Engine failure turn back.

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atypicalguy

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Some comments.

A turn to runway 30 seems obvious, but if there was a significant crosswind component from the right, a turn into the crosswind would have been a good decision.

His turn was at a bank of approximately 30 degrees. The most effective return to the runway turn will be closer to a 60 degree bank for most airplanes.

Simply getting turned back is only half of the challenge; getting slowed down before the end of the runway can be difficult.

If one is gong to turn back, one needs to have practiced the turn under the conditions that will exist when having to do it for real. Airplane weight and temperature are big factors. Know the minimum altitude/airspeed from which you will make the turn. The direction of turn should be planned before takeoff. Consider your passengers. If you make a turn from minimal altitude, at a 60 degree bank, you will frighten the passenger. Do you know what the passenger will do? Screaming is OK, grabbing the controls or the pilot is bad.

Not many pilots have seen the ground at less than 200 feet altitude in a 60 degree bank with the nose way down. Be aware that things look different when maneuvering down low. Again, practice under controlled conditions is the route to success.

No, I am not recommending that you try it.


BJC
The best angle is 45, as close to stall at that angle as you dare.
 

964SS

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In sailplanes we do these as part of training at 200’. However, we also have 15 meter wings and glide ratios north of 35:1. Lol
Pitch for best glide and always turn into the cross wind so as not to make the impossible turn any larger. Better yet, forget about the aircraft and save your butt by landing ahead.
 
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radfordc

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Technique: Unconventional Wisdom
"For starters, what bank angle should be used? Safety suggests a shallow bank angle. The problem is that a shallow, large-radius turn displaces the airplane so far from the extended runway centerline that a return to the runway becomes less likely. Although a very steep bank angle substantially reduces turn radius and keeps the airplane closer to the runway, the associated rise in stall speed is unacceptable.

The optimum bank angle appears to be a compromise, 45 degrees. This prevents excessive lateral displacement from the extended runway centerline and results in only a 19-percent increase in stall speed (from 55 to 65 knots, for example)."
 

tallank

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I know this is an old thread but it brings back with my cfi told me when practicing emergencies. The moment the engine quits the insurance company now owns the plane, worry about yourself.
That is a good one. Another one, of all the instructors I have had, and I have had a lot of them, only one gave me the best advice ever: "If in doubt, Don't". Go with your first thought, do something else. This will help with the "go home itis" problem.
 

BJC

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Although a very steep bank angle substantially reduces turn radius and keeps the airplane closer to the runway, the associated rise in stall speed is unacceptable.
The 60 degree bank that I use also includes significant nose down attitude. It is useful when departing on runway heading. Where it is acceptable, I turn about 15 degrees downwind just after liftoff.

We have discussed this at length in another thread; full details of various techniques can be read there.

Key message: practice extensively at altitude, then work down lower. Seeing nothing but ground in the windshield in the turn can be disconcerting unless you have experience at low level aerobatics.


BJC
 

tallank

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Technique: Unconventional Wisdom
"For starters, what bank angle should be used? Safety suggests a shallow bank angle. The problem is that a shallow, large-radius turn displaces the airplane so far from the extended runway centerline that a return to the runway becomes less likely. Although a very steep bank angle substantially reduces turn radius and keeps the airplane closer to the runway, the associated rise in stall speed is unacceptable.

The optimum bank angle appears to be a compromise, 45 degrees. This prevents excessive lateral displacement from the extended runway centerline and results in only a 19-percent increase in stall speed (from 55 to 65 knots, for example)."
A shallow bank angle takes longer to make the turn and you lose more altitude than you will with a steeper angle. Go out and take some measurements of the altitude lost in a 360 degree turn at different bank angles, and do it for a near 60 degree angle also. Very hard to hold a constant speed at near 60 degrees. You will find that you are gaining speed and therefore will not stall.
 

tallank

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The best angle is 45, as close to stall at that angle as you dare.
NO! You need to be at best glide speed or slightly faster. Near stall you are on the back side of the curve and losing more altitude and getting less distance.
 

tallank

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What airplane, and how many have you done in practice at 60 degrees?


BJC
I have done it a 60. Lost less altitude than I did at 45 degrees. You will not stall. You should be nowhere near stall speed. Best glide speed + and at 60 degrees you will be gaining speed due to the amount of back pressure required trying to maintain your chosen airspeed. This is with gliders and my RV6.
 

trimtab

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A lightly loaded 172 needs 400' to get the job done most of the time. A fully loaded 182 can barely get the job done at 600 feet from Vx, and that's while executing eye-popping maneuvers that most pilots have never even attempted on purpose. Total failure on departure at Vx requires going to zero g and staying there until the nose is pointed down as steeply as a full stall recovery...because at Vx, stall is less than two seconds away. Roll rates are to the stops to make it happen. At 600', you will have less than a few wingspans of altitude to straighten out, flare, and touch down. After all this, my personal choice would be any other option, given that in the practices, I was convinced my odds would have been about 70:30 for a landing without serious injury at full gross. I think my odds in a lot of other terrain with less turning would be much better.

As for speed, Vx loses markedly less altitude hands down. It's real, not just theoretically obvious. It's easy to test this for yourself at altitude. I'm not sure why the recommendation is for best glide speed...perhaps in the interest of stall avoidance.
 

TFF

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First every airplane is different. How much airspeed you loose in the turn and how much glide does the plane have. I know an Ercoupe will go from 110 to 60 under power with a tight climbing turn at full power. That tight a turn no power might make the non stalling plane stall. At least not fly. The more aerobatic and clean the plane, the better off you are. At some point, you just split S back, right? A glider you just call a down wind. A Zenith 701 I bet is a management nightmare. An auto in a helicopter is much easier to manage.
 

atypicalguy

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What airplane, and how many have you done in practice at 60 degrees?


BJC
I think one problem historically is that people are using anecdotal experience to attempt to answer what are in many cases mathematical or at least empirically verifiable questions, e.g. what is the best turn roll angle for trying to get back.

The answer here is that 45 is the best angle for pretty much all airplanes. 60 degrees results in excessive risk of stall/spin. Answering the question does not require any experience. It requires reading the research that has been done on the topic by astronauts and ATPs with phds (see links below).

Of course, whether you can make it back at all depends in large part upon whether your climb slope is steeper than your plane's glide slope and things like headwinds. But the best angle is still 45 regardless.



I would highly recommend this EAA webinar on the subject also: EAA

Maybe someone can do a 60 degree bank, but most everyone who tried over 55 in the naval academy simulator died regardless of experience level and the math does not support it either.
 

Dan Thomas

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The hard stuff of physics and math:

1618769643368.png

Look at that increase in load factor and stall speeds between 45° and 60°. The average pilot, and most of us are average pilots, believe it or not, will get into serious trouble at 60 degrees. BJC practices this stuff and knows his airplane thoroughly just from doing aerobatics and accelerated stalls in it. Most of us never tackle that stuff. Add in the overwhelming temptations to hold the nose up to stretch the glide, and to skid that turn to tighten the radius, and you have the classic killer stall-spin crash.
 

BJC

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The criteria for success in the paper:
The experimental research was conducted in a fully instrumented modified GAT-IVS simulator configured to correspond to a light (1600 lb) fixed gear, fixed pitch GA trainer. The simulator has motion but does not have a visual display. The only visual clues available to the pilot were a horizontal line and the letters N,S,E, and W for North, South, East, and West painted on the room walls. Thus, the flights were `essentially' performed on `instruments'. This also accounts for the somewhat arbitrary, but practical and reasonable, criteria for a safe landing. These were defined as: maximum decent rate less than 2500 fpm, rate of decent at touchdown less than 500 fpm, wings level +-5 degrees below 100 feet altitude, turn of at least 175 degrees completed above 100 feet altitude and maximum bank angle less than 55 degrees. The tests were performed in the no wind condition.
My comments, and experience, are wrt VFR flight.

A 45 degree bank coordinated 180 degree turn in no wind will leave the airplane travelling parallel to the runway, but too far from it, laterally, to land on the runway. The restriction of wings level below 100 feet prohibits additional S turning to align with the runway.

Did he actually evaluate 60 degree banked, steeply descending turns? They leave the airplane much more closely aligned with the runway, requiring less flightpath distance, and less of an S turn (at very low AGL) to land. It does require experience flying with the controls at, or near, the stops, maintaining airspeed just above stall by trading altitude to maintain speed in the turn (extreme nose down attitude) and it takes experience looking outside at extreme attitudes without reference to the horizon.

I’ve done several hundred from minimum AGL, with a power pull and a one second delay before control input. I flew many at 30, then 45 and then 60 degree banks. I always was able to land from the 60, but not from the other two, because I was too far displaced from the necessary runway alignment.

Note that more stall - spin accidents occur when turning crosswind on takeoff than on turning base to final. It is harder to induce a spin from a 60 degree bank with the nose well down than it is from a 30 degree bank uncoordinated turn.


BJC
 

BJC

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the overwhelming temptations to hold the nose up to stretch the glide, and to skid that turn to tighten the radius, and you have the classic killer stall-spin crash.
Yup, those are killers.

Keep in mind that there is no attempt to maintain altitude in the 60 degree banked turn; to the contrary, the nose will be way down. (The windshield view will be full of trees or dirt, with no horizon for reference.) The available lift is used to change direction, and the cost is altitude, but the benefit is a shorter flight path and less of an S turn for runway alignment.


BJC
 
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Rhino

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This is probably the scenario I fear the most. My airpark is at an airport with several long runways to choose from, and ample straight ahead or near straight ahead landing possibilities for almost every one of those runways. Most of the other airports nearby have a similar arrangement. I plan to stick to that setup until I become more experienced with my plane and do lots of practice for engine failures (among others). I'm also happy that I chose an aircraft that will probably be well above 200 feet before I even run out of runway at those airports. It's another one of those "I didn't really need STOL, but I'm glad I have it" moments.
 

Vigilant1

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Keep in mind that there is no attempt to maintain altitude in the 60 degree banked turn; to the contrary, the nose will be way down.
I think that is key. The wing won't stall unless the critical AoA is exceeded, and "unloading" helps prevent that (as a bonus, the roll to 60 degrees can be appreciably faster with less "g" ). But practice at altitude would be important to safely master the maneuver, and then practice nearer the ground would likely be important to help a person get used to the sight picture ("The windshield view will be full of trees or dirt, with no horizon for reference") so they gain confidence and will be able to grit their teeth and follow through with the plan.
Unless the pilot knows he/she has enough energy to make the turn and hit the runway at an acceptable sink rate and has practiced doing it, choosing the cornfield off the nose may be the best option (if available).
 
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