Testing the Impossible Turn

But if you don't know what you can do, certainly don't try in an emergency situation. My Motto for emergency landings is "make them much like your normal landing as possible, try as little new stuff as possible during an emergency."

Brian


Exactly. This is why I make just about all landings "Short field" landings.

What's the point of exercising lots of float down a runway?

Touch down with minimal speed required to maintain aircraft control. The End.
 
Maybe you can point out the flaw in this reasoning?
1. Pilots will attempt this maneuver with no previous effort to master it - often to a bad result. The lure of that runway is strong.

Agreed.

2. There are many cases when this turn just won't work well.

Agreed.

3. There are cases when it would be well within the skills of the average pilot with training to perform a turn-around with a high degree of success - and that is demonstrable though maybe without the smoke and screaming from the back seat.

In the context of it being within the skill set of the average pilot, I largely disagree. The simulated practice of a demanding maneuver a few times at 3,000 feet is not the same thing as having to execute it at 300 feet with all of the attendant things that would/could be present that cannot be simulated at altitude. Even the FAA and AOPA ASF recommend against turnbacks.

4. For pilots to develop the judgement to make this decision on the fly, training would be essential.

"On the fly" is getting closer to the real point, namely: the pilot would need to calculate the altitude required for a successful turnaround before each and every takeoff, factoring in measured performance factors for the airplane (not the generic performance numbers in a POH, but numbers measured specifically for the specific airplane), the exact weight of the airplane at takeoff, the winds, the OAT, the runway length, etc., etc., etc.

For a detailed treatment of this problem, I refer everyone to John T. Lowry's book, "Performance of Light Aircraft" by AIAA. In it, Lowry concludes (for straight outs with total engine failures):

"it is certainly not an 'impossible' turn; just an unlikely one.... Lightly powered airplanes with their shallow climb angles, tend to get too far away from the runway to be able to make it back."

I agree with Lowry.

No one is suggesting that you should have to perform this maneuver to get a private cert but you and I both know that pilots need better stick and rudder skills and judgement than is taught by the primary training they get. Shouldn't pilots aspire to this level of skill and shouldn't there be competent instructors that know how to teach something other than rote numbers and rules of thumb? Isn't that how you make your living?

I agree, but it's not the realities of the situation. And yes, I do make my living trying to make better, safer pilots. And rest assured that if I could guarantee the same level of success to my clients by teaching them turnbacks as the straight-aheads have afforded since the dawn of powered flight, that's all I would teach. And I would charge those pilots a percentage of their life insurance/aircraft hull values to show them the technique (insurance companies would probably mandate such training, too).

I'm actually a little conflicted by your take on this issue. In the drama and haze and mental difficulties of the inadvertent spin environment, you prefer NRC because you perceive it to be the easiest method for successfully dealing with that type of emergency all things considered, yet here you advocate the most difficult and demanding option vs. the easiest and consistently safer one for pilots to implement in a critical and stressful situation.
 
In the context of it being within the skill set of the average pilot, I largely disagree. The simulated practice of a demanding maneuver a few times at 3,000 feet is not the same thing as having to execute it at 300 feet with all of the attendant things that would/could be present that cannot be simulated at altitude. Even the FAA and AOPA ASF recommend against turnbacks.

Rich -- who's advocating a turnback at 300' AGL?

I've been pretty consistent in arguing throughout this thread that even 500' AGL isn't enough -- but above 500' AGL it may work in my Chief.

That said, I also begin the turn to downwind at 500' AGL. By the time the turn is complete I'm at 650' or more.
 
Rich -- who's advocating a turnback at 300' AGL?

No one (yet) Dan, no one -- I was merely using 3,000 feet and 300 feet to illustrate the point that pilots tend not to perform with the same degree of confidence, finesse, and consistency when executing maneuvers at high altitude vs. low altitude.

I also appreciate the fact that your experiment has resulted in you being more defensive in terms of how you fly your traffic patterns.
 
No one (yet) Dan, no one -- I was merely using 3,000 feet and 300 feet to illustrate the point that pilots tend not to perform with the same degree of confidence, finesse, and consistency when executing maneuvers at high altitude vs. low altitude.

I also appreciate the fact that your experiment has resulted in you being more defensive in terms of how you fly your traffic patterns.


OK, but then we have this uncertain regon between "Plenty of room" and "Too close."

Shouldn't we have a hard line where that might be? After all, if we've tried it and learned it can't work, we'd be more likely to program that option out.

Analogy:
In the Army I trained with MILES -- a laser-based system to help replicate direct and indirect fire shooting.

For most soldiers, that shriek going off really ruined a day. I always took it very hard -- after all, if it were real bullets, I'd be dead (and so would my crew when MILES on tanks).

So, you learned what you could and couldn't get away with. Some of the training reinforced bad habits (leaves will stop MILES beams but not real 120mm rounds, etc), but mostly it helped you establish the boundaries, make cover and concealment habit, and peering over the edge really stupid.

I see a similar problem here. The engine-out on takeoff is bad mojo. We want to avoid that possibility through prevention -- check fuel ON, water removed, maintenance done, etc -- but be prepared if faced with the preventable.

How do we prepare? Easy -- we practice in different scenarios in a (relatively) benign environment. This should reinforce certain behaviors while extinguishing others.

I think that practicing a power to idle 180 turn at altitude is an illuminating exercise every pilot should do in an airplane he/she flies regularly. I don't think that Vso*1.1@ 60 degree bank is required for this manuever until the pilot is at a proficiency level that this sort of flying is routine.

This is very similar to the "Don't fly low" advice given to all pilots.

Then, inevitably, they go fly low over the house or the country club or whatever.

Most survive and no one is hurt.

Most.

So -- should we simply assume that our advice is being heeded?

Or should we take the daredevils out and show them what might happen in a zoom climb while looking back to wave?

Or how close those trees get when you are in an ever-steepening bank becasue you're waving and not maintaining back pressure and haven't increased throttle?
 
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I'm actually a little conflicted by your take on this issue. In the drama and haze and mental difficulties of the inadvertent spin environment, you prefer NRC because you perceive it to be the easiest method for successfully dealing with that type of emergency all things considered, yet here you advocate the most difficult and demanding option vs. the easiest and consistently safer one for pilots to implement in a critical and stressful situation.

I'm not advocating that more pilots should consider this maneuver - only that they should be adequately trained to make an informed decision and execute on it if it should ever happen. As you said, pilots are going to try it anyway and if they have some training, not to encourage it, but to have the judgement to know in a particular case that it won't work, or it will - then that's got to be a good thing.
 
I'm not advocating that more pilots should consider this maneuver - only that they should be adequately trained to make an informed decision and execute on it if it should ever happen. As you said, pilots are going to try it anyway and if they have some training, not to encourage it, but to have the judgement to know in a particular case that it won't work, or it will - then that's got to be a good thing.

Right -- sometimes the purpose of "training" is to prove something can't or shouldn't be done.
 
Right -- sometimes the purpose of "training" is to prove something can't or shouldn't be done.

The local instructor I know who teaches this maneuver says that after receiving instruction at altitude, a fair percentage of his students conclude that it is not for them. In addition to gaining a more realistic outlook on a maneuver that they previously had only thought about, I feel that they have in the process received training that teaches better airspeed control, which is bound to benefit them in straight-ahead emergency landings as well.
 
I think I said somewhere back near the beginning of this thread that the whole discussion is moot if you can't hit your spot, power off, in an emergency return to earth. If you're high, you can always slip to get down but if you're low you're coming down short of your spot. Too high is always better than too low if you know how to drop in a big slip.
 
I don't think that Vso*1.1@ 60 degree bank is required for this manuever until the pilot is at a proficiency level that this sort of flying is routine.

Isn't Vso the stall speed in the landing configuration? Don't you mean Vs?

Or are you putting the flaps down during this maneuver?
__________________________

Rogers recommends 5% above the stall speed at a 45 degree bank, but he's talking about the stall speed that applies in the bank. He assumes a constant rate of descent, so for 45 degrees the load factor of 1.41 would apply, and the stall speed would be 1.19 x Vs. So that would be

Vturnback = 1.05 * 1.19 x Vs = about 1.25 x Vs

Thus the airspeed he recommends for a 45 degree bank is actually higher than the airspeed you mentioned above for a 60 degree bank. In your airplane it would amount to about 45 mph.

I note, however, that the speeds you said you have actually tried (in posts #1 and #86) are between 1.3 and 1.6 x Vs. If you're only getting 300 feet of altitude loss, it sounds like doing it closer to stall speed would not serve much purpose.

I still think you would be better off at 45 degrees though. Whatever margin above stall you choose, I don't see any way of getting around the Rogers-Jett analysis on that point.
 
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One of several problems with this maneuver is that other than turns on a point, I don't know any other that is as affected by winds. The "choice" between teardrop and 270/90 will be made more by winds and related factors than the pilot, for example. In the studies referenced throughout this thread, wind was mostly eliminated as a variable.

In the last month alone, I have performed T/0s and landings with winds in excess of 25MPH. The difference between touching down straight ahead and downwind would be 50MPH which is a lot of energy. Assuming 50MPH stall, I would have "crashed" at less than 30MPH or "landed" about 76-80.

I have also landed with effective crosswinds of ~20MPH. Depending on whether or not the crosswind was up or down, the amount of turn required to realign with the runway would be substantially different. The difference would be greater with smaller bank angles.

Considering the number of RLOC accidents in the database, most of us are not ready for this maneuver in most cases.
 
... Assuming 50MPH stall, I would have "crashed" at less than 30MPH or "landed" about 76-80....
And which sounds better? :)

The stronger the headwind, the greater the likelihood of making it back to the airport, so I'd call a strong headwind a good thing. And remember, of course, that nobody put another airport on the extended centerline of your departure airport, so a straight-ahead landing is likely to require some maneuvering and turning and slipping and gliding, and the direction of landing isn't necessarily going to be the one that's most favorable for the winds (e.g. departing with a left cross-wind, but the best field is to your right).

But there are a number of reasons why this maneuver isn't very compatible with super-short runways. You're less likely to make it back, and if you do make it back you're more likely to get into trouble with a downwind landing.
I have also landed with effective crosswinds of ~20MPH. Depending on whether or not the crosswind was up or down, the amount of turn required to realign with the runway would be substantially different.
Assuming you have the presence of mind to turn into the cross-wind (more likely if you make mention of this as part of your pre-departure brief), then a cross-wind is a good thing, and the worst-case scenario is no wind at all. The stronger the cross-wind the closer you stick to the extended center-line and the less change of heading is required to perform your teardrop.
-harry
 
Got to sorta practice this yesterday (Thread here)

Summary: Training took over. As soon as I heard the power change I had my field in sight, did a turn to lose altitude. When I knew I had residual power, made for the airport, kept it high, had an out if the airport wasn't made, and slipped aggressively and wheelied when it was the only option.

Practice engine outs, practice slips, and make sure you know how your airplane will fly at reduced power settings.
 
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I'm actually a little conflicted by your take on this issue. In the drama and haze and mental difficulties of the inadvertent spin environment, you prefer NRC because you perceive it to be the easiest method for successfully dealing with that type of emergency all things considered, yet here you advocate the most difficult and demanding option vs. the easiest and consistently safer one for pilots to implement in a critical and stressful situation.

In both cases, I'm suggesting that pilots should seek training and that the training should be available to them. Average pilots can learn aerobatic upset/recovery and invoke it someday when an upset happens. For that training, I prefer a method that is more "fool proof" than PARE or Beggs. For this thread, I'm just calling out the notion that this isn't an "impossible turn" in many instances and instruction should be thorough enough for a pilot to have something to call on in the emergency. If they've been exposed to it in training, it has to be a benefit in making that decision to turn back or not with more successful results. I'm going to say again though that training and practice at simulated engine out landings goes a long way toward the tools needed improve the outcome of this emergency.
 
In both cases, I'm suggesting that pilots should seek training and that the training should be available to them. Average pilots can learn aerobatic upset/recovery and invoke it someday when an upset happens. For that training, I prefer a method that is more "fool proof" than PARE or Beggs. For this thread, I'm just calling out the notion that this isn't an "impossible turn" in many instances and instruction should be thorough enough for a pilot to have something to call on in the emergency. If they've been exposed to it in training, it has to be a benefit in making that decision to turn back or not with more successful results. I'm going to say again though that training and practice at simulated engine out landings goes a long way toward the tools needed improve the outcome of this emergency.

This only becomes an "aerobatic" exercise when the pilot maintains a very steep bank at a very slow airspeed.

I think the value of this training in the normally flown airplane is awareness of what is and isn't possible, and the stick and rudder required to achieve the possible.
 
Got to sorta practice this yesterday (Thread here)

Summary: Training took over. As soon as I heard the power change I had my field in sight, did a turn to lose altitude. When I knew I had residual power, made for the airport, kept it high, had an out if the airport wasn't made, and slipped aggressively and wheelied when it was the only option.

Practice engine outs, practice slips, and make sure you know how you're airplane will fly at reduced power settings.

This is why I teach power off wheel landings. They are harder to do, but this situation is the best reason I can think of that you might NEED to do a wheel landing in most small taildraggers.

I know a fellow Flight Instuctor that did the exactly the same thing when then engine quit on the Aeronca 7AC he was flying while doing stalls, The engine idle speed was set to low.


Brian
 
I started this thread with a description of some attempts I made to do a 180 with power to idle to see how much altitude I lost: partly to test my technique, partly to test the airplane.

It has changed how I fly patterns. I begin the turn to crosswind sooner, and make one continuous turn (no squared off patterns).

But this is for a particular airplane at a specific airfield. My options straight ahead are very limited, the engine is 70 years old, and the airframe isn't designed for power-off flight.

So it is important for me to know ahead of time that there is no way I can make it back before I reach some altitude, and reinforce that once in a while.

Above that height it becomes possible, without unusual attitudes, skills, or maneuvers.

Dan,

I have enjoyed your posts about learning the limits and the possibilities in the Chief. Your learning curve reflects mine. Few folks here will understand the flying characteristics of the A-65, and I applaud you for exploring them.

Henry and I have both explored the impossible turn at our home field since our choices of a "straight ahead" are very limited. Our airplanes are very agile and climb quite well. At altitude, our limit for the turn is 400 ft. However, in an actual engine out, the biggest limitation is pilot reaction time. Those are precious seconds, so our true limit will be somewhat higher.

Frankly for us, 400 ft finds us still over the runway at the home field, so there are other challenges and decisions to be made.

I was lucky that my primary instructor was a crop duster pilot at one time as well as a jet jockey. I am also lucky that we fly small, light airplanes that have the wing span of a C-172. Lots of glide.

The A-65 that you and Henry fly behind, and the C-85 that I use are prone to some issues, stuck valves and carb ice being the most common. I recommend that you keep practicing. It may save your hide some day, and I already know that it has saved mine! :D

BTW, you suggest that your climb is poor. It's possible you have a poor engine/prop combination.

Or your problem is that you fly a Champ. :rofl:

Luscombes are known for the best performance with the fewest ponies. :yesnod:

Deb
 
The A-65 that you and Henry fly behind, and the C-85 that I use are prone to some issues, stuck valves and carb ice being the most common. I recommend that you keep practicing. It may save your hide some day, and I already know that it has saved mine! :D

BTW, you suggest that your climb is poor. It's possible you have a poor engine/prop combination.

Or your problem is that you fly a Champ. :rofl:

Luscombes are known for the best performance with the fewest ponies. :yesnod:

Deb

Deb,

Actually, my Chief is the Lycoming O-145-B2 variant. While most Aeroncas ended up with Continentals, early versions allowed a choice of powerplants.

The only advantage of the Lyc was the air intake -- it feeds through the oil sump greatly reducing the likelihood of carb icing. The O-145 was Lycoming's first foray into the aviation market, and came out in 4 different variants, as well as a geared model.

Of course the warmed air also means reduced horsepower. So even the 65 isn't a true "65."

I agree that it's important to test the limits of these airplanes, as the possibility of failure is a bit higher simply because the systems are so simple, old, and lack the decades of engineering knowledge amassed after they were designed and built.

We also don't have other systems taken as standard -- starters, multiple fuel tanks, flaps, and nose gear.

Larger singles actually present a greater hazard with a powerplant failure because there's lots of mass to decelerate. Min controllable airspeeds are also higher.

Whereas in a lightweight fabric and tube taildragger, there’s less mass, and more gradual crumpling if and when there’s an impact at generally slower speeds.

By the way -- I was able to test all this theorizing yesterday when I had a partial power loss. Thread here
 
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This is why I teach power off wheel landings. They are harder to do, but this situation is the best reason I can think of that you might NEED to do a wheel landing in most small taildraggers.

I know a fellow Flight Instuctor that did the exactly the same thing when then engine quit on the Aeronca 7AC he was flying while doing stalls, The engine idle speed was set to low.


Brian

I like my three-points, but Henry lands his 8A (A-65) on the mains with no power. If I practice my wheel landings, I don't add power either. We approach both types at the same speed, but a different attitude.

He once won a spot landing contest with a wheelie. That's hard to do in a Luscombe.

Deb
 
I like my three-points, but Henry lands his 8A (A-65) on the mains with no power. If I practice my wheel landings, I don't add power either. We approach both types at the same speed, but a different attitude.

He once won a spot landing contest with a wheelie. That's hard to do in a Luscombe.

Deb

I prefer 3 points with most light taildraggers I fly. However my Scout, Stinsons, and my sailplane seem to like wheel landings better. One certainly can 3 point them, they just seem to land better with wheel landing.

I haven't had the pleasure of flying the Luscombe yet so I can't say one way or the other.

I did once win a spot landing contest an a Aeronca 7AC when I came in too high and was going to over shoot with the 3 point, so I changed to the wheel landing and ended up winning it. Came in 2nd in the Flour bombing that day as well.

The trick to nice power off wheel landing is typically adding 5 to 10 mph to the approach speed this give you the flat attitude and the float needed to set it gently on the mains. Plus it is representative of the situation Dan had where you need to set it down but are too fast to 3 point it.

While I don't recommend or practice it, I know that it usually isn't too hard to apply brakes once the plane is rolling on the mains if you need to get it stopped.


Brian
 
Deb,

Actually, my Chief is the Lycoming O-145-B2 variant. While most Aeroncas ended up with Continentals, early versions allowed a choice of powerplants.

Oh. The Luscombe 8B has that engine. It's a dog. Don't mean to hurt your feelings, but it's a fact.

Fly it and start saving your pennies for a conversion.

There's no need to keep it other than for purists' reasons.

Henry's newly overhauled A-65 with a climb prop climbs at 1200 fpm. He cruises at 100 mph.

Deb
 
While I don't recommend or practice it, I know that it usually isn't too hard to apply brakes once the plane is rolling on the mains if you need to get it stopped.

Brian

No braking for the Luscombe unless you like the view from upside down :D.

Deb
 
While I don't recommend or practice it, I know that it usually isn't too hard to apply brakes once the plane is rolling on the mains if you need to get it stopped.
If you have crappy brakes, it's probably not a good idea.

Otherwise, how else can you come to a stop with the tail still in the air?
 
Oh. The Luscombe 8B has that engine. It's a dog. Don't mean to hurt your feelings, but it's a fact.

Fly it and start saving your pennies for a conversion.

There's no need to keep it other than for purists' reasons.

Henry's newly overhauled A-65 with a climb prop climbs at 1200 fpm. He cruises at 100 mph.

Deb


Yep -- the Lycoming 65 is probably closer to a 50 hp.

So I plan ahead. :D

That said, 2500 RPM gets me 85 MPH solo, while burning about 3.5 gph.

It idles great, and starts on the first or second throw.

This engine is the original S/N for this airframe, so I won't part with it. Some purist will want it that way.

In the meantime I'll keep it running and fly it 100 hours a year.
 
No braking for the Luscombe unless you like the view from upside down :D.

Deb

I bet it results in a short rollout, eh?


Seriously (for a moment) when you talk about old (and even new) taildraggers, they all are quite different in how they behave and what works best.

Personally, I REALLY liked wheel landings with brakes in the 120 to deal with crosswinds - land hot with solid controls, plant the mains, steer with brakes. Wind sock looks like it is made of sheet metal and is pointing right across the runway? No problem. Good, positive control every inch of the way. Easier than trying to land something like a Cessna 150.

But if the tail is too light, or you have, um..., less than consistant brakes than it is a whole different animal.
 
I bet it results in a short rollout, eh?


Seriously (for a moment) when you talk about old (and even new) taildraggers, they all are quite different in how they behave and what works best.

Personally, I REALLY liked wheel landings with brakes in the 120 to deal with crosswinds - land hot with solid controls, plant the mains, steer with brakes. Wind sock looks like it is made of sheet metal and is pointing right across the runway? No problem. Good, positive control every inch of the way. Easier than trying to land something like a Cessna 150.

But if the tail is too light, or you have, um..., less than consistant brakes than it is a whole different animal.


I never used brakes until Monday -- was warned not to.

Guess what? Not so bad. The brakes are like bicycle brakes -- can vary from barely rubbing to sorta grabby. Just keep some heel contact with the floor and you won't over-brake.
 
I never used brakes until Monday -- was warned not to.

Guess what? Not so bad. The brakes are like bicycle brakes -- can vary from barely rubbing to sorta grabby. Just keep some heel contact with the floor and you won't over-brake.

Welcome to the dark side.
 
:D

Well, I'll keep that trick in my back pocket. No need wearing out perfectly good brakes when all they're for is holding back (barely!) during runup. :rolleyes:

That's about all I use mine for is a run-up before blasting off - and a power off, bootlegger 180 up to the fuel pump. Brakes are way overrated. Aerodynamic braking is where it's at.
 
That's about all I use mine for is a run-up before blasting off - and a power off, bootlegger 180 up to the fuel pump. Brakes are way overrated. Aerodynamic braking is where it's at.

I don't have much "aerodynamic braking" except for the large amount of induced drag caused by high AoA flight, which is somewhat offset by Ground effect.
 
I don't have much "aerodynamic braking" except for the large amount of induced drag caused by high AoA flight, which is somewhat offset by Ground effect.
A nose-above-the-horizon slip will slow most airplanes very rapidly. It might mean you climb some when you actually want or NEED to go down, but the rate that you drop energy makes it well worth it. You'll want to be familiar with the airplane's slip and stall characteristics.
 
A nose-above-the-horizon slip will slow most airplanes very rapidly. It might mean you climb some when you actually want or NEED to go down, but the rate that you drop energy makes it well worth it. You'll want to be familiar with the airplane's slip and stall characteristics.

Yeah -- I am. I had to slip Monday just to make it to the runway (If I was flying a 172 or other rudder-limited airplane the only choice would have been a spiral -- I was pretty high above the runway).

I think PittsDriver was talking about "aerodynamic braking" in reference to landing (as opposed to wheel brakes).

I'd better have the slip out before I touchdown or things will get interesting in a hurry -- as they will in any taildragger.
 
Yeah -- I am. I had to slip Monday just to make it to the runway (If I was flying a 172 or other rudder-limited airplane the only choice would have been a spiral -- I was pretty high above the runway).

I think PittsDriver was talking about "aerodynamic braking" in reference to landing (as opposed to wheel brakes).

I'd better have the slip out before I touchdown or things will get interesting in a hurry -- as they will in any taildragger.

Sure. But you can blast down a runway at 10 or 15 feet in a level nose high slip and slow very rapidly. More rapidly then you'll likely slow with some wheel-barrow sized wheels and bicycle brakes.
 
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Sure. But you can blast down a runway at 10 or 15 feet in a level nose high slip and slow very rapidly. More rapidly then you'll likely slow with some wheel-barrow sized wheels and bicycle brakes.

Did you read my real-life turnback post?

I kept the slip down to 5' above the runway. Only pulled it out when I could feel it getting very mushy, and just in time. Upwind wheel touched and rolled straight.

Not for the faint of heart and not what I would consider a "normal" maneuver.
 
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