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Engine Failure on T/O - Turnaround Data

turnbank

This has very little to do will stalling speed vs bank angle. Sunrise Aviation is one of the most highly regarded Aerobatic Schools in the world and in addition they have a regular flight school. My understanding is that they teach the turnback maneuver to students. At John Wayne Airport, flying off the secondary runway can put you in a very bad situation regarding engine failure on takeoff.
The other factor people seem to not understand is the type of airplane. The very worst of the singles that can be defined as light aircraft are airplanes such as the A36 Bonanza, the Navion and the Cirrus. They are relatively heavy, high wing loading aircraft. A turnback maneuver that might possibly be sucsessful with a 152 or 172 from 400 ft agl, might very well be unsucessful in a Bonanza or Navion from from 1200'. At least two of the faatal turnbacks in the last few years have been Bonanzas at a very low altitude. Not a chance of sucsess.
 
If you're at best glide (90?) Then it'll take a pretty good G load to stall (same aoa as 0 bank level flight stall)....bank angle has nothing to do with it... Engine out you're definitely not maintaining altitude anyway. I've flown my airplane in a 45 degree bank at 30mph....maybe 0.4g...maybe less...
 
Larry,

The FAA do talk a lot of rubbish at times ;)

In a turn where you are unloading to maintain airspeed the stall is not so rapidly approaching as you may think.

This is why with a competant aerobatic instructor you should practise this at height first, then carefully off the deck so you get the real picture, and it is really different.

The problem I see is the Rudder! If you are not keeping a balanced turn, you become the feature of a nasty video.

Some thoughts, in no particular order.
1. On EVERY TAKEOFF, have a mental brief of what options are what.
2. Climb faster IAS than Vy, kinetic energy is your friend.
3. Practise low speed handling often, at altitude but also carefully close to the ground, do a low level training course, always be doing something to sharpen your skills not be fat dumb and happy.
4. Know Your Aeroplane
5. Remember a good pilot is never surprised by an engine failure, he is always surprised when it doesn't! ;)
6. Know Your Aeroplane
7. If departing a short strip with high trees, climb as fast as you can, I call it aim for the trees and miss!
8. Know Your Aeroplane
9. Know what heights mean you must go pretty much ahead, know your heights for I can have 180 degrees in front of the wings, and know your heights for making any suitable ground behind you, including the runway.
10. Know Your Aeroplane
11. Knowing the close to the ground stuff will come in handy when you have a failure from 10,000' feet too, because when you pick out an airfield or pick out paddock, sooner or later you are in similar territory, so be up to the task, and practise it, and not every two years in a check ride.
12. Know Your Aeroplane.
 
The bottom line....

Before you attempt it in a real emergency, you had better KNOW that you can complete the maneuver.

I flew large scale R/C for many years. They stall and crash just like the full size counterparts. Over the years, I witnessed many "return to the runway" spins, as well as accelerated stalls, such as pulling out of a loop too hard & too close to the ground...........only to feel you're safe, and then see the plane suddenly spin in.

I've seen my friend, miss the ground & almost the end of it all, by the height of sagebrush after he stalled doing a pull up over the runway. Happily, he kept at it until the last second. Note: real plane, not R/C

And just like full size, R/C planes all depend on wing loading for the ease of completing a 180+, or stalling exactly as in the video. Therefor, don't just start executing a 180+ at the last moment, just because you read it can be done on these forums.

L.Adamson
 
Larry,

The FAA do talk a lot of rubbish at times ;)

Hey, don't shoot the messenger! ;) I'm just repeating what the FAA told us at the seminar. :eek:

You have to ask yourself how many pilots do you know who have competed the manuver and lived to tell about it. Real life, not practice. :confused:
 
People seem to think going for Vx or Vy is the smarter thing to do, gain height quickly. The opposite is true, unless you actually have to clear obstacles.

Climb performance does matter a bit, especially on short field takeoffs.

If your climb angle is shallower than your glide angle, there's no point even attempting a turn back because even if you do it without spinning-in, you'll have no possible way of making it back to the runway you took off from.

Wind is important, of course, because a tailwind makes your glide angle shallower and a headwind makes your best climb angle steeper, relative to the ground.

Not so much of an issue in RVs because they climb like maniacs and have low enough wing loadings to glide pretty well too. But your average spam can, with it's lazy climb rate and brick-like glide is in a pretty bad situation on EFATO. It's not surprising that instructors who spend a lot of time in those types think a turn back is a fool's errand.

In gliders in Australia we teach turn backs after simulated aerotow rope breaks at 200' as a pre-solo exercise, part of the emergency procedure training that pilots should be competent in before going solo. Apart from the airspeeds and sink rates (which affect minimum safe heights) there's no practical difference between a glider and any other fixed-wing aerodyne. There's no intrinsic reason to believe it's unsafe in a GA light aircraft, with appropriate training.

- mark
 
Spot On Larry

"Before you attempt it in a real emergency, you had better KNOW that you can complete the maneuver."

KPTK is a towered airport where the tendency is to fly wide patterns.
Whenever possible, I try to conclude a Flight Review by asking the pilot whether he can make the runway from our position in the downwind leg. Mind you, I've already taken him thru a couple of emergency drills during the preceding hour. I've NEVER had anyone say "no" or "I don't think so". I pull the power, announce a failure/no restart possible, and keep the throttle covered with my hand. I've had pilots yelling "throttle, throttle, we're not going to make it!" as they try to pull my hand out of the way and simultaneously start a pitch up while we're still 100 feet AGL. Oftentimes, the pilot will also attempt to continue in a nice, complete pattern with the engine out, giving up valuable altitude in the process. In any event, the exercise is probably the most useful part of the review, as it allows me to get up on my
soapbox and say, " if you learned only one thing today, fly the airplane; and that rule applies whether the engine is running or not".
It never ceases to amaze me what a little stress can do to our thought processes.
Terry, CFI
 
There's no intrinsic reason to believe it's unsafe in a GA light aircraft, with appropriate training.

- mark

I agree with Mark.

There are many regimes of flight that are demanding and requiring of special learned skills (and currency) to accomplish successfully. Flying by instruments in IMC is one. Performing aerobatics is another. Recovering from a spin is another. This does not mean they are intrinsically unsafe...it just means you need training and practice to become proficient in them. And this is exactly the same for performing a turnback at EFATO.

The problem for most pilots who attempt a turnback is that the first time they attempt one is usually just after their engine has failed. In that case the outcome is generally not good. This is the same as a VFR pilot flying inadvertently into cloud and trying to suddenly develop some instrument skills. Once again the outcome is generally not good.

But learning and practice makes for proficiency in all aspects of flight and greatly reduces the propensity for panic, which is in itself debilitating as Terry Kohler has pointed out.

For those who fly out of airports surrounded by totally built-up areas, or surrounded by completely inhospitable terrain, it probably makes sense to practice the turnback manouevre in stages of reducing altitude to achieve total proficiency in a specific aircraft and establish it's "no-go" altitude.

For those who are not proficient in the turnback, the land-straight-ahead rule is likely to produce a better result.
 
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You've got to ask yourself one question...

You have to ask yourself how many pilots do you know who have competed the maneuver and lived to tell about it. Real life, not practice. :confused:
Most of the time it is a mistake. (NTSB)

If it is a mistake, most of the time you won't make it. (NTSB)

Most of the time you won't make it!

Note that an argument can be valid, even if one of the premises is false :eek:

"You've got to ask yourself one question: Do I feel lucky? Well, do ya?" -- Harry Callahan, Dirty Harry - 1971
 
"It is common knowledge that, because of loading, stalling speeds increase with angle of
bank. Take a look at the figures which relate to a typical four-seat tourer in world wide
use (see Table 1)."
Bank Angle Stall Speed Increase (%)
0 deg. 49 knots 0%
35 deg. 53 knots 8%
45 deg. 59 knots 20%
60 deg. 71 knots 43%
75 deg. 97 knots 97%

It aggravates me that this kind of information is always used without the caveat...."this is only applicable if you are maintaining altitude...i.e., loading G's...and increasing AOA in the process"....although they do sneak in "because of loading." Ok, what does that mean? You just have to realize it means: maintaining altitude (or more precisely increasing AOA). Bank angle, by itself, like many have already said, has absolutely nothing to do with stall speed. Its all AOA...thats it, and thats all. Read "Stick and Rudder"...he harps on this all throughout the book, recommended read for all pilots. I feel like this kind of data is published by the FAA for pilots who dont know, nor want to truly understand aerodynamics at a level that all pilots should.

And my rant is certainly not directed at you Larry, my apologies if it came across that way. Just a general rant about this topic.
 
Most of the time it is a mistake. (NTSB)

If it is a mistake, most of the time you won't make it. (NTSB)

Most of the time you won't make it!

Note that an argument can be valid, even if one of the premises is false :eek:

"You've got to ask yourself one question: Do I feel lucky? Well, do ya?" -- Harry Callahan, Dirty Harry - 1971

You only have to make it the first time :)
 
Im airshowing and missed all this. I do understand the pain of watching a video of a loved one perishing. There are videos on the net of accidents that involved friends that i have avoided successfully for many years.....

I do not enjoy these videos at all, but when they are as powerful as this one and clearly show how quickly the situation deteriorates, I believe they have merit.... if i could have edited off the fireball, I would have, but I just posted a link. My thoughts and prayers are with the friends and family.

If I do something stupid in an airplane, you have my permission in advance to post it...

Tailwinds,
Doug Rozendaal
F1 EVO


[ed. Thanks for the update, Doug. I still have the memories of more than one family member call me (in tears) asking me to remove the link to their Dad's crash. I appreciate the permission you give, but I'll respectfully decline. dr]
 
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How many people could 'unload' in those circumstances?

You've just taken off... sudden engine failure... brain/heart go into overdrive... nice safe runway right there behind you... crank in the roll... pull that nose towards safety... passengers indicating displeasure.... feel the imperative to make the runway... roll tighter... pull the nose towards that runway some more... stall warning sounds... if you apply down elevator you will stop turning towards safety... you know stall increases with bank so you know if you just roll out of the bank some you'll un-stall.... apply opposite aileron... downwing aileron goes from up to down suddenly increasing angle of attack on that wing... lower wing stalls... upper wing still lifting...............

Forgive the simplicity of the above, but to unload mid turn requires you to accept that as your bank angle is high and the elevator is driving the turn, that if you relax back pressure (unload) you will stop the turn, that means you 'will not' be making that nice safe runway and that you will be crashing straight ahead at that point regardless of terrain/obstacles, you have no time to do anything else.

I imagine that is one difficult decision.
 
You have to ask yourself how many pilots do you know who have competed the manuver and lived to tell about it. Real life, not practice.

Larry, quite a number, and in fact there was one reported on an engine bug thread here just the other day.

A very good mate of mine, Doug R knows who I am talking about has probably had more engine failures and in some of the roughest places, and only once damaged (very slightly) the aeroplanes.

A good pilot is never surprised when an engine fails, he is pleasantly surprised when it does not!

newt
Climb performance does matter a bit, especially on short field takeoffs.
Indeed.....but did you read what I actually wrote, in summary aim for the trees and miss :rolleyes: Go back and re-read.

If your climb angle is shallower than your glide angle, there's no point even attempting a turn back because even if you do it without spinning-in, you'll have no possible way of making it back to the runway you took off from.
I think you might need to rethink this. Seriously!

Kinetic energy is your friend and will take you a long way, you lose less by converting kinetic than you do from being at a speed from Vx to Vy than you currently believe.

If not, the video I am about to show you is a fake? You cant beat physics, no matter what you say!

I note you talked about angles, most people do not equate angles so well. I have talked about IAS and we should keep it there. By the way best glide speed is a shallower angle than my best climb! ;)

Someone mentioned about not unloading......what?? :eek: Do you guys never do engine failure training.....CHECK FORWARD!!!! And maintain airspeed, in the turn unloading is part of that. Training and practise.

Can I refer back to my last post?

Ok here is the video, first one a normal glide approach into the field not much wind, 850m runway, the first takeoff is simulated at my normal climb out speed, greater than Vy by about 10 knots, and at 500AGL we pull throttle say OHH Bother, about 3 times and into a 45 degree AOB turn, we would have crashed all right, into the fence at the far end!

Second one was the same from 400AGL

So....climbing faster than Vy is a good thing.

http://www.youtube.com/watch?v=uvTUW28JnpY&feature=player_embedded
 
I don't think we're disagreeing

I think you might need to rethink this. Seriously!

Kinetic energy is your friend and will take you a long way, you lose less by converting kinetic than you do from being at a speed from Vx to Vy than you currently believe.

When you're in the turn you're not making headway over the ground (you're inscribing an arc around a stationary point), but you're still losing height.

Because you're banked your sink rate will be measured against the circling polar curve for whatever bank angle you're at, rather than the 1g straight and level polar, so not only are you losing height without going anywhere, you're losing it faster than you would be if you were flying at best glide (or min sink for that matter)

When you come out of the turn, you need to be close enough to the upwind threshold of your runway to reach it from your current height at whatever glide angle you happen you get at your airspeed, wing loading and tailwind.

If your achievable glide angle from that point is steeper than the glide angle required to reach the upwind threshold, you simply will not and can not make it. Aerodynamic impossibility. Make another plan.

So in practical terms, you mustn't attempt the maneuver in the first place unless your aircraft's climb performance is good enough to provide for a climb angle significantly steeper than your achievable glide angle, especially if the runway is short (ie, the distance you need to cover to get back to it is higher)

If not, the video I am about to show you is a fake? You cant beat physics, no matter what you say!

No, I am not saying the video is fake. The video clearly features an aircraft which climbs better than it glides -- exactly what I said was required.

I note you talked about angles, most people do not equate angles so well.

Glider pilots, who are trained in turn back maneuvers and need to demonstrate competence in safely executing them, think in terms of angles a lot. It's how we judge a final glide from 20 miles out and know whether we can make it or whether we need to top-up with another couple of hundred feed in an enroute thermal. It's also the primary positional reference for every engine-off circuit ("What's the angle down to the aiming point?"). With practice it becomes second nature.

A GA aircraft without a functioning engine is a glider. When in Rome... :)

I've done hundreds of turn backs while teaching ab initio glider pilots. A keen appreciation of angles is how you decide right there on the spot whether to continue the turn back or proceed with an off-airport landing. It's important to get it right, because the top wire of the typical sheep-paddock fence is at approximately neck height for a glider pilot; pilots who misjudge approaches and land on the wrong side of the fence tend to get decapitated when they hit it during roll-out.

I have talked about IAS and we should keep it there. By the way best glide speed is a shallower angle than my best climb! ;)

Then you, my friend, are flying an aircraft that is at least theoretically capable of the turn back maneuver.

As I said earlier, the average Cessna or Cub driver probably isn't, especially on a hot day with full fuel.

And since Cessnas tend to be a pretty common training platform, it isn't surprising that the instructors who teach in them warn against attempting turn backs: the aircraft they are most familiar with probably isn't even theoretically capable of successfully carrying it out.

But our RVs probably are. With appropriate training.

Someone mentioned about not unloading......what?? :eek: Do you guys never do engine failure training.....CHECK FORWARD!!!! And maintain airspeed, in the turn unloading is part of that. Training and practise.

Agreed -- unloading is required otherwise airspeed will decay very quickly.

Also remember that best glide speed in a 50 - 60 degree bank (min height loss turn) is higher than the straight and level 1g best glide speed. You'll need to be faster and steeper than you think to carry it out safely, which is one of the reasons why training is so important.


takeoff is simulated at my normal climb out speed, greater than Vy by about 10 knots, and at 500AGL we pull throttle say OHH Bother, about 3 times and into a 45 degree AOB turn, we would have crashed all right, into the fence at the far end!

:)

You'll get back even higher (or, alternatively, be able to safely begin the maneuver from a lower height) if you bank at 60 instead of 45. Makes about a 50' difference in my -6, which is worth 10% of your starting height.

Takes a lot more attention to speed/attitude control and rudder coordination though. Most GA pilots are thoroughly unfamiliar with precise handling at a bank angle like that, and are more likely to (fatally) mess it up if they aren't adequately trained.

- mark
 
Major problem with this assumption

If your climb angle is shallower than your glide angle, there's no point even attempting a turn back because even if you do it without spinning-in, you'll have no possible way of making it back to the runway you took off from.

- mark

This is an erroneous assumption, because it's only true if you assume that your climb begins at the departure end of the runway. More often then not, the runway is considerably longer than required for takeoff, thus when the departure end is reached you already have some altitude in the bank. Think Cessna 150 taking off of a 10000 foot runway(or even a 5000 foot runway).

Skylor
 
This discussion goes on and on, .....so today I went out and collected some real data.

I set up an 80 KIAS, power off glide in my RV6 with CS whirlwind prop. As usual, this produces an 1100 FPM descent. Rolled into an 45-60 degree AOB turn, tried to hold airspeed (1 G), hit the timer and started collecting data.

First off turn rate - 22 secs for a 360 degree turn.
Descent rate 1350 - 1500 fpm

Some subjective comments - very hard to stabilize this flight condition. Nose wants to drop and airspeed tends to increase. Ball requires constant attention to maintain balanced flight.

What does the math tell us?? At this turn rate it will take 16 or so secs to turn 270. In that 16 seconds you will lose 360 feet of altitude IN AN OPTIMUM TURN. Get a little sloppy on rudder, AOB and Airspeed control and that easily goes to 400 - 450 feet required for the turn.

Obviously lots of thing can effect this in real life, - airspeed at entry, winds, pilot skill, runways available, **** in pants, etc. But under stabilized "practice" conditions you need about 400' to make a 270 degree turn - simple math.

Draw your own conclusions. I know mine - below 600 feet AGL, lower the nose and look for somewhere to land in front of the wings!
 
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This discussion goes on and on, .....so today I went out and collected some real data.

I set up an 80 KIAS, power off glide in my RV6 with CS whirlwind prop. As usual, this produces an 1100 FPM descent. Rolled into an 45-60 degree AOB turn, tried to hold airspeed (1 G), hit the timer and started collecting data.

First off turn rate - 22 secs for a 360 degree turn.
Descent rate 1350 - 1500 fpm

Some subjective comments - very hard to stabilize this flight condition. Nose wants to drop and airspeed tends to increase. Ball requires constant attention to maintain balanced flight.

What does the math tell us?? At this turn rate it will take 16 or so secs to turn 270. In that 16 seconds you will lose 360 feet of altitude IN AN OPTIMUM TURN. Get a little sloppy on rudder, AOB and Airspeed control and that easily goes to 400 - 450 feet required for the turn.

Obviously lots of thing can effect this in real life, - airspeed at entry, winds, pilot skill, runways available, **** in pants, etc. But under stabilized "practice" conditions you need about 400' to make a 270 degree turn - simple math.

Draw your own conclusions. I know mine - below 600 feet AGL, lower the nose and look for somewhere to land in front of the wings!

Good data, thanks. Also, you were ready for the maneuver. You thought about what you were going to do before you left home for the airport. That is not how the real world works. The time ot takes an average person to recognize what has happened, formulate a plan to turn around, and implement the turn you have lost a minimum of 3-5 seconds.
 
This discussion goes on and on, .....so today I went out and collected some real data.

I set up an 80 KIAS, power off glide in my RV6 with CS whirlwind prop.
Question - in your above post, does "power off" mean mixture at ICO, or does it mean throttle to idle with engine still running? The performance will be different between these two cases, so conclusions reached from testing (or training) in one case are not necessarily valid in the other case.
 
Yes Kevin, mixture idle cutoff, started at about 5000' spiraling down at a 45-60 degree AOB, trying to maintain airspeed and timing on seconds timer against the altimeter. down to about 3000'.

This is hard enough to do (stabilize the turning descent) all set up at altitude. Not sure how tough it would be at 350' agl for all the marbles with ground rush and some wind thrown in. Good luck!!
 
Draw your own conclusions. I know mine - below 600 feet AGL, lower the nose and look for somewhere to land in front of the wings!

Gary, you're already ahead of the game now by knowing your "no-go" turnback altitude.

In the turnback maneouvre, procrastination is a killer. It results in the loss of critical altitude and an increase in the distance back to the airfield.

You, on the other hand, do not need to procrastinate about whether to turn back or not. You only need to glance at the altimeter and that instrument will make the decision for you instantly. If it reads 600 ft or above, you're going back to enjoy a beer at the hangar. Less than 600 ft and you're making the best of what lies ahead or to the side.

The ability to make an instant decision (by having a known "no-go" altitude) and having confidence in the outcome (by being proficient at the manoeuvre) are the keys to the successful turnback.
 
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While 600 feet is probably safe in most situations, it is not safe in some. I took off at Big Bear california with a full load on a hot day, and there was no way I would be able to turn back to the runway at 600 feet. I think in situations like that you need to be thinking straight ahead as you climb and then look at your situation as you get higher, making a mental shift from straight ahead to turn around when you know you can make it. On that take-off I would have never made that shift, so would have landed straight ahead.

-Andy
 
So what do we do about it?

Ok so we know that the turn back is risky at best and very dangerous. Knowing this, there are two things I will now do on every flight:
1) either do a downwind departure, or at least a crosswind departure, so that I am stay near the airport while low and slow.
2) or have a place to go straight out

I fly from an airport buried in the city, so any off airport landing is dangerous for me or someone on the ground. After seeing the videos, reading the discussions, and having a friend have his last flight trying to turn back a Bonanza, no more straight out climbs for me, unless I am willing to put it down out there. The most important video for me was the 172 departure from a 4500' hard deck; landed short every time trying to make it back from 1000'.

Thanks for the discussion.
 
Most of the time it is a mistake. (NTSB)

If it is a mistake, most of the time you won't make it. (NTSB)

Most of the time you won't make it!

Note that an argument can be valid, even if one of the premises is false :eek:
Flying is dangerous. (NTSB) Maybe its best to stay home on the couch?

Folks, the 180 return-to-runway or abbreviated pattern is like any other skill - you need to practice it if you have any hope of executing it correctly. Stalls, spins, VFR into IMC... you should practice these things, or your chances of making it is low.

Having said that, if you practice, and you make a decision about your alternatives if the fan quits before advancing the throttle, its not an exceptionally risky maneuver. We have plenty of pilots who kill themselves in stall/spin accidents on otherwise normal patterns, but I don't hear anyone calling for the abolition of the standard pattern (oops, "straight in to uncontrolled field" debate, anyone?).

Think about your decision heights in advance, keep the speed above your minimum approach speed and stay coordinated. Those three and practice will go a long way to keeping you flying another day.

I've only done 5 180s in the last year - two practice in the CT @ 500ft (my "standard" DH in the CT) and three in the glider (one unannounced as part of "first flight" reviews, one unannounced during a BFR and one practice; most of these at 250ft). Even so, I still feel a little anxiety when I hear the release pull, but training quickly takes over: Nose down, roll into the turn, yaw string / ball straight, check speed again, look for the runway, stay coordinated, speed, touchdown point, roll out, spoilers as needed, speed, touchdown point, speed, touchdown point.... you get the idea.

In my mind, the 180 is a basic airmanship skill that needs to be taught along with stalls and spins. If you show students what they can and can't do from an early "age", they won't fear the emergency and will instead react properly to it. We treat the "rope break" this way in our soaring club and I think we demystify the 180 this way.

Disclaimer: If you haven't practiced the 180 and don't know the limits of you and your airplane, don't try it.

TODR
 
Bank Angle Stall Speed Increase (%)
0 deg. 49 knots 0%
35 deg. 53 knots 8%
45 deg. 59 knots 20%
60 deg. 71 knots 43%
75 deg. 97 knots 97%

It aggravates me that this kind of information is always used without the caveat...."this is only applicable if you are maintaining altitude...i.e., loading G's...and increasing AOA in the process"....although they do sneak in "because of loading." Ok, what does that mean?

I hate the term "stall speed." Speed at what weight? What load-factor? Are you balanced so that the stall speed is the same on both sides?

This table is better:


Bank angle Stall AoA AoA increase(%)
0 deg. 15 deg. 0
35 deg. 15 deg. 0
45 deg. 15 deg. 0
60 deg. 15 deg. 0
75 deg. 15 deg. 0

:)

- mark
 
Flying is dangerous. (NTSB) Maybe its best to stay home on the couch?

Folks, the 180 return-to-runway or abbreviated pattern is like any other skill - you need to practice it if you have any hope of executing it correctly. Stalls, spins, VFR into IMC... you should practice these things, or your chances of making it is low.

TODR

Ahhhh,, Thanks TODR. We've been doing the 180 "impossible turn" each and every weekend for many weeks now in the glider world at 200'. Come to find out, it is totally doable with lots of training. I've done a few days worth of practice of the maneuver in the RV in the past, but am looking forward to going back and seeing my progress after lots of good solid training and practice. Declaring the altitude and knowing for absolutely certain that that specific altitude with today's conditions is, and has proven to be, perfectly successful is almost liberating. If we could all just stop talking and go out and improve core piloting skills... I'm not ace at all, but we spend our weekends doing these things (today was over two hrs worth of approaches on an IFR flight plan) instead of looking at cows.
 
This table is better:

Bank angle Stall AoA AoA increase(%)
0 deg. 15 deg. 0
35 deg. 15 deg. 0
45 deg. 15 deg. 0
60 deg. 15 deg. 0
75 deg. 15 deg. 0

Maybe...

When the rate of descent is constant, the angle of attack increases with bank. When the angle of attack is constant, the rate of descent is going to increase with bank. Can you add a column that shows the corresponding rate of descent with the increase in bank angle?

Dan
 
I have probably two or three dozen failures in gliders at low altitude (broken wire on winch launches). These have occurred anywhere from 15 feet to 1,500 feet or so, and normally they occur at an airspeed around 5 or 10 knots above stall. Often they have occurred at deck angles of around 45 degrees nose up. Other than the absolute need to react quickly; probably within two seconds, they are no big deal. Similarly, a rope break at 200 feet with an air tow, is no big deal and a turn around to land on the take-off runway is normally easy.

Gliders and RVs are both fixed wing aircraft but there are many differences, notably glide angle. RVs also differ greatly from other fixed wing aircraft like DA-20s and other glider like powered craft. Someone compared RV glide angles to factory airplanes like Cessnas. If I had the choice to do a low altitude turn around in my RV-6 or a Cessna 172, i would sure take the Cessna.

The fact that low altitude turn arounds can be done routinely in low stall-speed, high aspect-ratio aircraft, and that I have done them many times, will not influence me at all to try that stunt in my RV, which has a poor glide ratio, particularly at low speed, and a sink rate that increases greatly with constant airspeed bank angle.
 
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The fact that low altitude turn arounds can be done routinely in low stall-speed, high aspect-ratio aircraft, and that I have done them many times, will not influence me at all to try that stunt in my RV, which has a poor glide ratio, particularly at low speed, and a sink rate that increases greatly with constant airspeed bank angle.

I'm glad you brought that up...........because there is too many comparisons to gliders or lightly loaded wings being compared. Once again, I've seen a lot of spin ins with quarter scale R/C. Lightly loaded wings can make nice easy turns with a lot less altitude loss. With the heavy models, it either a high sink rate, or just figure that it will spin in, if you keep forcing it around........as it usually does. BTW --- I live next to an airport. There has been three unsuccesful 180 turn backs since I've lived here.

L.Adamson
 
For all the glider guys here talking about 200 foot rope breaks, Larry hit the nail on the head - RV's are COMPLETELY different animals, and you might think about the bit that you're setting in some low-time RV pilot's mind. Someone who doesn't have a lot of hours could be reading this thread and going "Hmmmm....there are lots of folks whose name I recognize that think this is doable...so maybe I can do it too...." Is that the impression you want to leave?

Let's face it - folks successfully turn back and land after an engine failure, but many die trying. I would bet that almost every one of those that died trying though they could do it.

"Absolute Altitude" determined by testing? Hey, that's great experience to go an get for your airplane. Now....how does it change with wind conditions? Altitude? Aircraft loading? Do you have a chart that you can use before each takeoff to determine if today's limit is 400', 500', or 600' ? There are a lot of variables - have you considered them all?

I've said this before, but if you turn back, and fly perfectly, you might make it and live. If you DON'T make it, you almost certainly will die. If you land/crash straight ahead, under control at the lowest possible airspeed, you may be hurt, but evidence shows you will most likely live.

Like Larry and many others, I have been trained and practice this in sailplanes. I won't do it in a powered airplane, and I won't tell others that they should even consider it. A hundred years of aviation experience says the odds are against you.

Paul
 
One thing to mention in this thread. This is not to advocate a turn back but something each pilot should explore in his aircraft. Go out and practice accelerated stalls. You would be surprised at how many pilots have never done one. You will learn a lot about how your aircraft if you run through a series of them. Try them at 1.5, 2 and 3 and 4 G's. You may find your particular aircraft stalls quite differently in a accelerated mode with different warning signs then in a 1 G stall. It will also give you a baseline of how much G is available at various airspeeds.

George
 
For all the glider guys here talking about 200 foot rope breaks, Larry hit the nail on the head - RV's are COMPLETELY different animals, and you might think about the bit that you're setting in some low-time RV pilot's mind. Someone who doesn't have a lot of hours could be reading this thread and going "Hmmmm....there are lots of folks whose name I recognize that think this is doable...so maybe I can do it too...." Is that the impression you want to leave?

Let's face it - folks successfully turn back and land after an engine failure, but many die trying. I would bet that almost every one of those that died trying though they could do it.

"Absolute Altitude" determined by testing? Hey, that's great experience to go an get for your airplane. Now....how does it change with wind conditions? Altitude? Aircraft loading? Do you have a chart that you can use before each takeoff to determine if today's limit is 400', 500', or 600' ? There are a lot of variables - have you considered them all?

I've said this before, but if you turn back, and fly perfectly, you might make it and live. If you DON'T make it, you almost certainly will die. If you land/crash straight ahead, under control at the lowest possible airspeed, you may be hurt, but evidence shows you will most likely live.

Like Larry and many others, I have been trained and practice this in sailplanes. I won't do it in a powered airplane, and I won't tell others that they should even consider it. A hundred years of aviation experience says the odds are against you.

Paul

+1000

Doug Rozendaal
F1 EVO
 
And Btw... many gliders are up elevator limited and wont stall above 30 degrees of bank.... There is very little transfer between turning back in a glider vs airplane...

Doug Rozendaal
Private Pilot Glider
 
Yep

And Btw... many gliders are up elevator limited and wont stall above 30 degrees of bank.... There is very little transfer between turning back in a glider vs airplane...

Doug Rozendaal
Private Pilot Glider

Paul and Doug give great advice!

When I trained in a Schweizer 232 (sp?), and was taught rope-break turnbacks from 250' I went :eek::eek: really!!?...horse of a totally different color than a powered airplane.

Best,
 
RV's are COMPLETELY different animals, and you might think about the bit that you're setting in some low-time RV pilot's mind. Someone who doesn't have a lot of hours could be reading this thread and going "Hmmmm....there are lots of folks whose name I recognize that think this is doable...so maybe I can do it too...." Is that the impression you want to leave?Paul

-1000

I think the people reading this FORUM are smart enough to make their own decisions and don't need motherhood...


-Just fly the airplane...if at some point during the turn back it appears you will not make it, roll level and fly it in. You are no worse off than taking the hardline of NEVER allowing the possibility of a turn back. Many airports these days are surrounded by residential areas with little kids playing in the streets or back yard... Why do you get to risk their lives for fear of learning to fly the plane back to a safe haven? At my airpark, one runway has totally open fields for several miles and probably would be as easy as landing on the runway..no brainer. The other runway however, has a huge kiddie park, a ballpark and soccer fields all surrounded by rows and rows of residential homes and a shopping center. No way I'm going straight in from that runway if I have any altitude at all to attempt a turn (600ft). At less than 600 ft I'll start a turn anyway toward the least popluated area (to the right) with expectations of rolling level early and maybe plopping into the little pond before the park.

Making an absolute statement for or against a turn back is in my opinion irresponsible when the manuever itself is well within the capabilities of any airplane provided the pilot learns how to do it.
 
-Just fly the airplane...if at some point during the turn back it appears you will not make it, roll level and fly it in. You are no worse off than taking the hardline of NEVER allowing the possibility of a turn back.

Actually if you have to terminate the turn you are worse off. You are now committed to landing down wind (unless the wind is totally calm).
If the wind is very strong, you may have just changed a mostly guaranteed survivable forced landing into a much less survivable one. The choice to turn back may have been a fatal one even if you don't spin in.
 
Actually if you have to terminate the turn you are worse off. You are now committed to landing down wind (unless the wind is totally calm).
If the wind is very strong, you may have just changed a mostly guaranteed survivable forced landing into a much less survivable one. The choice to turn back may have been a fatal one even if you don't spin in.

it isn't a binary decision.
 
...if at some point during the turn back it appears you will not make it, roll level and fly it in.

The trap here is that you'll be in a tight turn - probably with a high bank angle (remember the overbanking tendency). If you just crank in aileron to recover, you could generate enough adverse yaw to put you into an unrecoverable spin.

Dan
 
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I did my first tests today. I decided on a road that would be used to start the procedure. My energy state was 120 MPH indicated, 700' AGL and 800 FPM climb.

Up to altitude and do several tests pulling the mixture to cutoff...engine stops running then idle mixture in again. It works as it should. Prop never stops.

Climb up to 5000-6000' AGL and set up the target airspeed and climb rate. At the road, mixture to cutoff. I started pushing the nose down too quickly since I wanted to wait a few seconds. Thirty degree bank. IAS always above 100 MPH indicated and when over the runway I had lost 1200'.

Second try I bank 45 degrees. Airspeed still too high and again around 1200' lost.

I am not pleased with the airspeed control. Plus if I am higher, I am also further from the airport so will have to make adjustments the next time I try it.
 
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altitudE loss

I think these experiments are showing a falacy that every young pilot has. That is there is a lot of altitudE loss in the turn. Gliders have long wings ( low span loading) so do not lose nearly as much altitude. But an RV with short wings is going to be losing a lot of altitude just turning around. If one is nervous About laanding straight ahead I would think a box departure would be best.
(Sorry for any errors sent via crappy blackberry)
 
I am not pleased with the airspeed control.
Ron - Good on you for doing the testing.

You aren't happy with the airspeed control when you were all prepared to do the test, you were at a nice safe altitude, you knew the engine would restart as soon as you pushed the mixture forward and you knew there was no personal risk. Think about what the airspeed control would probably be like if the engine failure caught you by surprise, you were close to the ground and knew you had only one shot to pull this off, and if you screwed up you might die.
 
Kevin, my poor airspeed control was not letting it get a bit lower. That should have reduced the altitude loss.

I was well away from a stall/spin situation (whether due to "fear" or safe pilotage is subject to debate).

Another factor is that on a typical departure I have turned crosswind before this point. So really I would be looking at a 180 to the crosswind runway.....possibly a 90 degree to a north-south road. There are plenty of open fields.

I just do not see now how I could get the height down to circa 600' or less as others suggest.
 
Kevin, my poor airspeed control was not letting it get a bit lower. That should have reduced the altitude loss.

I was well away from a stall/spin situation (whether due to "fear" or safe pilotage is subject to debate).

Another factor is that on a typical departure I have turned crosswind before this point. So really I would be looking at a 180 to the crosswind runway.....possibly a 90 degree to a north-south road. There are plenty of open fields.

I just do not see now how I could get the height down to circa 600' or less as others suggest.
The data I have seen from many others seems to be with the engine running at idle, which covers the dreaded "throttle cable breaks and engine suddenly goes to idle" failure case.

The drag with the engine off and a windmilling prop is quite different from what you have if the engine is still running, and the descent rate will be higher. Your testing is much more realisitic from a performance point of view, but it is hard to simulate the "startle factor" you'd have in a real engine failure. Your piloting performance would likely be quite a bit worse in a real engine failure, and that would have an effect on the altitude loss in the turn (assuming you successfully avoided the stall/spin scenario, which is actually quite a big assumption based on actual accidents).
 
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One thing to remember is that "RV" means a lot of different things. The -8 is going to be challenged to do this maneuver in the same amount of altitude than the -12 can.

Wing loading is very different amongst the different models. The -12 is the low wing loading champ at 10.4 lb/sf at MGTW. This is a lot lower than my CT, which is 13lb/sf at MGTW. -8 is probably highest around 16lb/sf. So wing loading isn't so much the issue.

It's probably more about aspect ratio. RVs (except the -12) have fairly short wings that produce more drag than a long, high aspect wing that you'd find in a Diamond or sailplane. The -12 is a little shorter span than many other LSAs, but not hugely so.

As far as airspeed, do you have a "floor" approach speed that you use as a hard floor, i.e., no going below it?

I maintain that the most important thing is to know the limits of you and your airplane and obey them.

TODR
 
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Similar test in a different AC

I did the same "impossible turn" excercise in a Cirrus SR22 and came up with performance numbers for that airframe. Same set up (road for runway, at altitude, etc), airspeed numbers a little lower (90 KIAS - which is very near best glide and typical for that state of a TO) and a 45 degree bank (had to work up to that). Half flaps because that is the POH take off configuration. One key finding was the return to the airport turn needs to be into the wind to lessen the distance you got away from the centerline of the runway (this turns out to have a big effect actually). You really have to nail airspeed control and keep the turn tight, not a lot of margin from an accelerated stall. Lower speed was also important, since speed increases the radius of the turn - letting the plane speed up hurt a lot. Did lots of them to get to this level.

I was able on only one occasion to make 600 feet work (since I never was able to repeat it I consider that an anomoly). I got with practice to be pretty regularly able to make 700 feet work. In real life I would want some margin beyond my demonstrated 700 feet to even remotely consider trying it.

Thanks for doing this test, perhaps my findings can help. My RV is not flying yet, but when it is I will repeat the test in it.

I did my first tests today. I decided on a road that would be used to start the procedure. My energy state was 120 MPH indicated, 700' AGL and 800 FPM climb.

Up to altitude and do several tests pulling the mixture to cutoff...engine stops running then idle mixture in again. It works as it should. Prop never stops.

Climb up to 5000-6000' AGL and set up the target airspeed and climb rate. At the road, mixture to cutoff. I started pushing the nose down too quickly since I wanted to wait a few seconds. Thirty degree bank. IAS always above 100 MPH indicated and when over the runway I had lost 1200'.

Second try I bank 45 degrees. Airspeed still too high and again around 1200' lost.

I am not pleased with the airspeed control. Plus if I am higher, I am also further from the airport so will have to make adjustments the next time I try it.
 
Interesting post Roger.

Kevin is quite correct, you must know the numbers and how you will react if it goes quiet.

The difference is Kevin, from making good pilotage straight ahead, or slightly left or right, or all the way around to a road or taxiway or another runway.......you still have to fly there. If you are scared witless because you have not trained for this, you are going to underperform anyway.

I have said this several times before, know your aeroplane, my -10 will do what a -6 will never do. Know your aeroplane. Know your available options.

Practise carefully .....plenty written already.

A good pilot is never surprised when an engine fails after take off, he is surprised when it does not.
 
One key finding was the return to the airport turn needs to be into the wind to lessen the distance you got away from the centerline of the runway (this turns out to have a big effect actually).
It's a huge advantage to turn into the wind. Obvious, but you're unlikely to do it unless you practice.

The one thing that amazed me - and made me change my flying habits - is that I used to climb to about 500ft at Vx. When I tried the 180 return doing this, I was so high that I barely had enough runway to land on, even slipping like crazy. Climbing out at Vy, I'm able to return to the runway much easier. So now, I climb at Vx only to about 100ft and accelerate to Vy. Now, this is for a very slick airframe like the CT, probably different for RVs.

TODR
 
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