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Mithras

I Broke My A2A 172 :)

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My first proper failure, fantastic.... full throttle up from Cape Canaveral airbase to view some freeware scenery for NASAs VAB. Almost straight away oil pressure light came on, I flinched, looked at the dial for zero oil pressure. Panicked ... The engine cut out ... I knew my drill, I'd run through some lessons on FSX and watched You-Tube videos on emergency descents and landings, I trimmed for best glide speed, dropped some flaps, did 180 and dropped back onto the runway with the stall horn squealing in my ear.

 

Brilliant! ;)

 

What a plane!

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If you are low, you'll never, never turn back to runway. You'll search for a good landing spot in front of you, turning back can stall your plane.

That's the first think I've learned on flight school!

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Oh I was quite high by then, almost 1000', but I see what you mean, that sharp turn will just bleed off airspeed...

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Oh I was quite high by then, almost 1000', but I see what you mean, that sharp turn will just bleed off airspeed...

 Yep, and the plane isn't going to be level when it stalls, so it will most likely be a stall/spin accident, very close to the ground, with no chance of recovery. If you err, the result is violent and ugly. It's called "the impossible turn" but the possibility of making it is sometimes up for interpretation and practice (see video). 

 

That said, when Captain Sullenberger landed in the Hudson, he was 3,000 ft up I think, and it was later demonstrated in a simulator that a 180 degree turn back to La Guardia was actually possible. But commercial airline rules mimic the "impossible turn" rule in GA, and dual engine failures are not to be followed up by u-turns to the airport. Sticking with the hard and fast rules, and picking from the remaining logical options saved passengers that day.

 

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Great to hear your are enjoying the simulation. Its got quiet the life span built into it with some things statistically very very rare to occur (mechanical system failures over pilot error for example). Also with the time modeled sat not being used, even if you stop flying it for a few months and come back to fly the simulation it should prove interesting during the pre-flight and first engine start right away depending on how you left her when last parked up. ^_^

 

Also regarding 'The impossible turn' we have a topic on that at the moment, and its already apparent the differences between gliders and powered aircraft which i thought an interesting thought.

 

Heres the link, unfortunately due to the nature of the video we had to remove it as it was too graphic for our younger forum users;
http://a2asimulations.com/forum/viewtopic.php?f=64&t=40658

 

thanks

Lewis

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Nice video BeachPapa!

Below is another one from real world practice. VERY experienced pilot makes "impossible turn" on 300ft AGL in C152:

 

VIDEO:

ftp://ppaero.pl/Impossible%20turn%20-%20www.ppaero.pl/C152+-+Symulowana+awaria+silnika+po+starcie+z+Babic+-+czesc+2-HD.mp4

 

Theory is that if you make it with 45 degree bank and just above stalling speed your altitude loss will be smallest.

 

But of course if you exceed your bank just few degrees or lose too much speed you will end up in deadly spin.

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Thanks for the link, Lewis! I have often googled aviation phrases or terms (not sim-specific) only to find an A2A thread discussing the matter. You guys have an enormous storehouse of aviation info, and the linked discussion is a good example. Without seeing the video, I can imagine the horror it entails… lucky for us we can practice this from the safety of a computer. 

 

Great video, Twojastara. DL link is much appreciated. That was very well done, and the included GPS track shows just how steep the recovery needs to be. Even despite that roller-coaster pitch angle, the stall horn is going off like Miles Davis. Very scary, and shows just how dangerous this maneuver can be.  Come to think of it, I have no idea what a survivable turn back altitude is for any of my sim planes, I should get practicing…   

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Stalling in a turn does not lead to a spin. You can easily enter a spin from a wings level stall if you are uncoordinated. The stress of making a fast turn back to the runway might be the last straw that makes one skid the turn while also trying to stretch the glide. If you use the rudder and ailerons correctly, you can't spin.

 

This is why you should always brief yourself on what to do if your engine fails just before you take the runway. Know what you are going to do at specific altitudes.

 

Turning back to the runway from 1000 feet high should be somewhat easy unless you have a short field and/or a strong tailwind. 300 feet is crazy! Wow!

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Stalling in a turn does not lead to a spin. You can easily enter a spin from a wings level stall if you are uncoordinated.

 

Thanks for your comment because it made me to read more about this topic and I have learnt something new :P However I disagree with your statement.

 

Coordinated turn will reduce weight imbalance which will eliminate one possible cause for spin. However, you can anyway enter spin even being in coordinated turn, because during it the upper-wing will have little more relative airspeed then the lower wing (because of being in a turn) thus at critical airspeed lower wing will stall before the upper one.

 

Quotuing link below:

The increase in drag yaws the aeroplane toward the down-going wing, which may further delay the stall of the up-going wing as a result of increased airspeed. This process, where yaw causes roll, which causes yaw, is known as autorotation.


 

http://www.caa.govt.nz/fig/advanced-manoeuvres/wing-drop-stalling.html

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Okay I thought about what I said and can agree that stalling while being in a turn, even a coordinated turn, is more likely to result in a spin entry than a wings level stall. However, the technique to recover and prevent a spin remains exactly the same.

 

Being uncoordinated can trigger a stall that goes directly into an incipient spin. Skidding a turn increases the difference between the angles of attack felt by the inside and outside wings exactly as you noted above. Additionally, a descending skidded turn is the worst combination, which is exactly what one might find themselves in during a engine failure and turn back to the runway. So the moral is no stall no spin and keep those feet alive the rudder.

 

For an example of how effective the rudder is at stopping a spin see this video. These are loads of fun to practice.

 

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My first proper failure, fantastic.... full throttle up from Cape Canaveral airbase to view some freeware scenery for NASAs VAB. Almost straight away oil pressure light came on, I flinched, looked at the dial for zero oil pressure. Panicked ... The engine cut out ... I knew my drill, I'd run through some lessons on FSX and watched You-Tube videos on emergency descents and landings, I trimmed for best glide speed, dropped some flaps, did 180 and dropped back onto the runway with the stall horn squealing in my ear.

 

Brilliant! ;)

 

What a plane!

Too cool!  I spent hours upon hours teaching students "ABCDE" when the engine sputters/stops.  It's neat to see someone with no real world training (or so I assume) self learning basic emergency procedures and techniques.

 

Emphasis on the ABC.

 

Airspeed;  Pitch & Trim for best glide.  In most well rigged C172s (all models) trimming all the way to the trim up stop will give you hands off best glide.  Remember how you're trimmed when practicing because the go-around can be a real bear.  Not sure if the trim trick works in the A2A 172, I don't own it.

 

Best field for landing.  Field length, obstacles (houses, power lines, ditches), with plowed rows, no danger to people on ground, etc.  Use slips before flaps and don't come up short or long!

 

Checklist.  Now that we're flying the airplane (Aviate, Navigate, Communicate) we can worry about the checklist if there's time.  Memory items (in bold) and then to the checklist.

 

Declare your emergency if you have time and need to.  Use common sense.  DON'T shout on unicom or tower as I've had students try to do.  Make a position report and state your emergency if you think you should.  Maybe transmit on 121.5 as well.

 

ELT.  Manually activate the ELT if you believe you're going to bend it up pretty bad.  If I'm unconscious I want to be found.

 

I've had several engine failures.  All but one was a partial power loss.  That prompted me to train partial power losses to my students.  I would pull the throttle off to 1300-1600 RPM and say "you lost a jug!"  Fun times!

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Theory is that if you make it with 45 degree bank and just above stalling speed your altitude loss will be smallest.

This sounds like a recipe for disaster.

 

 

However, you can anyway enter spin even being in coordinated turn, because during it the upper-wing will have little more relative airspeed then the lower wing (because of being in a turn) thus at critical airspeed lower wing will stall before the upper one.

 

The lessons is "To carry out a stall from straight and level flight (and the turn) recovering from a wing drop with minimum altitude loss."

 

The paragraph you quote from in your link is discussing the possibility that flaps were extended at unequal amounts (rigging etc). Quoting your article:

 

The wing that reaches the critical angle first (at about 15 degrees) will stall first, losing lift and causing a roll at the stall. This often happens because of poor pilot technique where the aeroplane is out of balance at the stall, or aileron is being used. (emphasis added)

 

Quotuing link below:

From your link:

 

If the aeroplane is reluctant to drop a wing at the stall, alter the power and flap combination (refer CFI) and relax rudder pressure to simulate the pilot's failure to maintain directional control. Alternatively, a gentle turn may be required (5 degrees angle of bank).

 

There is nothing underhand about these techniques, as permitting the aeroplane to yaw or stall in the turn are possible causes of a wing-drop stall.

 

----------

 

From The Airplane Flying Handbook (FAA-H-8083-3B)

 

An airplane will stall during a coordinated steep turn exactly as it does from straight flight, except that the pitching and rolling actions tend to be more sudden. If the airplane is slipping toward the inside of the turn at the time the stall occurs, it tends to roll rapidly toward the outside of the turn as the nose pitches down because the outside wing stalls before the inside wing. If the airplane is skidding toward the outside of the turn, it will have a tendency to roll to the inside of the turn because the inside wing stalls first. If the coordination of the turn at the time of the stall is accurate, the airplane’s nose will pitch away from the pilot just as it does in a straight flight stall, since both wings stall simultaneously.

 

To enter a spin, you must have *both* a stall and a *sufficient* yaw moment.  A coordinated turn, by definition, has the yaw canceled out.

 

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Thanks for your comment because it made me to read more about this topic and I have learnt something new :P However I disagree with your statement.

 

Coordinated turn will reduce weight imbalance which will eliminate one possible cause for spin. However, you can anyway enter spin even being in coordinated turn, because during it the upper-wing will have little more relative airspeed then the lower wing (because of being in a turn) thus at critical airspeed lower wing will stall before the upper one.

 

Quotuing link below:

http://www.caa.govt.nz/fig/advanced-manoeuvres/wing-drop-stalling.html

 

I think maybe you're misinterpreting some key points.  The only reason a "weight imbalance" (I'm assuming lateral) would cause the spin would be because of correction of over banking tendency. Correcting over banking tendency would of course mean the lower wing would have a higher AoA because of the downward deflected aileron.  More lift, more drag, greater angle of attack on the inside wing.  I'm tying to still wrap my head around what you mean by weight imbalance.

 

Many argue if over banking tendency even exist, so we typically throw that abstract and negligible effect out of teaching.  Maybe I'm missing what you're arguing?  At any rate, if the ball is in the middle, no spin.  Simple as that in GA airplanes.

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Well, OK Guys ^_^

It seems that I had different expectations of what stalling in a coordinated turn looks like. From that quote from Airplane Flying Handbook it seems that it is less violent - no spin until poor pilot technique.

Thanks! I have learnt something new again :lol:

 

What I meant by "weight imbalance" is that there is some lateral force? lateral momentum? I guess I am using wrong term since English is not my first language.

 

This sounds like a recipe for disaster.

 

Yes it is! It takes lots of experience to do that correctly. But I mean that pure theory says that in 45 degree bank and minimum speed you will have the lowest altitude loss in a turn.

 

I am now finishing my PPL and if I would had engine loss at less than 500ft I wouldn't even try to do this turn. Just land ahead...

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Interesting timing for this topic. I just finished the forced landing exercise for my PPL yesterday. I might attempt a 180 deg turn at 500ft in the Samba XL I was flying in as she has a very good glide ratio but not in more traditional trainers like the C172 or Cherokee. Its a tough decision though cuz at some airports you don't have much space at the end of the runway due to residential areas or other obstructions.

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Yes it is! It takes lots of experience to do that correctly. But I mean that pure theory says that in 45 degree bank and minimum speed you will have the lowest altitude loss in a turn.

The "pure theory" part of your post had me scratching my head... then I found a paper I had read by David F. Rogers (United States Naval Academy) The Possible 'Impossible' Turn where this "pure theory" is discussed. He also wrote a paper The Penalities of Non-optimal Turnback Maneuvers.  Both can be found (google for pdf) and I think are worth reading.

 

So yes... there is the theory... and then there is the actual "practice".  For that, here's a good article from Flying Magazine on the practicalities of such a manuever: The Human Factor: Big Push, Improbable Turn

 

What I meant by "weight imbalance" is that there is some lateral force? lateral momentum?

I thought you were referring to "pro-spin" yaw forces... which slips / skid would the two big ones for starting the autorotation.

 

Thanks! I have learnt something new again [ :lol:]

 

 

Thanks, me too... I always do in these discussions.  Part of why find them so valuable.

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Twojastara,

 

Do yourself a favor after you get your PPL and sign up for spin and upset recovery training. You can thank me later ;p.

 

It is a ton of fun and very mentally and physically challenging. You'll need a strong stomach for 45 minutes of air work but it is worth every second.

 

I also recommend Rich Stowell's book Stall Spin Awareness. I flew with him for that training and I would say the book is very useful prereading. It is very good to understand the physiological impacts of spinning and how they can totally interfere with your cognitive processes.

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Great Ozzie thanks for some reading materials. I will browse those during the weekend.

I have recently found this "pure theory" in Polish equivalent to "Flying" magazine. And I'm pretty sure the author did mention about this paper by David F. Rogers :rolleyes: but I don't remember exactly.

 

Do yourself a favor after you get your PPL and sign up for spin and upset recovery training. You can thank me later ;p.

 

I will! I was discussing this last flight with my FI. I was in intentional spin maybe 3-4 times with my FI - he said it would be good experience to me. And I must say this is scary as s*** :lol: But I didn't recover from those by myself. I want to do training after which I will be confident I can do it.

 

I also recommend Rich Stowell's book Stall Spin Awareness. I flew with him for that training and I would say the book is very useful prereading. It is very good to understand the physiological impacts of spinning and how they can totally interfere with your cognitive processes.

 

I will try to find it. Thanks!

 

I think that the most valuable thing I've learnt from this thread is to change my bad habit of correcting bank first before pushing the stick when I am starting to stall and one wing slowly drops. I had numerous sitiuations like this while flying a2a c172 (in real world I am more cautious of course :P ). And this got me thinking to change this bad habit once for all.

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I also recommend Rich Stowell's book Stall Spin Awareness.


I actually ordered this a couple days ago from Amazon.   :P

 


And I must say this is scary as s***


I will confess, years ago I was nearly petrified of spins (more accurately, large deviations in pitch from level flight).  I was not so comfortable with things like departure stalls...

Then I took an Unusual Attitudes course in a DHC-1 Chipmunk.  After the first couple of spins... I actually started having a blast spinning.  Great Fun!  And a great confidence builder.

Welcome btw for the links.  Very interesting stuff.

-Rob

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Lot’s of interesting points and articles to read mentioned here. I have to ask how many “balls” can be juggled at the same time by a pilot… (trying to keep my puns limited here) Though a perfectly centered ball won’t spin the aircraft, even during stall, who is really looking at the ball while they are stalling at 500ft? I’d be looking at the ground, and trying to judge how close I can get to it before I can’t pull up anymore. Keeping an eye on yaw moment in a post-stall maneuver during an airshow at 2,000ft is a surgical pre-planned maneuver, but 500ft after takeoff is a different scenario.  

 

Also, at 300-500ft after takeoff you might be compensating for crosswind or prop torque with aileron or rudder, and now the engine goes out, your rudder/stick input is immediately out of balance and inappropriate. This needs to be corrected, the ball perfectly centered, and kept there during the entire length of the turn back maneuver (if you chose to spin the roulette wheel) which requires a 45 degree bank-dive to the ground with 270 degrees of required turning radius w/ final correction and flare. 180 degrees only got me to the little league field that lies parallel to the airport during practice in FSX. Which again begs the question of whether to look at the ball or the ground/horizon. It's a pretty scary scenario either way.  

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In order to remain coordinated you don't need to look at the ball. You can feel it in the seat of your pants. Unfortunately you can't get this feedback in the simulator.

 

You have to be in tune with the specific aircraft you are flying as well because each one will feel different.

 

The ball doesn't have to be dead center to prevent a spin. If you stall and start to yaw or drop a wing, the ball isn't going to do anything for you at that point anyway. You need to stop the yaw and recover from the stall. The horizon outside the window is your best tool at that point.

 

The issue with being uncoordinated is that you can induce a stall with yaw with no warning that rolls over very quickly into a spin. Then if you do the wrong thing and try to counter the roll with aileron you have now added every possible pro spin input.

 

If you practice good habits and can maintain coordination without using the ball then you'll be much better off if an emergency occurs because it will be second nature.

 

One also really shouldn't have to think about all this very much. It is drilled into you during training and tested and retested during the check ride and check out.

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Lot’s of interesting points and articles to read mentioned here. I have to ask how many “balls” can be juggled at the same time by a pilot… (trying to keep my puns limited here) Though a perfectly centered ball won’t spin the aircraft, even during stall, who is really looking at the ball while they are stalling at 500ft? I’d be looking at the ground, and trying to judge how close I can get to it before I can’t pull up anymore. Keeping an eye on yaw moment in a post-stall maneuver during an airshow at 2,000ft is a surgical pre-planned maneuver, but 500ft after takeoff is a different scenario.  

 

Also, at 300-500ft after takeoff you might be compensating for crosswind or prop torque with aileron or rudder, and now the engine goes out, your rudder/stick input is immediately out of balance and inappropriate. This needs to be corrected, the ball perfectly centered, and kept there during the entire length of the turn back maneuver (if you chose to spin the roulette wheel) which requires a 45 degree bank-dive to the ground with 270 degrees of required turning radius w/ final correction and flare. 180 degrees only got me to the little league field that lies parallel to the airport during practice in FSX. Which again begs the question of whether to look at the ball or the ground/horizon. It's a pretty scary scenario either way.  

 

 

Instead of staring at the ball during stalls, I will have students look at the wingtip in relation to reference points outside and beyond it.  If the reference point(s) is moving left to right, right rudder (and vice versa).  Of course this is helpful when wings level.

 

VFR pilots should always have "eyes outside".  Some say 80% outside and 20% inside. I demand more time outside with my students. To a point of doing entire lessons with airspeed, DG, and/or altimeter covered.

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The issue with being uncoordinated is that you can induce a stall with yaw with no warning that rolls over very quickly into a spin. Then if you do the wrong thing and try to counter the roll with aileron you have now added every possible pro spin input.

 Which is exactly the why I think a pilot should weigh the risk vs. reward in keeping an aircraft with failed engine close to stall territory. The seat of the pants feeling might be helpful, but it has also proven to be misleading to pilots. We are not organisms built to fly, and our seat of the pants feelings can often be wrong. Zach's technique of looking at the wingtips seems to address this issue better than pure seat of the pants feel. But I'd still question the risk vs. reward of any low altitude maneuvering with loss of an engine.

 

I don't mean to be a wagging-the-finger type, but my interest in aviation has led to read a lot of safety record information and NTSB reports on planes that I am particularly fond of or have novel engineering features. I will never stop being surprised how pilots (even with lots of experience in competent planes) can end up in such bad circumstances. Low altitude spin cases are some of the most cringe-inducing reports to read because they are so preventable, and yet there are so many. 

 

 

Instead of staring at the ball during stalls, I will have students look at the wingtip in relation to reference points outside and beyond it.  If the reference point(s) is moving left to right, right rudder (and vice versa).  Of course this is helpful when wings level.

 

VFR pilots should always have "eyes outside".  Some say 80% outside and 20% inside. I demand more time outside with my students. To a point of doing entire lessons with airspeed, DG, and/or altimeter covered.

 

That’s quite informative, thanks for mentioning this technique. I’ve noticed that wing tips hold a lot of info, and indicate oscillations well. I will try to integrate this technique. 

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We are not organisms built to fly, and our seat of the pants feelings can often be wrong.

 

This is true,m which is why flying in IMC can very quickly prove fatal for someone without training. In VMC, the combination of the visual cues over the nose or out on the wingtips along with the seat of the pants all work together (or should) to give you the information required to retain control. I would not want to be in that same situation in IMC as it will be quite a bit more challenging to execute an "impossible turn".

 

I also like to read the reports in my spare time so that I am always learning from others mistakes, lest they be repeated.

 

A failed engine and low to the ground is no time to bring out your inner Bob Hoover. :rolleyes:

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