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Required Altitude for Engine Out Return to Airport

Hey All,

Testing our experimentals is what this category is all about. Good on those who put the rigor into the process.

A discovery I made in my RV-7 CS MT Prop is that there is a remarkable difference between idling at full coarse pitch in a glide and pulling all the fuel out of the engine at full coarse.



The power lent from idling our engines should not be discounted whether you have a fixed or variable prop.


I agree that power at idle is not a totally accurate simulation of engine out.

So I wonder, with a C/S prop, how much better the simulation is if you do NOT pull the prop back but leave it forward at high rpm to generate drag. The idea being to overcome the thrust of the idling prop with the drag.

I wonder how much more accurate the simulation becomes.
 
Right place for prop control at idle to sim 'No Power'

If I were to leave the prop at high RPM at Idle I would have an excessive rate of descent. If memory serves me correctly around 1,550 ft/min because the engine is robbing too much energy. With the prop at full coarse at idle I get around 950 ft/min which is too low because the engine is adding energy at that setting. Setting the prop speed to 1400 RPM at idle gives me 1,100 ft/min. 1,100 ft/min is the best glide I can achieve when I am in full coarse, mixture in fuel shutoff, and throttle partially open to achieve at least 12" MAP (again, no fuel/no power, just allowing the engine to breath and thus less energy stolen from glide).

Everybody's package is going to demonstrate different performance numbers, mine may be no good for the next airplane. But I feel strongly that we each at least consider that our performance at idle will be very different than true power out.
 
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Idle Thrust

....But I feel strongly that we each at least consider that our performance at idle will be very different than true power out.

This is TRUTH!

Idle thrust is part of the reason that many folks obtain seemingly very unrealistic altitude loss numbers during simulated turn-backs, particularly in fixed-pitch aircraft.

The other fallacy that leads to unrealistic turn back altitude numbers is that folks practice a 180 degree turn which is unrealistic for a single-runway turn back. 270-90 is a more realistic scenario.

I am totally convinced that many folks believe that they can accomplish a full-engine out turn back from absurdly unrealistic low altitudes and this is part of the reason that we occasionally see bad accidents in this scenario, even from experienced pilots.

Skylor
 
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Turn Back

We don't know and will never know how many successful turn backs have occurred
Airplanes like the Bonanza 36 series and at least some Mooney's are not good candidates for turn back and too often make the headlines. Many biplanes are in the same category, although most are not as bad as the 36. My very limited testing with the 36 told me that I would not consider a turnback below 1500' AGL.
The only way to know for sure the performance of an individual airplane is to climb to a safe altitude over a long and quiet runway, shut down the engine, stop the prop and measure performance.
For one example the Pitts S2B will glide significantly further with the prop stopped vs windmillling or idle.
My personal criteria would be engine restarted at or above 3000' AGL.
 
The option to turn back to the runway should only be considered viable when it is part of the departure brief. Single pilot operations included. If it isn't briefed, then don't do it. The required altitude and direction of turn need to be set prior to takeoff.
 
Stopping the prop is not realistic. In most cases that I have experienced the prop continues to rotate unless there has been a major engine failure or the airspeed has been significantly reduced.
 
The option to turn back to the runway should only be considered viable when it is part of the departure brief. Single pilot operations included. If it isn't briefed, then don't do it. The required altitude and direction of turn need to be set prior to takeoff.

In absolute agreement here.
 
Stopping the prop

Stopping the prop is not realistic. In most cases that I have experienced the prop continues to rotate unless there has been a major engine failure or the airspeed has been significantly reduced.
In the Cassutt it is easy. Just pull up vertical for a roll and it will stop very quickly if you don't keep a touch of positive G to keep the fuel flowing. In a Cherokee 180 I had to hold the airplane near stall but got it stopped.
 
In the Cassutt it is easy. Just pull up vertical for a roll and it will stop very quickly if you don't keep a touch of positive G to keep the fuel flowing. In a Cherokee 180 I had to hold the airplane near stall but got it stopped.


And both of those procedures slow the plane down. I wouldn't suggest doing that when you only have a few seconds to get the plane back on the ground safely.
 
Restart

In the Cherokee I had quite a few seconds before landing and always got an easy restart. In the Cassutt it took about 180 statute before the prop would turn and then quick restarts.
I did a lot of acro in the Glasair I and kept a touch of positive G so the engine never quit.
The Cassutt was unintentional the Cherokee intentional. Quiet 5000' runway underneath me if I didn't get a restart.
 
Resources

I posted these in a similar thread; but for folks not familiar here is some peer reviewed work regarding the physics of the turn-back:

The Feasibility of Turnback from a Low Altitude During the Takeoff Climb Phase:
https://www.nar-associates.com/technical-flying/jett/jett_wide_screen.pdf

Here are some additional articles on the topic:

Estimating the Turnback Altitude from the POH:
https://www.nar-associates.com/technical-flying/impossible/EstimatingTurnbackAltitude.pdf

The Penalties from Using Non-optimal Turnback Parameters:
https://www.nar-associates.com/technical-flying/impossible/nonoptimalcost_screen.pdf

The Possible "Impossible" Turn:
https://www.nar-associates.com/technical-flying/impossible/impossible_wide_screen.pdf

Should you Turnback?
https://www.nar-associates.com/technical-flying/impossible/possible.html
 
Turn Rate/Radius Management

This is an academic discussion. I'm not advocating for any specific maneuver in the event of power loss during takeoff phase other than to maintain a safe angle of attack all thee way to the landing site, wherever that may be.

When we look at aircraft turn performance, we are concerned with turn rate (degrees per second) and turn radius (feet). Only two factors effect turn performance: true airspeed and radial G. Maximum instantaneous turn performance occurs at the aerodynamic limit of the airplane and maximum sustained turn rate occurs ONSPEED (a zero Ps condition). In the technical resources in the previous post, Dr. Rogers develops the thesis to support the use of a 45 degree bank at Vs + 5 for optimum turn performance in the conduct of a turn back. Similar performance with a better aerodynamic margin can be achieved at an ONSPEED AOA condition for a very small penalty in turn performance.

One way to picture that is to use a rate/radius diagram which is a "snapshot in time" of aircraft turn performance. Here is sea-level turn performance for my RV-4 equipped with a 160 HP engine:

3c039a_e46cb14f6a54414d87e6045fc2b0b8de~mv2.png


In a horizontal turn, it is not possible to maintain energy if you exceed maximum sustained turn (the region above the solid red line in the chart), the airplane "bleeds" energy and the harder you pull, the slower you go. An ONSPEED AOA cue allows the pilot to precisely fly the solid red line. At lower speeds, note that the difference between maximum instantaneous turn performance and maximum sustained turn performance is negligible.

The turn back maneuver is performed in an orthogonal plane, i.e., you have vertical turning room available, and with the engine out, your thrust is being generated by gravity, so the chart isn't 100% applicable; but the point is that optimum turn, glide and approach and landing AOA are all coincident with ONSPEED alpha. This provides more aerodynamic margin than slowing to Vs + 5 for the turn for a very small penalty in turn performance. Here are some tests at altitude using an ONSPEED turn and a "buffet turn" (i.e., right at the aerodynamic limit of the airplane): https://youtu.be/ZQrOskngSlQ

Here are a couple of data plots of an actual low-altitude turn back test to a full-stop landing. The first plot shows pressure altitude and actual angle of attack (measured relative to the fuselage reference line in the RV-4):

3c039a_e0a415055847469dbe8b23c0174b09a6~mv2.png


The second plot substitutes KIAS for AOA:

3c039a_b58f8d8c5f304ce891e6bc8abeb9c8de~mv2.png


The important thing to note is that the AOA is consistent throughout the maneuver. It is necessary to "unload" the airplane when turning (i.e., adjust pitch to maintain AOA). This maneuver is more difficult to accomplish without an accurate AOA/energy cue.

The closer to the end of the runway you are, the more turning you have to do. In Dr. Roger's papers, the airplane is a sufficient distance from the runway to allow a "teardrop" pattern to be flown. If you are closer to the runway, more turn will be required--much closer to 250-260 degrees with an additional 60-70 degrees required to align with the runway. You can see this in the video: https://youtu.be/jI_o41SkKOw. The wind was 4-5 knots, 080-090 during these tests, so there was no appreciable cross-wind to turn into to reduce turn radius. Turns are made in both directions.

My RV-4 is equipped with a fixed pitch propeller and the test depicted in the charts is performed at IDLE, residual thrust is not measured. A nominal 45-50 bank is used for turn back and re-alignment. Flaps 20 is selected after a 3" delay after power is reduced to idle and before commencing maneuvering. This flap setting improves turn performance and provides more lift than drag; but will reduce straight line gliding distance. An ONSPEED condition provides maximum ENDURANCE glide, flaps up. As flaps are deployed ONSPEED and L/Dmax airspeeds begin to marry up.
 
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math error

I posted these in a similar thread; but for folks not familiar here is some peer reviewed work regarding the physics of the turn-back:

The Feasibility of Turnback from a Low Altitude During the Takeoff Climb Phase:
https://www.nar-associates.com/technical-flying/jett/jett_wide_screen.pdf

Here are some additional articles on the topic:

Estimating the Turnback Altitude from the POH:
https://www.nar-associates.com/technical-flying/impossible/EstimatingTurnbackAltitude.pdf

The Penalties from Using Non-optimal Turnback Parameters:
https://www.nar-associates.com/technical-flying/impossible/nonoptimalcost_screen.pdf

The Possible "Impossible" Turn:
https://www.nar-associates.com/technical-flying/impossible/impossible_wide_screen.pdf

Should you Turnback?
https://www.nar-associates.com/technical-flying/impossible/possible.html

in 10 min of reading, found a math error in first paper. equation 11 to 12 lost a "2". not sure if it is a printing error or even if it makes a difference. I question validity of results.

"Why do bridges fall down? we give you partial credit."

For me the bottom line: 1) if i decide to turn back, be prepared to land short; like "where I make your turn" short.
2) There is no shame in making a crosswind departure to stay close to airport on climb out.
 
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in 10 min of reading, found a math error in first paper. equation 11 to 12 lost a "2". not sure if it is a printing error or even if it makes a difference. I question validity of results.

"Why do bridges fall down? we give you partial credit."

For me the bottom line: 1) if i decide to turn back, be prepared to land short; like "where I make your turn" short.
2) There is no shame in making a crosswind departure to stay close to airport on climb out.

The missing "2" reappears in the sentence which follows equation (14). So it looks like a printing error or typo, but doesn't affect the calculation of the bank angle for minimum altitude loss (45°, but note that lower bank angles probably reduce the risk of stall-spin, and thus increase the odds of living a long life. Optimum bank angle for longer life after engine failure on take-off is likely 0°).
 
Optimum bank angle for longer life after engine failure on take-off is likely 0°).

This is an answer I really, really like.

Too many variables in aircraft, airports, and pilot skill to make any general suggestions of minimums that are valid for the majority of cases.
 
Folks should operate their aircraft within their comfort zone and ability level. I can easily make a turnback from 500' AGL in my RV-4 and have practiced it numerous times. What hasn't been mentioned very much is one doesn't necessarily have to make the runway at most airports. If you can get inside the fence you will normally be much better off than landing in a neighborhood or a grove of trees.
 
I went and try the impossible turn on the Microsoft Flight Simulator 2020 using the Cessna C172 Skyhawk that has the o360 engine.

I tried the turn back at three altitudes: 500ft, 700ft, and 1000ft.

All three altitudes did not result in returning back on the runway

The 500ft and 1000ft resulted in landings way short of the airport perimeter. The 1000ft was the worst.
The 700ft landed close to the airport perimeter but you have to fly an optimum climb angle.

The engine shutdown was accomplished by pull the mixture control all the way aft instead of pulling the throttle to idle.

From experience, I thought the flightsim model is a bit more draggy than on the real airplane. However, it was a good exercise of getting a real dose of reality seeing the sim aircraft never made it back to the take off runway.

I also tried to fly the slicker Diamond DA40NG. This aircraft higher glide ratio allowed it to return to inside the airport perimeter, but it crash way short of the runway. I haven't flown this aircraft that much in the sim but if I have more hours, then the result will probably be better but probably not survivable. In any case, the ability for all the aircraft to return to the take off runway was zero.


Test condition for C172:
28 gal of fuel
170lb pilot + 170lb passenger
wind calm
Runway length: 5000ft
 
I went and try the impossible turn on the Microsoft Flight Simulator 2020 using the Cessna C172 Skyhawk that has the o360 engine.

I tried the turn back at three altitudes: 500ft, 700ft, and 1000ft.

All three altitudes did not result in returning back on the runway

The 500ft and 1000ft resulted in landings way short of the airport perimeter. The 1000ft was the worst.
The 700ft landed close to the airport perimeter but you have to fly an optimum climb angle.

The engine shutdown was accomplished by pull the mixture control all the way aft instead of pulling the throttle to idle.

From experience, I thought the flightsim model is a bit more draggy than on the real airplane. However, it was a good exercise of getting a real dose of reality seeing the sim aircraft never made it back to the take off runway.

I also tried to fly the slicker Diamond DA40NG. This aircraft higher glide ratio allowed it to return to inside the airport perimeter, but it crash way short of the runway. I haven't flown this aircraft that much in the sim but if I have more hours, then the result will probably be better but probably not survivable. In any case, the ability for all the aircraft to return to the take off runway was zero.


Test condition for C172:
28 gal of fuel
170lb pilot + 170lb passenger
wind calm
Runway length: 5000ft
I've flown 100s of engine outs in the Pitts and the P-51 in DCS World with a VR headset, mainly just to get my brain used to the sight picture, and to (hopefully) reduce the "oh, darn" delay time before I get the stick forward. The Pitts almost always makes it back to the airport, and usually the runway. I have absolutely no idea if the models are accurate, and how they might relate to my RV-8, but I think it's the only place I will practice a turnback after takeoff. I will fly more turnbacks at altitude in the RV-8 using some of these techniques, but I continue brief to land straight ahead, whether it's on remaining runway, in a field, on a road, forest, lake, etc.
 
...

The important thing to note is that the AOA is consistent throughout the maneuver. It is necessary to "unload" the airplane when turning (i.e., adjust pitch to maintain AOA). This maneuver is more difficult to accomplish without an accurate AOA/energy cue.

The closer to the end of the runway you are, the more turning you have to do. In Dr. Roger's papers, the airplane is a sufficient distance from the runway to allow a "teardrop" pattern to be flown. If you are closer to the runway, more turn will be required--much closer to 250-260 degrees with an additional 60-70 degrees required to align with the runway. You can see this in the video: https://youtu.be/jI_o41SkKOw. The wind was 4-5 knots, 080-090 during these tests, so there was no appreciable cross-wind to turn into to reduce turn radius. Turns are made in both directions.

My RV-4 is equipped with a fixed pitch propeller and the test depicted in the charts is performed at IDLE, residual thrust is not measured. A nominal 45-50 bank is used for turn back and re-alignment. Flaps 20 is selected after a 3" delay after power is reduced to idle and before commencing maneuvering. This flap setting improves turn performance and provides more lift than drag; but will reduce straight line gliding distance. An ONSPEED condition provides maximum ENDURANCE glide, flaps up. As flaps are deployed ONSPEED and L/Dmax airspeeds begin to marry up.
Mike, this is very impressive. What do you feel would be the altitude penalty for a stopped prop, assuming the engine failed catastrophically, or a windmilling prop with zero power?

Using an easy to understand energy management tool like ONSPEED and good flight instruction, I could see a day where we all train and practice turnbacks like glider pilots do, and like you demonstrate in the video.
 
I've flown 100s of engine outs in the Pitts and the P-51 in DCS World with a VR headset, mainly just to get my brain used to the sight picture, a.

The sight picture was the thing that caught me by surprise when I first tried it. The low altitude and the steep 45 deg bank in a GA airplane are not something we do everyday.
 
I went and try the impossible turn on the Microsoft Flight Simulator 2020 using the Cessna C172 Skyhawk that has the o360 engine.

I tried the turn back at three altitudes: 500ft, 700ft, and 1000ft.

All three altitudes did not result in returning back on the runway

Did you check out @Vac’s videos on YouTube? It’s silly to dispute real life demonstrations (down to as low as 250’) with video game simulations.

I agree with others that pilot skill and comfort level are chief factors, and in an emergency they should stick to what they know they can accomplish.
But both skill and comfort level can be augmented through training and practice.

I, for one, really appreciate @Vac’s thorough presentation and am now convinced flying AOA will help me achieve more consistent maneuvers. Perhaps one day I’ll even be confident with a low altitude turn back to runway.
 
Not Just Altitude

In one of the recent seminars, an owner of a Cherokee with a tired engine learned that the higher he went, the further from the airport he would crash. His climb gradient was less than his glide angle, so continuing to get higher also took him ‘furtherer’ from the runway. His airplane would not make back to the runway, no matter what he did.
 
In one of the recent seminars, an owner of a Cherokee with a tired engine learned that the higher he went, the further from the airport he would crash. His climb gradient was less than his glide angle, so continuing to get higher also took him ‘furtherer’ from the runway. His airplane would not make back to the runway, no matter what he did.
In aircraft like this, one possibility is to do a "circling climb" over the airport, or at least to climb in the vicinity of the airport.
 
In aircraft like this, one possibility is to do a "circling climb" over the airport, or at least to climb in the vicinity of the airport.

As you say - possibly. The excess lift needed for climbing might be lost in the constant bank angle. In that case perhaps flying squares would be a little better.
 
Academic discussion only:

Mickey, to answer your question, I don't know. I've conducted power-off testing at altitude and have developed a rule of thumb that I dovetail into the low altitude tests to compensate for residual thrust effect; but they are only applicable to my airplane and are based on a crude assessment (no drogue or torque measurements). Also, ambient conditions have a large effect on performance (especially wind). Skylor Piper is always correct to point out these residual thrust effects may provide a false sense of "can do." And, has also been pointed out, the type of prop fitted has a significant effect on power-off performance; so you are correct to point out that the nature of the failure may impact glide performance. The lowest drag occurs with the propeller stopped (that's why multi engined airplanes have feathering propellers); but stopping a prop at low altitude with a non-feathering propeller is problematic. I believe that a CAFE test of various types resulted in a recommendation to not consider stopping the prop below 3K' AGL (i.e., more harm than benefit at low altitude). We put a discussion about this in the RV Training Manual (sticky at the top of the safety page). If you know what you are doing and have sufficient experience stopping a light-weight fixed pitch propeller is fairly straight-forward. You can certainly do it at a lower altitude than, say a metal two-bladed constant speed type, however that would induce a high work-load if you are flying the airplane and simultaneously running a checklist.

Kevin is correct to point out optimum performance occurs at zero degrees of bank. Once you roll, it becomes a more complicated turn rate/radius/energy management endeavor. One thing to consider is that RV's typically have a climb angle that is steeper than glide angle. This performance means that a turn back may occur relatively close to the end of the runway. In the video tests in my previous post, here's a data plot of the 7th (full stop landing) iteration:

3c039a_7c8ab086d8ac471b9d336aad4b5ed9be~mv2.png


The red line is bank angle. Positive numbers are right bank, and negative numbers are left bank. Because I have the benefit of listening to my AOA, the turn back is an "eyes out" visual maneuver. I'm only approximating 45 deg of bank by using the horizon. My primary visual scan is to the inside of the turn (where the airplane is going)--I'm occasionally glancing forward to check bank angle (where the airplane is pointing). You can see that I'm actually underestimating it a bit.

A previous post pointed out that a relatively steep bank like this close to the ground is uncomfortable if you aren't used to operating in the low altitude environment. There is considerable "ground rush" below 300' AGL, and it takes some training and experience to be able to ignore this and concentrate on what we used to call "velocity vector management" during low altitude training in the Air Force. The velocity vector is the same thing as flight path--it's where the airplane is going, not necessarily where it's pointing. To learn how to land, we all get pretty good at assessing the part of the runway that isn't moving up or down in the windscreen when we're on final. That's where the flight path of the airplane is going. It takes more practice to see that on the inside of a turn, but if you have good (RV) visibility and don't need to cross-check inside the cockpit (aural cuing), you can learn to pick out a similar spot on the ground to make a long/short assessment. Also, once bank angle goes back to zero (or becomes less steep), the flight path will shift further away from the airplane--i.e., you "fall" in the turn (higher VVI), but once the lift vector (where your lift is going) is vertical (bank angle zero), the aim point/flight path move further away from your nose (lower VVI). That's why the physics are such that you want to get the turn out of way as quickly as possible.

One thing to note in the plot is the second turn required to align with the runway. In the video I use the jargon "reposition" to describe the angle of this turn. I'm below 100' above the ground as I start this turn, and if you look at the green line in the plot, you'll see a slight increase in AOA. This second turn is fairly steeply banked and requires a healthy "unload" (easing the stick forward in the turn) to maintain a steady AOA. I have the benefit of an accurate AOA cue and am flying AOA as my primary reference, not airspeed. You can see without that type of cuing, a combination of ground rush and the necessity to change direction by 45-70 degrees could easily result in a stall at that point. If my RV-4 had any excess inside rudder (skid) and I stalled at that point trying to stretch the glide or because the ground rush caused an instinctive reaction to pull back on the stick, it would snap roll into the ground: https://youtu.be/cLg_LGjpL9Q

If you are further away from the end of the runway, the turn back becomes more of a teardrop shape and the alignment turn isn't as much of a threat. This turn geometry is discussed in the academic papers I previously posted links to.

Fly safe,

Vac
 
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Did you check out @Vac’s videos on YouTube? It’s silly to dispute real life demonstrations (down to as low as 250’) with video game simulations.

I agree with others that pilot skill and comfort level are chief factors, and in an emergency they should stick to what they know they can accomplish.
But both skill and comfort level can be augmented through training and practice.

I, for one, really appreciate @Vac’s thorough presentation and am now convinced flying AOA will help me achieve more consistent maneuvers. Perhaps one day I’ll even be confident with a low altitude turn back to runway.

First of all, I don't have a personal airplane that I can try out the impossible turn. Secondly, I don't have the skill to test out in a real airplane, maybe except at a high altitude. The best course of action is to test out using the flight simulator. I have used this simulator for an extensive amount of time so I was able to gauge the difference between the sim airplane and the real airplane, in which there are some differences. One of the more noticeable differences is the sim airplane is more draggy than the real airplane especially on final.

From my perspective, the sim flying was to train for engine out procedure and to view the sight picture when the engine quits and to practice the 45deg turn. This event occurs very low to the ground, and most people will be startle by this fact alone. Keeping the airplane in a 45 deg bank at extreme low altitude is not normal, and I know I would be fighting the urge not to level the airplane. So what does it all mean? This means if I am not comfortable flying the impossible turn in a simulator, I will never be comfortable in a real airplane. Everyone has to make this judgement for oneself.
 
In one of the recent seminars, an owner of a Cherokee with a tired engine learned that the higher he went, the further from the airport he would crash. His climb gradient was less than his glide angle, so continuing to get higher also took him ‘furtherer’ from the runway. His airplane would not make back to the runway, no matter what he did.

This was my observation from the simulator too.
 
Phat,

That gentleman is Rick Marshall. He's conducting a meta analysis of turn back data to see what's in the art of the doable for developing training techniques to assist with making a pre-takeoff assessment and conducting this type of maneuver, including the feasibility of developing an assessment tool (app).

Rick's salient observation is that if glide angle is steeper than climb angle, return is problematic. This is discussed in Dr. Rogers paper: https://www.nar-associates.com/technical-flying/impossible/EstimatingTurnbackAltitude.pdf. You can see this graphically depicted in my previous post. The slope of the climb portion of the pressure altitude plot is steeper than the glide portion, allowing for the conduct of the turn back maneuver. RV's have a low power loading (weight/hp), which translates to good climb performance. For a Cherokee, it is more critical to follow manufacturer's recommendations for maximum performance during takeoff and initial climb to generate the best possible climb:glide angle ratio. In some cases, performance in some airplanes may not allow this. Rick's analysis method cleverly uses ADS-B data and corrects for wind, allowing him to look at all takeoffs. There is considerable variation in pilot technique, resulting in significant variation in climb angle.

The tests in my previous post where conducted as part of that project. Anyone is welcome to contribute test results to the project via email. Instructions are in Charlie Precourt's column in Sport Aviation. If anyone needs contact information, drop me a PM.

v/r,

Vac
 
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I've been working on this impossibility all summer with loads of practice time. I've concluded that it was named 'impossible turn' because it is impossible to give a pilot a specific number (safe turn around altitude) for a particular aircraft type that will work in all scenarios/all conditions.

Specific to an RV-4, here's my result - not maximum effort: https://youtu.be/zGY3uTsZ6mk
 
I've been working on this impossibility all summer with loads of practice time. I've concluded that it was named 'impossible turn' because it is impossible to give a pilot a specific number (safe turn around altitude) for a particular aircraft type that will work in all scenarios/all conditions.

Specific to an RV-4, here's my result - not maximum effort: https://youtu.be/zGY3uTsZ6mk

This demonstrates that you can safely handle a failure which causes the engine to suddenly go to idle, if you know the event will occur on that take-off. If the engine fails, the glide performance will be quite a bit worse. If you aren't expecting the event on that take-off, your performance will likely be worse.

Have you compared glide performance with mixture at ICO vs glide performance with engine idling?
 
When practicing you always know when the engine fails but the numbers are wrong. An engine out is drastically worse than an idling engine and there is no way to simulate it. Also and engine out on take off never ever happens at a convenient time and then there is the lag time for you realize what just happened. That also cannot be simulated because each time you go flying you maybe in a different frame of mind and reaction time varies.
 
I try to practice an engine failure on take-off as the first take-off of the day. I can make it from 500' AGL even with a 5 second startle factor. You can't practice a stall or spin either because you know it is coming . . . but I still do. I also practice engine out from everywhere in the pattern. I'm actually crosswind at 500' AGL most of the time. I have started letting the crosswind carry me away from runway centerline to make a turnback more doable.
 
I always thought the question is wrong in the first place.

It's not a question of altitude it is a question of energy. How much energy do you need to turn around? It makes a big difference if you fly at Vy or Vx or you speed up to 130mph because the RV cools nicely and climbs well at that speed and you fly from a 9000foot runway before you start climbing.

If you are hanging there at Vx which for me is actually close or below power off stall (my polar is a bit noisy that far down) you would have to first do a stall recovery before you can even turn at which point you will have lost quite a bit of altitude and hopefully can land straight ahead (feels like recovering from a glider winch rope break...). So I obviously never actually climb that slow.. . I go at least above power off stall speed even in a small field.

On the other hand at 130mph I can turn as long as I am high enough for the wing not to touch .... .

So what does it mean then if somebody says I turned at 250 feet? It's pretty meaningless.... .

Oliver
 
One thing I rarely see discussed in "impossible turn" debates or articles is what I would consider to be the most important decision factor -- where is the airport and what is around it?

Take off from Denver International and lose an engine and you have at least 10 miles of flat farm land in each direction. Or, if heading East, 500 miles of farms, including Nebraska. No problem. Ditch.

If you take off from Santa Monica airport heading East and lose an engine, where exactly are you planning to land? (Or LAX heading East, or O'Hare heading East.) Most urban areas aren't exactly brimming with 1000 foot long, 50 foot wide strips of land that are vacant of telephone and light poles. As I recall, Harrison Ford lost an engine out of KSMO and landed at a golf course, but that might not be something everyone is going to spot in an emergency. And a lot of cities don't have golf courses adjacent to airports.

As an early poster in this thread put it, "the airport has rescue vehicles and few obstructions. If I have to crash, I'd like to crash there". You give me a choice of a crash landing on a taxiway or runway median after an impossible turn with a rescue truck on the way versus straight ahead into an office or apartment building, and I will take my chances with the turn every time.
 
An engine out is drastically worse than an idling engine and there is no way to simulate it.

I guess I disagree with these statements. It is slightly worse. And you can simulate it by just pulling the mixture to cutoff. (I recommend over a suitable landing site just in case).
 
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