Impossible Turn...POSSIBLE?!

[FloridaMan]

I’ll also mention that the FAA/FSDO was calling me repeatedly within minutes of landing in that field. Everyone here should carry AOPA extended legal protection as, while there was no warning of imminent failure and all of my documentation was current and correct, it was nice to have them to advise me. 

[Stetson20]

On 5/31/2019 at 4:43 PM, mike_elliott said:

Bob,

180 will point you in the right direction, but you are left or right of the runway, you need 2 more 45 deg turns to line up. Total = 270. Practice this at altitude, Bob. What you are after is the altitude loss number. Once you have that, you know your absolute minimum turn back to the airport. No need to adjust, 45 Deg is the most efficient bank. 

Once you have that altitude, I use it as a "kill zone" checklist item. Ill raise flaps, check ldg light off, verify gear up, lower nose to cruise climb from Vy, adjust the turbo models MP accordingly.

 

I saw exactly this in the video. The pilot was forced to do 2 more steep turns near the ground to align with the runway. I'm not sure how much altitude it would have taken to be successful, but a *left* turn to the crossing runway seemed the logical choice to me as I watched the video. I think the left turn would have kept him over cleared land throughout the turn. 

Just an armchair QB observation. Regardless, kudos to the pilot for putting it down safely.

[Yetti]

Each of the scenarios for turning back requires some really fancy flying really close to the ground.  To pull off a 75 degree bank turn when most folks have not practiced a 45 degree bank turn recently is pretty much out of the question.   There needs to be a fair amount of pilot tricks in the pilot bag to have a successful outcome.   The other thing is the engine has to cooperate with engine out scenario that you have practiced.   Sure you practiced for 800 feet.  What do you do at 700 feet.  Also as I was taking off yesterday, I was over the far fence at 800 feet, then realized the field is 300 feet. and I was taking off from the low end of the field.  So was 800 feet AGL?  What is the difference between 16 and 34 Threshold elevation.  crap now I have to do math while the engine is sputtering and my pulse is racing.   

[Hank]

1 hour ago, Yetti said:

Also as I was taking off yesterday, I was over the far fence at 800 feet, then realized the field is 300 feet. and I was taking off from the low end of the field.  So was 800 feet AGL?  What is the difference between 16 and 34 Threshold elevation.  crap now I have to do math while the engine is sputtering and my pulse is racing.   

Do the math on the ground, at 0 KIAS, indoors in the cool air. Write it down. If you have trouble, look at it.

Your math should be based on field elevation, to match the numbers on your altimeter. 

When the sh!t hits the fan, you won't have time or brain power for mental math, or even counting on your fingers. 

[Austintatious]

2 hours ago, Yetti said:

Each of the scenarios for turning back requires some really fancy flying really close to the ground.  To pull off a 75 degree bank turn when most folks have not practiced a 45 degree bank turn recently is pretty much out of the question.   There needs to be a fair amount of pilot tricks in the pilot bag to have a successful outcome.   The other thing is the engine has to cooperate with engine out scenario that you have practiced.   Sure you practiced for 800 feet.  What do you do at 700 feet.  Also as I was taking off yesterday, I was over the far fence at 800 feet, then realized the field is 300 feet. and I was taking off from the low end of the field.  So was 800 feet AGL?  What is the difference between 16 and 34 Threshold elevation.  crap now I have to do math while the engine is sputtering and my pulse is racing.   

Sorry ti whoever suggested it, but a 75 degree bank turn is a REALLY REALLY bad idea.  Not only are you going to sacrifice a lot of altitude, you are going to build up a good decent rate that you will have to arrest.

We do this maneuver in  gliders for emergency training for rope breaks.  200 feet is doable for us (however we typically use 300-400 feet when actually practicing).  45 degree bank is OPTIMUM and typically you are pulling full spoilers after the turn to get down.  And yes, the glider comes down just as fast as a powered ship (faster even) with full spoilers.

The Advice I posted earlier in the thread was given precisely because it allows you to make the in air judgement without math.  You still have to do your planning on the ground before takeoff.  I brief the pre planned critical points to myself before every Self launch or Tow in a glider. I do the same for SE (especially because I have experienced an engine failure/crash after takeoff in a SE).

 

in Short,  Know how much altitude you need to do the return (see the method already posted)

If the engine fails before that altitude, pick a point in front of you

If it fails after the altitude, make the 45 degree bank turn and POINT THE NOSE DOWN AT THE RUNWAY NUMBERS Or better, a point that will let you line up with it 1/8th mile prior.

now there exist 3 scenarios:

1- Watch airspeed, if it is increasing GET OUT DRAG!  Your ground speed will be high with a tailwind you are in danger of an overrun.  You need to kill the energy. 

2- If airspeed is not increasing with the nose pointed AT the runway numbers, target best glide speed and ELIMINATE drag (flaps up, speed brakes, feather prop, no slip) Now you can observe and see if you will make the runway or not, if not then pick a good place to go down.

3-  If with the nose pointed AT the runway numbers, the airspeed is decreasing, DONT STALL!  You will not make it, accept this and pick a good place to go down.

 

You definitely have to do some math on the ground, but The above are easy judgements to make in air that do not require math.  Pointing the nose DOWN at the runway numbers basically assures you will not stall and lets you quickly evaluate what needs to happen.

 

I still believe that a 45 degree turn shortly after takeoff for about 10-15 seconds then a turn to paralleled the runway center line is a very safe maneuver/precaution.  It puts you into a position where a 180 turn lines you up to the center line of the reciprocal runway.  The direction you want to turn/offset depends on the terrain and winds at the time and place of departure.  Turn downwind initially if a crosswind exist.  Turn TOWARDS whichever side has the better land out options in case the engine fails while below the turn back altitude while on the 45 degree leg.

 

Edited June 3, 2019 by Austintatious

[Pete M]

20 hours ago, pmccand said:

I can’t believe that I missed posting this thread earlier, but I have personally performed the “Impossible Turn” as a result of total engine failure on my FIRST UNSUPERVISED SOLO!  I was at 500 feet AGL just after take off in a Cessna 150.  It was just the day before, my instructor showed me a procedure that “might save my life some day”.  Turned out to be the VERY NEXT DAY!  

BANG! No engine just after rotation and climbing through 500 feet after take off.  Declared an emergency, pushed the nose over, simultaneously dropped 10 degrees of flaps continued turn at best glide speed.

After getting the Mooney, I tried to duplicate the turn at altitude.  Take it from someone experienced at this...There is NO way in hell that the Mooney could have successfully made that maneuver at 500 feet.  NO WAY at all.  The turn can be made, but you need a LOT more altitude with the Mooney, so now when I am close to the ground, I look for something soft, flat and inexpensive straight ahead.  I still do practice the maneuver, but my decision height to turn around is now much higher than with a Cessna.

A short body will make the turn...you just have to do it correctly. See above. Heavier, Higher wing loaded airplanes...dont know...

[Pete M]

On 6/2/2019 at 9:58 AM, Shadrach said:

Maximum turn to sink ratio is what you want. That’s what aligns the plane with the runway with the most altitude. This is basically a descending chandelle (I brain farted the term Immelman in an earlier post , but I’m reading a book about WWI tactics so forgive me). If you look at Dave Keller’s track, he flew a question mark shaped pattern back to the field and and barely stopped before runway’s end. I too have practiced the maneuver many times. My best results occurred with a very steep initial turn that progesssivle shallowed at the 90 degree mark. In my experience this results in the most rapid course reversal with the least altitude lost and the least amount of maneuvering to realign with the runway.  

Progressively shallowed AFTER the 90dg point? Sounds about right.

[Pete M]

23 hours ago, FloridaMan said:

I have not done power off 180s in the Rocket yet. It’s something I need to practice along with going up to altitude and testing elevator authority at different trim settings and speeds. The a major variable with the rocket (and a difference between ours) is the full feathering prop. I don’t know if it’s a good idea to feather it in the air outside of an actual emergency, and even then, there exists the chance of recovering the engine and then being unable to get the prop to unfeather. 

When I had my failure in my m20f, my issue wasn’t making it to the field, it was slowing down to get there. The sight picture at the time of my realization was that I could see the end of the 10,000ft runway and the 1,000ft marks were about in the middle, so I was at 130mph at 200ft and had 2,000ft of runway underneath me. I stood on the rudder, pulled back on the yoke, loaded the wing as much as I could and dumped in full flaps; my passenger made a hand gesture towards the gear handle. I thought “good idea” (for adding drag).

In my practice with my m20f I noted that getting below 100mph before a slip would shorten my glide distance. I’ll say that in spite of that, she kept wanting to pick up speed. As I got just over the field I was back up to around 100mph. I thought “fuck it” and forced it down. It bounced and lost a lot of speed. After a couple more bounces, I’m rolling fast and the field dropped out from under me. It was a steep downsloping runoff field that, when not covered in 4ft weeds, has the appearance of a dry delta with all the little eroded channels in it. 

As I continued rolling quickly through the weeds I for a brief instant had the sobering thought regarding my own life: “shit. Is this all there is?” I also remembered being ready to dig in a wing and ground loop the airplane if necessary as the end of the field and neighborhood approached. The plane felt like it had settled on its mains so I applied the brakes and came to a stop. 

I had 805 hours total and 600 hours in the Mooney when that happened. 

While I dropped the gear to slow down, the gear ended up buffering my touch down, protecting the airplane and control surfaces, and allowing me to maintain control authority after touching down. If making it was an issue, I would keep the gear up until I was certain I had the field made and then throw in all the drag at once. 

I was trained to imagine the center of the runway as my target, not the threshold, and to make adjustments on short final. 

I teach bleed your speed out of ground effect, even if you're gonna overshoot. Speed carried into ground effect is much harder to dissipate. Aim to touch down at 1/3rd runway point...just what I teach...we're all experienced aviators here.ymmv...

[Shadrach]

1 minute ago, Pete M said:

Progressively shallowed AFTER the 90dg point? Sounds about right.

 

Should have been more specific. Starting at 90degrees.  I compared it to a chandelle because in my experience best results occurred with a constant (steep) initial bank angle with a moderate pull (pitch) that decreases through the turn. I would not pull to the buffet as some have suggested. The goal is merely to use some of the remaining energy to change the aircraft as quickly as possible. At the 90 degree point pitch is more constant as bank begins to shallow with the goal of being level ~180degrees. 

[Pete M]

4 hours ago, Austintatious said:

Sorry ti whoever suggested it, but a 75 degree bank turn is a REALLY REALLY bad idea.  Not only are you going to sacrifice a lot of altitude, you are going to build up a good decent rate that you will have to arrest.

 

 

 

 

 

 

 

Sweet Jesus, how we love to complicate things:) Pitch down, t/o flaps, roll 75dg, pull,er around, land opposit traffic or on airport clear area. You probably wont lose 200ft in the 180. When I had to do it at 500ft I had too much altitude and too much energy left. I pointed at the center of the field, found i was too high, then turned 45dg left to gain seperation from rwy and restablish right dw. At rwy mid point I did another steep 180 and dove for the rwy. Too aggressive. I overshot the rwy and was pointed at the fbo and full parking ramp. I ended up doing a 65 to 75dg banked turn, slightly pitch up with my wingtip 20ft off the ground to get back to the runway. Looked like an airshow act. In short I had more alt and energy than I needed to set up on down wind and make a fairly normal engine out landing. 500ft is more than enough to turn around.

[Johnnybgoode]

A bag of tricks was mentioned. My advice is to add to yours EVERY TIME YOU FLY.

Don't limit learning or practicing to when you are supervised. Know your limits and stick to them but try to stretch them at every opportunity.

Just did the dreaded 180 in my RV-4 a couple weeks ago. Apples and oranges compared to the Mooney, but it was surprisingly easy. Sounds not nearly as dramatic as Pete's. 10,000 hours and a bag of tricks I've been working on for 20 years though.

simple thoughts...

Edited June 3, 2019 by Johnnybgoode

[Austintatious]

35 minutes ago, Pete M said:

Sweet Jesus, how we love to complicate things:) Pitch down, t/o flaps, roll 75dg, pull,er around, land opposit traffic or on airport clear area. You probably wont lose 200ft in the 180. When I had to do it at 500ft I had too much altitude and too much energy left. I pointed at the center of the field, found i was too high, then turned 45dg left to gain seperation from rwy and restablish right dw. At rwy mid point I did another steep 180 and dove for the rwy. Too aggressive. I overshot the rwy and was pointed at the fbo and full parking ramp. I ended up doing a 65 to 75dg banked turn, slightly pitch up with my wingtip 20ft off the ground to get back to the runway. Looked like an airshow act. In short I had more alt and energy than I needed to set up on down wind and make a fairly normal engine out landing. 500ft is more than enough to turn around.

It isn't complicated.  And I personally am not going to recommend people be making 75 degree bank turns at low altitude.  Especially when it is experimentally and mathematically provable that 45 degrees is the optimum.  No maneuver in aviation (aerobatics aside) should require extraordinary pilot skill.  How often does the average pilot make 75 degree bank turns?  and now they are doing it in terrible glider, in an emergency close to the ground with their heart pounding?   45 degree banks, along with being the best point for alt loss vs turn radius are also part of a Private pilot PTS.   This is why 45 is my recommendation.

You are correct in that more than likely there will be loads of energy to burn... but that isnt always the case.  A Hot calm day with a loaded aircraft that only climbs out at 400-500 feet per min might NEED that efficient turn to make it back.  

Energy is easy to kill.... Put out your drag and if that ain't enough, forward slip the airplane.  That is way more effective at killing energy than doing a 1g 75 degree bank.   OTOH, if they are in a situation where they dont have a lot of extra energy, doing the 45 degree bank turn is going to get them turned around in the most efficient way and give a better chance to make it back to the field. 

 

 

 

 

Edited June 3, 2019 by Austintatious

[Shadrach]

5 hours ago, Austintatious said:

It isn't complicated.  And I personally am not going to recommend people be making 75 degree bank turns at low altitude.  Especially when it is experimentally and mathematically provable that 45 degrees is the optimum.  No maneuver in aviation (aerobatics aside) should require extraordinary pilot skill.  How often does the average pilot make 75 degree bank turns?  and now they are doing it in terrible glider, in an emergency close to the ground with their heart pounding?   45 degree banks, along with being the best point for alt loss vs turn radius are also part of a Private pilot PTS.   This is why 45 is my recommendation.

You are correct in that more than likely there will be loads of energy to burn... but that isnt always the case.  A Hot calm day with a loaded aircraft that only climbs out at 400-500 feet per min might NEED that efficient turn to make it back.  

Energy is easy to kill.... Put out your drag and if that ain't enough, forward slip the airplane.  That is way more effective at killing energy than doing a 1g 75 degree bank.   OTOH, if they are in a situation where they dont have a lot of extra energy, doing the 45 degree bank turn is going to get them turned around in the most efficient way and give a better chance to make it back to the field. 

I’m not asking you to recommend anything. Given you’re a glider pilot, I’m interested in your understanding of the maneuver. I’ve done this maneuver many times and I’ve posted what worked best for me.  Since it’s mathematically demonstrable that 45 degree is best, would you mind demonstrating the math? I’m genuinely curious.

40% of my flyign is XC work the other 60% consists of early morning pleasure flights where I regularly practice maneuvers in my bird or another. When I’m in the Decathlon we rarely leave the pattern. My point is that steep turns may seem rarity to you but there are many folks out there yanking and banking before going into the office. I do different things like try to hit my own wake when doing steep 360s or I’ll do turns about a point or practice high key/low key simulated engine out to the threshold. It makes flight reviews easier.

Edited June 4, 2019 by Shadrach

[Austintatious]

53 minutes ago, Shadrach said:

I’m not asking you to recommend anything. Given you’re a glider pilot, I’m interested in your case nderstanding. I’ve done this maneuver many times and I’ve posted what worked best for me.  Since it’s mathematically demonstrable that 45 degree is best, would you mind demonstrating the math? I’m genuinely curious.

40% of my flyign is XC work the other 60% consists of early morning pleasure flights where I regularly practice maneuvers in my bird or another. When I’m in the Decathlon we rarely leave the pattern. My point is that steep turns may seem rarity to you but there are many folks out there yanking and banking before going into the office. I do different things like try to hit my own wake when doing steep 360s or I’ll do turns about a point or practice high key/low key simulated engine out to the threshold. It makes flight reviews easier.

And the bold part is why for you a 75 degree bank is no big deal for you.  You practice it regularly, possible at a familiar field.  By all means, you go for it!  My point is that I dont want to suggest to people that may only fly a handful of hours a month doing mostly XC flight that such a steep bank at low altitude is a good idea.  It can be done, of course, but I see little benifit.

 

As for the math.... I am not a mathematician.  Here is an excellent video demonstrating why 45 degrees is the sweet spot WRT turn radius and sink rate.  It is a presentation on turning in thermals, but the information still applies.   In the graph you can see how drastically the decent rate increases and how little the turn radius tightens past a 45 degree bank angle.  Notice the graph ends at 60 degrees with the line nearly going straight down.  This means that you are getting almost NO tighter in the turn but are building an exponentially higher sink rate if you were to increase to 75 degrees.

 

 

Edited June 3, 2019 by Austintatious

[Austintatious]

I would also like to point out that in the graph, the turn radius' presented is at about 55 knots... This results in about a 250 foot radius at 45 degrees (at 60 degrees it is about 175).  At 110 knots it would double to 500 feet @ 45 degrees bank (350' at 60 degrees bank).  This is why I say that if it is prudent/safe at the field, shortly after takeoff, turn 45 degrees off the  runway heading towards the direction with the best land out options.  Preferably downwind if a X wind exist.  Then, when you are about 400-500 feet displaced from center line, turn back 45 degrees to parallel the runway center line.  In the event the engine fails, a 180 degree turn at 110 knots or less and 45 degrees will put you roughly in line with the reciprocal.  This can let you safely lower the altitude at which a downwind return is possible.

 

the reason for preferring the initial turn be downwind if a x wind exist is because this will result in a turn of less than 180 degrees to line back up with the runway.  Think about that for a sec!

Edited June 3, 2019 by Austintatious

[bonal]

This has been a very informative topic and congrats to MS posters for staying on topic. What if is one of my favorite thought processes during all aspects of flight especially on departure as I think it's the most dangerous time we face. I can share my own experience. Back before we got our Mooney I bought a c150 to train in for my ppl.  My wife and I wer taking off with full fuel and a couple bags lets just say max gross. About 300 ft we lost a cylinder and the engine was vibrating so bad that I was worried we were going to shake apart. There aren't too many good options for straight ahead from 28 at home so I started a left turn to get back to the field. I could only get about 14 or 15 hundred rpm so there was some available thrust but we were sinking at around 200fpm. I remember really pushing on the yoke as we banked at 30 degrees. As we all know one of the down sides of a Cessna is the wing hides your view of the runway when making pattern turns so my attention was devided between airspeed heading rate of descent and looking out the window as the trees were growing taller by the second. After about 270 degrees of turn went wings level about 100ft AGL and had the departure end of the runway right in front for an easy right turn to line it up. 

Rwy 28 is a right pattern and I have never done anything but a right crosswind as SOP but the wind was coming from the left as it usually does so my thinking was to turn into the wind for displacement while I had the greatest amount of altitude and energy. Then when I had to make my turn to line things up the tail wind helped me reach the runway with no trouble. Had I done it the other way I doubt I would have had enough of what I needed to make it back. I understand the points made about turning down wind first but if you think about it I would rather have a tail wind helping me get back than a head wind fighting me when I am closer to the ground.

its clear that a lot of choices have to be made very very quickly and instinctively when things happen so close to the ground and I think we can all agree is no matter what always keep flying the airplane 

Great discussion every one 

[PT20J]

6 hours ago, Shadrach said:

Since it’s mathematically demonstrable that 45 degree is best, would you mind demonstrating the math? I’m genuinely curious.

Ross, it’s in Dave Roger’s paper cited earlier in the thread. And you really should get the 8KCAB out of the pattern - it’s fun there, but funner doing loops and rolls and such

[Shadrach]

13 minutes ago, PT20J said:

Ross, it’s in Dave Roger’s paper cited earlier in the thread. And you really should get the 8KCAB out of the pattern - it’s fun there, but funner doing loops and rolls and such

We do on occasion. I fly it so little that I feel obliged to work on landings whenever I have an opportunity.  I’ll review Mr. Rogers paper and figure out what I’m missing. 

Edited June 4, 2019 by Shadrach

[carusoam]

Thanks for the great input from those that have had the experience...

1) Thoughts on practicing 75° banks... that is just beyond the 60° normal bank that I usually limit myself to... 2g 

2) Practicing at altitude... safe, but it may be a challenge to detect some of the speed and altitude changes...

3) Has Anyone used the CloudAhoy app to capture what actually happens in the practice of this? My memory for that much detail over a few maneuvers isn't that strong...

4) How does the plane handle flying so slow, pulling 75°...  how much nose down attitude is required to avoid stalling the plane?

5) Oddly enough my POH only covers the effect of stall speeds at 60° and level flight...

 

I would really like to get more detail regarding effect of less than 1g turns... (unloading the wing)

 

PP thoughts only, just asking, not intending to fly low level aerobatics in a Mooney...

Best regards,

-a-

[Yetti]

someone is going to correct me, but I would say more Mooney pilots crash on downwind to final or base to final turns than engine out take offs.   The landing phase and turn back phase have similar features.  Slow flight low to the ground. straight ahead is the always the best option.

[Hank]

4 minutes ago, Yetti said:

someone is going to correct me, but I would say more Mooney pilots crash on downwind to final or base to final turns than engine out take offs.   The landing phase and turn back phase have similar features.  Slow flight low to the ground. straight ahead is the always the best option.

More pilots total. Don't see us as a group performing any better, although we don't seem to land short very often. "Crashing" short is a whole 'nother ball game.

[Yetti]

2 hours ago, Hank said:

More pilots total. Don't see us as a group performing any better, although we don't seem to land short very often. "Crashing" short is a whole 'nother ball game.

So the impossible turn is possible, it is not possible with the standard set of pilot skills that cannot keep from crashing performing a standard landing pattern.

 

[Hank]

2 hours ago, Yetti said:

it is not possible with the standard set of pilot skills that cannot keep from crashing performing a standard landing pattern.

 

Hence the name . . . Too many failures . . . .    High time pilots, low time pilots, private pilots, commercial pilots, airline transport pilots, even Mooney Corporation pilots . . . . .

Edited June 4, 2019 by Hank

[Cyril Gibb]

Regarding the turn back vs. straight ahead preferences.  One topic that hasn't been broached is the probability of outcomes.  Based on experimentation, I know that I can turn back with even sloppy performance to at least the airport environment from 800' agl.  Although it's possible to do it in 300', I doubt I'd be successful... maybe yes maybe no.  I'll practice that.

If I lose an engine out of Toronto Island Airport (CYTZ) other than in the summer, the probability of survival straight ahead is close to nil due to hypothermia. If it isn't summer, survival is nil.  If it fails at less than 300-400 feet, probably still within the airport environment, I'd be able to do a 90-100 degree turn to get me on to the airport clearway somewhere.  If it fails at >800', I should make it back. The grey area in between is the question. 

In the case of CYTZ in the cool months even the slim chance of a non-fatal turn back from a low altitude is still preferable to the alternative.  I've found the discussion to be thought provoking.  Before this, I'd just plan on which direction to turn on engine failure to be the most favorable off airport spot.  I'll now plan before takeoff which direction to turn on engine failure (into the crosswind) and adjust my turn back yes/no critical altitude to be the most survivable based on the relative risks.

As @Hank said above, the time to determine the critical altitude is before you take off.  No need to think, just follow the plan. 

[steingar]

Used to be I took off toward fields and the decision was easy.  Now I take off into neighborhoods.  Still, I'll hurt fewer people with the aircraft under control than not.