Impossible Turn Practice

steamee

steamee

Pre-takeoff checklist
Joined
Jun 1, 2009
Messages
102
Display Name
Display name:
Steamee
I've been reading and seeing a lot about the impossible turn coming from AOPA the last week or so. I wouldn't say they were promoting it but in my training this was never even brought up as a possibility to practice. What do people here think about this?

I have to say I'm with the guy in the video. I don't see myself being able to be that cool about it in the event of an actual engine fail.
 
I also intend to practice this. If the "impossible turn " is Possible is practiced, it can become one of the tools available in an emergency. It is definitely something that needs practice. Dave
 
I did some experimentation with my airplane once (open cockpit, low power, high drag) and the result convinced me I didn't need to practice...'cause right then and there, I resolved never to do it for real. I lost a surprising amount of altitude. The plane came around so sluggishly that I felt that there was a good chance of an accidental stall in the heat of the moment. That didn't even factor in the runway alignment issue....

Mind you, I included a two-second YGBSM delay at the beginning before starting the turn itself. I suppose practice would help, but I think I'll keep the procedure off my options list.

Ron Wanttaja
 
I tried the practice one day.

If I pushed over to best glide immediately on failure, it was barely doable.
But when I added the YGBSM delay of a couple of seconds before pushing, it wasn't possible to turn. I expect that there was a significant loss of energy during those two seconds in high AOA/high drag before pitching for best glide. Wouldn't do it for real... I'll just land straight ahead or make gentle turns left or right, and concentrate on hitting whatever I hit with minimal energy.
 
Here's the thing - what altitude are you starting at? There are alot of factors involved. The impossible turn may or may not be impossible depending on how high you are when the engine quits. Some airplanes will glide better than others. Making the 180 when the engine quits in a PA28 at 500' may be perfectly doable. In something more complex like a PA32 - 500' probably isn't going to be enough.

If you are going to consider the turn back to the runway, know how much altitude you need and know your airplane.
 
Here is a video of the impossible turn in an aussie bi-plane. It was a real engine failure on climb out with fatal consequnces. IIRC the mooney in that video that did the impossible turn last year still had some engine power.

WARNING!!!! WARNING!!!! THIS IS A DIFFICULT VIDEO TO WATCH!!!!
IF YOU ARE SQUEAMISH DON'T WATCH IT!!! I have posted the link only to show what would often happen in the impossible turn.

http://www.youtube.com/watch?v=DFWMBT1zDlI
 
AdamZ said:
Here is a video of the impossible turn in an aussie bi-plane. It was a real engine failure on climb out with fatal consequnces. IIRC the mooney in that video that did the impossible turn last year still had some engine power.

WARNING!!!! WARNING!!!! THIS IS A DIFFICULT VIDEO TO WATCH!!!!
IF YOU ARE SQUEAMISH DON'T WATCH IT!!! I have posted the link only to show what would often happen in the impossible turn.

http://www.youtube.com/watch?v=DFWMBT1zDlI
Click to expand...

That video is pretty rough. Is it just me, or does it look like his turn was uncoordinated from the start (way too much rudder)?
 
It all depends on the aircraft you are flying. There's a Kitfox knockoff that I fly, that I've personally made the determination that I will try the turn if I'm >450' AGL with a relative level of comfort. In some other aircraft, no way.

Ryan
 
Capt. Geoffrey Thorpe said:
I didn't watch the video, but one needs to overcome the hours and hours of training and practice that conditions us to pull as we roll into a turn...
Click to expand...

I don't think it is a matter of overcoming the pull - it is about the discipline to unload the wing when you need to. You can and still need to pull a little in the turn, but you when you feel the wing start to stall or the horn chirp, you better be disciplined to ease it off and not keep pulling.
 
Practice, learn to know your limitations as well as those of your airplane. My 'number' looks like 700' and I include that as part of my T.O. brief. I think you really have to know the best glide pitch angle without reference to instruments.
 
I've done it (practiced) in a Warrior III at about 650 feet, and made it back with no issues. This thread has sparked my interest though, next winds calm day I go up, I'll try the teardrop at 500'. The Warrior is a pretty good glider, but we'll see what happens.
 
Arbiter419 said:
I've done it (practiced) in a Warrior III at about 650 feet, and made it back with no issues. This thread has sparked my interest though, next winds calm day I go up, I'll try the teardrop at 500'. The Warrior is a pretty good glider, but we'll see what happens.
Click to expand...

i'd recommend you try it at altitude a few times to figure out how low you would be comfortable thinking about it down low.
 
So many factors could influence whether you could make it back from a particular height in a particular airplane, and some of them could be a lot different in a real failure then when you practiced. I'd recommend taking the altitude you "made it" at and at least doubling it in your preflight briefing.

And I'm still gonna teach my students that if their single engine fails before reaching at least 1000 AGL their primary duty is to maintain control, then pick any place in front or off to the side (but not behind) and concentrate on flying the airplane at minimum energy all the way into a wings-level return to earth.
 
A few comments:


  1. this is completely altitude-driven. Altitude = energy = how far you can glide.
  2. "practicing" with power idle <> engine out :)no: !!!!!!!!!!) Do NOT count on one or two practice attempts at altitude ("Yeah, I made a 180 and lost 500' at idle, so I'll be able to make it back no problem once I'm 500" AGL...")
  3. The push from climb to glide is significant. Unless you've practiced this and know how it feels you'll never make it.
  4. you don't have to land on the runway at most airports.
  5. Some airports (KTEB ) don't have many good "straight ahead" options.
  6. The bank angle required that close to the ground is outside most pilots comfort range.

I turned back in the Chief after throwing a plug over Fairmont, WV and losing most of my already anemic power. I would not have made it back without that residual power. If the engine died I was dumping it in the river if I couldn't make the field I had just picked out.
 
Last edited:
The turn is technically possible, though that depends on runway length, terrain/obstacles around the runway, wind, the altitude at which you begin at, whether you have a full or partial power failure, etc.

Whether you want to consider this for inclusion in your bag of tricks or not is a personal decision. I think both "yes" and "no" are reasonable answers. I don't consider "never ever ever, always straight ahead" a reasonable answer, because despite how we practice these things, your engine never promised you that it would only fail totally. The only loss of power I've ever experienced was partial, due to carb icing on departure, and it occurred to me that I never practiced "partial loss of power" and really had never even given it much thought. It would be pretty silly to have "land straight ahead" hard-wired into your brain when you have a plane that is still capable of generating enough power to maintain altitude or greatly extend the glide.

But I think one thing is clear, practicing this maneuver should be done at a simulated higher altitude and not down low at "real altitudes". I know there's at least one fatal in the NTSB database where somebody was practicing this down low.

The other thing I think is clear is that you have to know what the maneuver actually is and not just make one up, which a lot of people seem to do. Googling for the paper "The Possible Impossible Turn" should be a good reference. That should also give you a good idea of what factors influence the practicality of this maneuver, and for what altitudes it might be possible.

If you haven't done your comm, you might also consider looking up the comm maneuver "power off steep spirals" in the Airplane Flying Handbook.

Realistically, you're never going to have to perform this maneuver, but I think that going out and practicing any maneuver is a good thing as long as you do it in a sane and safe manner, and practicing this maneuver down low at 500AGL would not fit that description.
-harry
 
Never practiced it, don't think I will. I was always taught, look for a soft spot in front of you. While the reward is high for completing the turn (no / little aircraft damage), the risk is also very high for the maneuver. If you stall, the likely hood of surviving is low.

If you pick a spot in front of you, land gear down, minimal speed, ...... Yes, you may be injured, but if you find a field, soft spot, injury should be minimal.
 
Last edited:
Arbiter419 said:
This one...I may be 100% wrong, but with a stopped prop, wouldn't the airplane be a slightly more efficient glider?
Click to expand...

At idle power (600-1000 RPM) there is some thrust (release the brakes on pavement and see if you roll forward). Better yet, hand prop something.

Even my measly 65 (ha!) HP Lycoming pulls at 800 RPM.
 
dmccormack said:
At idle power (600-1000 RPM) there is some thrust (release the brakes on pavement and see if you roll forward). Better yet, hand prop something.

Even my measly 65 (ha!) HP Lycoming pulls at 800 RPM.
Click to expand...

would it still pull you forward if you were pointed into a 50 or 60 mph wind?
 
Doesn't it seem like there was a lot of open area where they could have landed? Of course you can't see all angles, but...

attachment.php
 

Attachments

  • Impossible turn.gif
    Impossible turn.gif
    69.7 KB · Views: 148
My instructor has me practice the impossible turn almost every time I do a BFR. We do it at 500'. I generally climb at greater than best glide, so I always have to remember to pull to best glide and make a coordinated turn at 45* bank. Most of the time the problem I have in the 172 is over-shooting the runway because I'm still too high to land, which means for me the maneuver would be N/A with strong headwinds. With low to moderate headwinds, > 500', and no good option in front of me, I'd do it.
 
Arbiter419 said:
This one...I may be 100% wrong, but with a stopped prop, wouldn't the airplane be a slightly more efficient glider?
Click to expand...

Unless you have something mechanically jam the engine the prop will continue to turn.

The difference between idle and prop windmilling on your Warrior will be pretty insignificant. Airplanes with larger props or constant speed props will have a bigger difference. Some will mention that you can pull the constant speed prop back to increase the glide, but at 500 feet on the upwind you are going to have to be pretty well on top of your game to remember to do so.

Also don't forget you will be landing downwind at a likely much faster ground speed than you are used to. Also be aware of the ILLUSION OF SPEED as you get closer to the ground. It will look like you are going much faster than you are. For these reasons I find practicing at altitude is useful but may be pretty optimistic as to what you might expect in an actual event.

I practice these regularly from 200' in gliders, but my descent rate is about 200fpm. 500ft is about the absolute minimum I would even consider it in a power plane, and I would have to be pretty familiar with what that plane was capable of.

Brian
CFIIG/ASEL
 
Last edited:
Early in my training, before ever hearing about the "Impossible Turn", my instructor guided me through one of these. We made it, and I thought it was a logical maneuver. Then my 3rd instructor told me about the Impossible Turn, and scared the crap out of me.

When I saw this AOPA article, I thought it was irresponsible of them to even propose the idea. But, being a logical person, I re-read it and gave it some thought. I plan to go through the exercise at altitude to see how I feel about it.
 
Fearless Tower said:
Here's the thing - what altitude are you starting at? There are alot of factors involved. The impossible turn may or may not be impossible depending on how high you are when the engine quits. Some airplanes will glide better than others. Making the 180 when the engine quits in a PA28 at 500' may be perfectly doable. In something more complex like a PA32 - 500' probably isn't going to be enough.

If you are going to consider the turn back to the runway, know how much altitude you need and know your airplane.
Click to expand...

You're right that there are a lot of factors. In addition to knowing how much altitude your plane loses in the turn, you can pay attention to whether you have reached that height (AGL) by the time you cross the departure threshold, because if you haven't, you may not be able to reach the runway after a turnback (although this will depend on your climb and descent angles).

The above does NOT guarantee that you will have enough altitude to make it.

Here is some of what I have been taught:

-At sea level with no wind, at max gross a 172 or 182 requires about 3500 feet of runway. (I assume this is on a standard day.) Each knot of headwind decreases the runway length needed by about 130 feet.

-If your climb angle is less than your descent angle, then extra altitude above the required turnaround height hurts instead of helping, because of how far you had to travel away from the airport to gain that altitude. Consequently, it's beneficial to climb at Vx instead of Vy.

-Calculate the necessary climb rate prior to take off, and then watch to see if you get that climb rate. The formula I was given is that the climb rate, in hundreds of feet per minute, needs to be at least the ground speed in knots divided by the glide ratio. For a Cessna 172 or 182, the glide ratio was stated to be about nine-to-one, and can be adjusted by adding one for each seven knots of headwind.

-If you see that you are not getting the needed climb rate, consider turning crosswind early and climbing in the pattern.

-Land straight ahead if possible.

-Practice turnbacks regularly at altitude or don't even try it.

Note that I am not saying that any pilot should or should not try this. This is only a summary of what I have been taught.
 
AdamZ said:
Here is a video of the impossible turn in an aussie bi-plane. It was a real engine failure on climb out with fatal consequnces. IIRC the mooney in that video that did the impossible turn last year still had some engine power.
Click to expand...

That's far too similar to the Franklin's recent accident. What's up with engine failures with wing-walkers up top and virtually instant post-crash fires? :(
 
CAuker, I can tell you that if you made it in a Warrior II from 600 you had some residual thrust.

900 is more like it, and that with a bit of a departure headwind (5 knots) on a 3000 foot strip.
 
bbchien said:
CAuker, I can tell you that if you made it in a Warrior II from 600 you had some residual thrust.

900 is more like it, and that with a bit of a departure headwind (5 knots) on a 3000 foot strip.
Click to expand...

I always wondered, why practice the impossible :hairraise::D
 
bob_albertson said:
I always wondered, why practice the impossible :hairraise::D
Click to expand...
Well....think about how many PVT ASELs have currency doing power off 45 degree banked turns at Vy+5 (just above stall) and then rolling out after 225 degrees to Vglide?

Now add to that pilots in Arrows with the gear extension system who can nail that and not stall it.

Now add to that.....well you get it.
 
bbchien said:
Well....think about how many PVT ASELs have currency doing power off 45 degree banked turns at Vy+5 (just above stall) and then rolling out after 225 degrees to Vglide?

Now add to that pilots in Arrows with the gear extension system who can nail that and not stall it.

Now add to that.....well you get it.
Click to expand...

Oh yeah, definitely a handful for even someone who does practice the turn.

I was of the opinion that if you had enough altitude to practice the impossible turn that you should always aim for the half-way point of the runway. That way when you loose the small amount of thrust that idle power gives you won't end up short of the runway. The problem, as you also pointed out in the past, is that the pucker factor and/or flight or flight response kicks in and we tend to get tunnel vision. Tunnel vision to the extent that we focus only on the runway and forget rule number 1... always fly the plane. It definitely is sad when I hear about an accident where the plane lands just short of the runway at a high descent angle.

Sometimes the most survivable option is to land ahead somewhere since you can manage the energy a little better and have a better shot at making the softest and slowest impact as possible. The impossible turn sure seems like a hard thing to force yourself NOT to do.... After all there is a long paved and obstruction free area right behind you whereas you might be looking a rolling terrain with a lot of vegetation ahead of you.

I haven't read the entire thread, so forgive me if I've stepped on any toes

Bob
 
AdamZ said:
Here is a video of the impossible turn in an aussie bi-plane. It was a real engine failure on climb out with fatal consequnces. IIRC the mooney in that video that did the impossible turn last year still had some engine power.

WARNING!!!! WARNING!!!! THIS IS A DIFFICULT VIDEO TO WATCH!!!!
IF YOU ARE SQUEAMISH DON'T WATCH IT!!! I have posted the link only to show what would often happen in the impossible turn.

http://www.youtube.com/watch?v=DFWMBT1zDlI
Click to expand...

That's a stall/spin.
 
Watched the video, it is difficult, but I agree, with all that flat terrain, why not just put it down straight ahead? I wish we had terrain like that to work with at the home drome...on 24, between the housing developments, roads, terrain and wooded areas, not any really good places to put down. 6 is better since there's a cleared area just off the departure end past a busy road...on 15 and 33 there are no good alternatives.

When I was working on my PVT, we always did teardrops back to the departure end of 6 and 24 but not until we were at or close to TPA in the 172. We also did a few steep turn power out landings in the pattern just to show me the capability of the plane to handle these situations. Maybe a commercial ticket will be next on the list to fully explore these maneuvers.

Of all the things that give me the willys, or better yet, "give me pause" it's losing the engine just off the field beyond the runway. That's why I pat the spinner everytime we get back home.

My current CFII drums into me that if the plane just doesn't feel right immediately on the roll, shut it down and walk away...too many people try and will the plane into the sky even if it's not behaving properly.
 
I use, if I'm not at Rotation speed in 14 seconds, I'm thinking about shutting it down. It's approximate but works very well for my average loads.
 
You must log in or register to reply here.
Back
Top