark attitude again with some sticky tape. Write down/time V/S.
(iii) From height, establish the aircraft in a Vbg stable, trimmed descent with the mixture closed. Write down/time V/S.

V/S at Vbg, zero AoB, with throttle closed was 800-900 ft/min.
V/S at Vbg, 45 AoB with throttle closed was 1100-1200 ft/min. Stall warner was going off, but no noticeable pre-stall buffet was felt.
V/S at Vbg, zero AoB, with mixture closed was 1000-1100 ft/min.

The sticky tape on the canopy was really useful. It allowed me to set the proper attitude in the subsequent tests immediately.

The difference between throttle closed and mixture closed is between 10 and 20%. So we need to correct all subsequent measurements for that.

All V/S were from the VSI. I did not want to spend a lot of time descending through 2000 feet or more and timing the descent with a stopwatch. Maybe next time.

All items start from a stable, properly trimmed Vy climb along a line feature, into the wind as far as possible. When passing through a certain safe height (3000' most likely, weather permitting) I'm going to pull the power and:
a. Hold the nose up to see how long it takes for the aircraft to stall. Then recover the stall and see how much time/altitude I lose before in a stable Vbg glide.
b. Hold the stick in the same position, furthermore as in (a).
c. Completely release the stick, let the aircraft sort itself out, furthermore as in (a).
d. Fly the aircraft in a half-G pushover, furthermore as in (a).
e. Fly the aircraft in a ballistic arc (zero G), furthermore as in (a).

A couple of surprises here.
- The fuselage angle between Vy (full throttle) and Vbg (closed throttle) is actually only about 40 degrees or so (20 degrees nose up vs. down). Because of this, it really doesn't matter whether you do a zero or half G pushover, or simply let the nose drop all by its own. In all cases (except a and c) I was fully established in a Vbg glide while I dropped through the "close throttle" altitude.
- Holding the nose up as in (a), it took 4 seconds for the stall warner to sound, and 7 seconds for the aircraft to be properly stalled. But even then, I was able to recover to a stable Vbg glide 100' below the "close throttle" altitude.
- Completely releasing the stick (as in (c)) got the aircraft in a huge pitch/speed oscillation. I let the aircraft descend over 1000' but by then it had not yet recovered from the oscillation so I ended that test prematurely.
- Despite Vy being equal to Vbg for this aircraft, there was a *huge* difference in trim. With the R2160 the all-flying tailplane is in the propellor slipstream and that will be the primary reason. I expect this to be different in different aircraft.

Subsequent tests include one second of "oh ****" time after closing the throttle, then:

f. Establish Vbg according to the best technique from (a)-(e), then turn into the crosswind 225 degrees at 45 degree bank, turn the other way 45 degrees at 45 degree bank.
g. Same as (e) but with 60 degree bank
h. Same as (e) but with 30 degree bank
i. Like (f) but start with a left turn 45 degrees away from the crosswind, then turn 225 degrees into the crosswind (teardrop thus reversed). Altitude lost should be the same as (f), but you never know.

I actually used two seconds of "oh ****" recovery time after closing the throttle.

With (f) I was able to consistently complete the maneuver in 450'. At the end I was in a stable Vbg descent, and all I would need to do is flare. That flare obviously takes a few feet. The (limited, see further down) GPS data I have suggested that the 225/45 degrees works quite well to regain the centerline in the no-wind situation. I was too high up to confirm this overhead a line feature though.

(g) and (h) gave me 800' and 700', respectively. I only did this once but the data suggests another confirmation of Rogers.

(i) was also done in 450'.

Both (f) and (i) felt really comfortable. Especially during the 225 degrees turn, there is time to do something else, like issuing a very quick mayday call to make sure the runway is cleared.

j. Like (f) but this time roll into a 45 degree bank while pushing the nose down (at half or zero G as appropriate), ready to pull as soon as the Vbg attitude has been set.

This did not make a significant difference. Dropping the nose from Vy climb to Vbg is a very quick process, and so is rolling to 45 bank. I did this test only once and lost 450', just like (f) and (i).

k. Like (f) but use the Mark1234 technique of immediately rolling to 60 degrees bank, pull to the stall warner while the nose drops, play angle of bank against stall once the nose is at the Vbg attitude.

I tried this a number of times. It feels like a very aggressive maneuver which requires very precise aircraft control. I would not be happy doing this for real - it feels like it's too easy to lose control. But it did give better performance: The full maneuver was completed in 400' both times I tried.

I will also run an outdoor-type GPS which has track recording

The track recording of the GPS turned out to have an interval of approx. 5 seconds. It doesn't really help me with the analysis. I also had a camera installed in the cabin (which was indeed not even half-decent) but unfortunately it was not aligned properly and the instruments are not visible.

To summarize, I was able to complete the turnback consistently in 450', with only moderate technique. Obviously this was a very limited test and that number should be corrected for a number of things:
- I was not able to confirm that I would be able to make the runway. Just that the turnback would be completed in that altitude. Properly reaching the runway might require a further glide and thus further altitude. And obviously all this depends on climb performance anyway: If your climb performance (angle) is less than your best glide performance (angle) you'll never reach the runway even if you were able to turn back without altitude loss.
- I flew all maneuvers with the throttle closed. As my initial tests showed, we need to correct the numbers with approximately 10-20% to compensate for the residual idle thrust.
- All figures still need to be corrected for OAT, altitude, QNH and the fact that I was well under MTOW.
- All figures are specific for the R2160
- All figures are specific for *my* pilot technique. YMMV.

Personal lessons learned:
- You have about 2-3 seconds to recover from the "Oh ****" reaction. It doesn't matter all that much how fast you react and how aggressive you pushover as long as you don't stall. Whatever energy you lose on the way up, is recovered on the way down. (Obviously the longer you dally, the further you end up from the runway.)
- You have to fly the aircraft to the Vbg stable attitude. Just letting the plane sort itself out doesn't work, especially considering the huge trim change.
- Knowing the proper Vbg attitude is very important. The faster you can set this, the earlier you can start the turn and concentrate on other matters. And the Vbg attitude was less nose down than I thought.
- The turnback (225/45 or 45/225 as appropriate, at 45 AoB), with the engine windmilling, will take *at least* 500 feet, and possibly closer to 600-700 feet under the wrong circumstances. You then might need some additional altitude to reach the threshold. For me personally, this means I'm going to keep on using 1000' as minimum turnback altitude, assuming a straight-out departure. (Turning crosswind at 500' obviously greatly improves your chances to make the runway though.)

Note: All the usual caveats apply. Do not change the technique you've been taught just because some anonymous bloke dumped a few numbers plus some mumbo-jumbo in an anonymous internet forum. If you decide to deviate from the technique that's been taught to you by a qualified instructor, you do so at your own risk, and I suggest you first validate your prospective technique yourself. Yada yada.

[Big Pistons Forever]

April 12, 2012

A light aircraft that crashed into two houses in Peel Green in Salford, killing the pilot, probably suffered a fuel supply problem, an air accident report revealed.

No-one on the ground was hurt but the Piper PA38's pilot, Ian Daglish, 59, died later in hospital, the report from the Air Accidents Investigation Branch (AAIB) said.

Mr Daglish's 19-year-old passenger Joel McNicholls was seriously hurt in the crash on the morning of July 29 last year.

Leaving Manchester/Barton City Airport, the aircraft suffered an engine stoppage on take-off at about 200ft. It rolled to the left, with the extension roof of the first house most likely being struck by the aircraft's right wing.

The underside of the aircraft then hit the side wall of a neighbouring house, with the wrecked and on-fire aircraft coming to rest in a driveway between the two homes.

The AAIB report said: "The account of the passenger and the findings from the investigation support a fuel supply problem as being the most likely cause of the engine stoppage."

The AAIB went on: "Although other potential causes for the engine stoppage could not be eliminated from the investigation, the most likely cause, based on the available evidence, was that stiffness of the fuel selector valve and wear on the rod connecting it to the selector handle, may have resulted in the valve being in an intermediate position during the take-off.

"This would have reduced the fuel flow to a level too low to sustain continuous engine operation."

The report added: "The suddenness of the engine stopping and the limited time available to react to it probably resulted in the pilot omitting to lower the nose before the aircraft stalled.

"Once the aircraft stalled, it is highly unlikely that he could have recovered the aircraft in the height available." Father-of-two Mr Daglish, from Alderley Edge, Cheshire, was a military historian and wrote a series of books about Second World War battles.

He described himself on his website as a "battlefield mythbuster". Colin Maher, whose home was hit, said at the time that he had run into his garden and saw the plane alight. "I heard a man shout for help and just put a hosepipe on him," Mr Maher told the BBC.


The above was quoted from another post.

Sadly another fatal EFATO crash that started with a departure stall. Theorizing about turnbacks is all fine and dandy but too often the point is moot because the aircraft was allowed to stall when the aircraft lost power. If you are looking for something new to practice on your next local flight establish the aircraft in a Vy climb, in trim, and retard the throttle to idle. The object is to go right to the glide attitude. In other word after the aircraft has stabilized its speed should be right on best glide without you having to make any further adjustments to the attitude. It is harder than it sounds and a good way to build the automatic reactions that will save your life.

[Genghis the Engineer]

Theorizing about turnbacks is all fine and dandy but too often the point is moot because the aircraft was allowed to stall when the aircraft lost power

As the lead theorizer about turnbacks, nonetheless I agree with you totally.

If, for any reason, an aeroplane is permitted to stall anywhere between about 20ft and 400ft, almost certainly all bets are off, the height loss will probably take the aeroplane into the ground out of control.

This is irrespective of what you are going to try and do next. There just isn't time and height for a pilot who wasn't expecting a stall to recover.

G

[Shaggy Sheep Driver]

What worries me about the PA38 accident above is that pilot (who I knew, incidentaly) did not lower the nose when the engine failed yet transmitted a mayday and may have (according to the report) also switched off the mags and fuel.

Having suffered a partial engine failure in a Chipmunk at almost the exact same spot as Ian's accident (off 09R at Barton), I know the importance of INSTANT forward stick cannot be over emphasised. All the other stuff (radios, mags, fuel) can wait (especially the radio).

[Genghis the Engineer]

It's very hard to put yourself in the head of somebody who has had an accident and sadly is unable to talk about it.

However, I know that at a few points in my flying career where I've returned to training I've been picked up for following "procedure" (checklists, radio...) in preference to the primacy of controlling the aeroplane. As an instructor I've seen this in other pilots as well.

That *may* perhaps be what happened.

G

[Shaggy Sheep Driver]

Agreed we'll never know for sure.

But I think there's a lesson here for pilots and instructors regardless. ALWAYS FLY THE AEROPLANE! If you haven't got the stick and rudder stuff right, nothing else matters. Only when the aeroplane is stable and under control should anything else be even considered. Checklists have their place, but YOU MUST FLY THE AEROPLANE as the number one consideration, regardless of any checklist or procedure. And last of all comes the radio.

The old addage 'aviate, navigate, communicate in that order' was never more true.

[Flamin_Squirrel]

Couple of questions from a low hours PPL:

A stall during an EFATO when properly trimmed has to be induced by the pilot pulling back, allowing speed to bleed off. From my limited experience flying C172/PA-28, the amount of pulling back to cause such a stall has to be fairly significant and not easily missed. Is it easier to miss this sign than I realise, or does panic simply cause pilots to miss this important warning sign?

As for turning back, what are peoples views on doing so from a crosswind position? Is it worth making a turn onto crosswind even if for you'd otherwise be departing straight out as it keeps you closer to the airfield and if the airfield has crossing runways then a 180 turn could have you lined up nicely on final for an xwind landing?

[Piper.Classique]

But I think there's a lesson here for pilots and instructors regardless. ALWAYS FLY THE AEROPLANE! If you haven't got the stick and rudder stuff right, nothing else matters. Only when the aeroplane is stable and under control should anything else be even considered. Checklists have their place, but YOU MUST FLY THE AEROPLANE as the number one consideration, regardless of any checklist or procedure. And last of all comes the radio.

The old addage 'aviate, navigate, communicate in that order' was never more true.
*



Says it all, really.


A stall during an EFATO when properly trimmed has to be induced by the pilot pulling back, allowing speed to bleed off. From my limited experience flying C172/PA-28, the amount of pulling back to cause such a stall has to be fairly significant and not easily missed. Is it easier to miss this sign than I realise, or does panic simply cause pilots to miss this important warning sign?

well, it depends on the exact type and configuration. Also, if you see the ground rushing up at you the _tendency_ is to pull back to avoid it. Sometimes called groundrush (or panic, if you prefer)

[Cows getting bigger]

Control the crash. If you don't control the crash, you will probably die.

[riverrock83]

As a student (note my lack of experience in what I'm saying below), I've always been taught to push forward on the stick to get the plane into the glide attitude.

You have to remember that when the engine failure happens, you are probably going to be in the climb attitude and trimmed as such. I would be surprised if there are many aircraft which have the same trim settings for climb and glide!

When you practice basic stalls, you normally start from straight and level flight, then reduce the throttle and try to maintain the straight and level attitude. The speed will of course slowly wash off, in such a way you can feel the different stall characteristics of your particular plane. It might be useful to try stalling from the climb attitude (I would talk to an instructor before trying this!) - the stall is likely to be quite different- speed loss will be much quicker. Gravity isn't your friend...

[Gertrude the Wombat]

It might be useful to try stalling from the climb attitude
Yes. And the other one you should be taught is stalling in a descending turn (mostly with the intention of getting you to avoid it), to try to reduce the number of people who kill themselves turning final with a tailwind.

[Shaggy Sheep Driver]

A stall during an EFATO when properly trimmed has to be induced by the pilot pulling back, allowing speed to bleed off. From my limited experience flying C172/PA-28, the amount of pulling back to cause such a stall has to be fairly significant and not easily missed. Is it easier to miss this sign than I realise, or does panic simply cause pilots to miss this important warning sign?

If the aeroplane is climbing after take off at full power, it will be trimmed for that - no pulling back required.

When the engine fails the aeroplane, unless the pilot does something about it, will remain pitched nose high (not quite as high as before as removal of power will induce pitch reduction in itself), the speed will rapidly bleed off due the nose-up pitch and no power, and within a few seconds (3 in this case of a benign PA38) the stalling angle will be exceeded and the aeroplane will depart controlled flight. All this with no pulling back.

In very light aeroplanes flown to max climb performance the stall will occur pretty much as soon as the engine fails. At Barton about 30 years ago a highly experienced GA instructor, examiner, and B737 training captain (the guy who had meticulously checked me out on the Chipmunk) was climbing at max rate in an Issacs Fury. The engine failed and the Fury stalled and spun immediately. He was seriously injured.

When the engine fails in a climb it is essential to LOWER THE NOSE IMMEDIATELY, and perhaps quite violently, to prevent loss of control.

[Monocock]

I, as always, find people's carefully planned actions with EFATO's genuinely interesting. There are those who have had one, and those that might, one day.

There is a lot of theory printed above; theory that in the circumstances just won't have the chance to be activated. EFATO's often happen (real ones) at 300 feet or less. There isn't the time to start calculating. By the time you have realised what's happened you have lost 33% of your height already.

A stationary propeller will give an exceptionally poor glide ratio and you can't imagine how poor it is. The silence will scare you. The sound of the yoke rubbing on the panel and the control cables squeaking on their pulleys behind you will make you feel lonely.

You will drop like a brick. Literally. Not like the "idle engined" situation that you practice in your exams or your biennial.

My point is, if you plan too hard, you might end up doing yourself out of time when you need it most. Time that requires you to think about what the air is doing over your airframe, and what you can do to reduce your chances of potentially injurious rapid deceleration on the ground.

Sorry to sound blunt, but when it happens it is completely different to how the theorists describe it to be.

[Shaggy Sheep Driver]

When it happened to me it was a shock that it'd happened but I sure didn't have a think before lowering the nose. I lowered the nose while my brain was getting into EFATO gear. Pavlov's dog syndrome - 'X' happens, you do 'Y'. No thinking involved - there ain't time!

[Monocock]

I completely agree SSD

My comments were aimed more at the theorists who were quoting reams of scientific forumlae. :bored:

[thing]

Just a thought from a glider and power jock. In a glider you always trim for glide speed (I know it can't be done that precisely but about half forward on the trim is usually about right) before take off, thus assisiting your aim of not stalling in case of a cable break. This means of course having highish forces on the stick on climb out during a winch launch but they are quite acceptable.

What would be the problem in doing that in a powered a/c, say up to a thousand feet then trim for the climb? Wouldn't it be worth doing? Has anyone tried trimming for glide speed, leaving the trimmer alone then trying a take off?

One thing that gliders prep you for is a launch/take off failure, cable breaks happen far more often than an engine failure. I've just looked in my logbook and I had six launch failures out of the last one hundred, that includes two winch failures/poor winch technique. Unconsciously I'm always expecting a 'launch fail' even in a power a/c.

[Pilot DAR]

was climbing at max rate in an Issacs Fury. The engine failed and the Fury stalled and spun immediately

Yeah, there is a less than universally understood concept, which most of us have been guilty of ignoring, to our own peril;

The steeper the climb, the slower the airspeed. The slower the speed, the higher the drag. The higher the drag, the faster the plane will slow down when you take the power away. There comes a point where the pilot just will not get the nose down fast enough, and a stall is assured.

A pilot should expect that the plane can be easily glided from at engine failure at Vy. An engine failure at Vx may be somewhat different, and extra skill will have to be applied. Slower than Vx (which is certainly possible) is much worse. It might not be possible following, a sudden engine failure, to lower the nose fast enough to accelerate to glide speed. In that case, you're going to stall before you can establish a glide. Game over.

There are phases of flight which we get into, which we will not be able to get out of following an engine failure. All helicopters have them - it's called a height/velecity curve. Airplanes have them too, but they are not documented. This is probably because airplanes are not expected to be operating in those regions of flight. Aside from slow flight training, there just is no reason. In slow flight training, you should have lots of altitude to recover the stall which will result.

I have done this testing in a modified Cessna Grand Caravan, and it was very scary! My experience with microlights is limited. I do know that they have less inertia, and so are even more vulnerable to this than certified light planes.

Vx to assure that the obsticle is cleared. Vy or faster after that. Yes, altitude is your friend, but not if you foresake airspeed to get it!

[foxmoth]

My point is, if you plan too hard, you might end up doing yourself out of time when you need it most. Time that requires you to think about what the air is doing over your airframe, and what you can do to reduce your chances of potentially injurious rapid deceleration on the ground.


Sorry, that is rubbish - ALWAYS, the first thing is to lower the nose. THEN If you have beforehand thought about where you are going that DOES reduce the chances of "potentially injurious rapid deceleration on the ground." because you are then not spending all your time thinking "where do I go now", pre planning should be giving you more time when you need it - if it does not, then you have done your planning wrong - but it does need to be simple and achievable.

[ivorPhillips]

Here is a great Video and narrative on the AOPA website, youcan get access

For free, Mooney impossible turn,

http://flash.aopa.org/asf/pilotstories/impossibleturn/ (http://flash.aopa.org/asf/pilotstories/impossibleturn/)

[Big Pistons Forever]

The May issue of Pilot has a write up on the Manchester Pa 38 crash. The aircraft nose was never lowered after the engine failed and the aircraft stalled and spun in......But the mags and fuel were off and a Mayday call was made :(

This is an accident which raises disturbing questions about how the pilot was trained. It is hard to not draw the conclusion that during training a lot more emphasis was placed on doing the engine failure drills than flying the aircraft........

Finally the AAIB tests should be a wake up call. At a Vx climb unless the nose is lowered; from engine failure to the start of stall/spin/die sequence is only 3 seconds.

As I have said in earlier posts if you want to practice an exercise that will give you the automatic reactions that will save your life in the event of an EFATO, at a safe altitude establish a Vx climb and smoothly but quickly close the throttle. You should be able to immediately lower the nose exactly to the gliding attitude every time. If you have never done it the first time will be an eye opener. This is one exercise where the first time you try it should not be when it suddenly gets very quiet right after takeoff....

[piperboy84]

Turn Backs: On a lighter note, in my particular case on the farm strip landing straight ahead is not only an option it is in fact the desired choice by far, regardless if I have plenty attitude for a turn back. The reason being the farmer owning the fields past my strip heading appears to have been more diligent and massively more skilled when ploughing his fields for grass sowing, so much so that the results of my attempts at purposely ploughing/cultivating and levelling my field for the sole intention of taking off and landing falls far short of his results for livestock grazing. (The smarmy git has got it like a friggin grass version of Heathrow)