Unreported light aircraft accident

[punkalouver]

Originally Posted by 421dog

“And even if he ended up out of non-IMC options with low fuel over an airport with an overcast layer combined with a cloud base that was not too low, he could have put his aerobatic plane in a spin and held it there until clear of the clouds, then recovered.”

Per the report, Exeter was 500 BKN, 6 km.
Per this aircraft’s POH, it loses 400ft/turn in a perfectly executed spin when loaded to Aerobatic specifications (it wasn’t)

Tell us how that works for you.

Maybe there was a better option…

The better option was finding out good weather airports from ATC and their distance from present position and then getting a vector toward it. That alone would likely have safely resolved the situation this pilot found himself in(at a high altitude above the clouds with low ceilings and vis).

I used the term IF for the spin scenario in my previous post......If a pilot with a likely inability to fly instruments safely were to discover they were over a good weather airport with a fairly high cloud base(say 1500 overcast and good vis), one could spin down through the cloud if they were low on fuel. Would take discipline to do it properly though. That is how it works for me.

[421dog]

So somebody with a thousand hrs that can’t keep the greasy side down through a couple of thousand feet of stratus clouds with the aid of a functional artificial horizon as well as all of the standard VFR instrumentation present in his aerobatic aircraft is going to be able to avoid disorientation in a spin in IMC sufficiently that he can miraculously recover not only his bearings, but also from a fully developed inside spin (not a “Cessna spiral dive”) that requires an active and correct control input, perfectly when he just happens to pop out in the clear.

Ok

[punkalouver]

Originally Posted by 421dog

So somebody with a thousand hrs that can’t keep the greasy side down through a couple of thousand feet of stratus clouds with the aid of a functional artificial horizon as well as all of the standard VFR instrumentation present in his aerobatic aircraft is going to be able to avoid disorientation in a spin in IMC sufficiently that he can miraculously recover not only his bearings, but also from a fully developed inside spin (not a “Cessna spiral dive”) that requires an active and correct control input, perfectly when he just happens to pop out in the clear.

Ok

Choose your risk.

Most pilots with a CAP 10 know how to do a spin very well. They usually didn’t buy it for gaining any instrument experience. Got some news for you. Active input for a spin(called holding it on the stops) ain’t that difficult.

One should keep in mind is that there are plenty of very good aerobatic pilots with no instrument experience who have done thousands of spins and can actually keep the greasy side up better than you ever could(when appropriate).

So yeah, it is quite possible with some pilots. Just do another spin like you did a hundred time previous in your CAP 10 and recover just like you did a hundred times previously.

Hmmmm. 421Dog is USA based. Scared of spins are we, after never having been trained how to do one?

OMG OMG

[megan]

Forget all that. Think outside the box. I take you have a licence, so go try it for yourself!!!.

Didn't work in any I flew, Auster, Chipmunk, Tiger Moth, Victa, T-34, T-28, single Cessnas. Legendary Northwest Airlines Captain Paul Soderlind wrote,

Case Study A

The airplane involved was a four-engine turboprop in airline cargo service.The only occupants were the captain, co-pilot, flight engineer, and a dead heading pilot in the jump seat. The captain and flight engineer were highly experienced and both had many hours in type. The co-pilot was relatively inexperienced but had received all required training and was certified and fully qualified.

The flight was cruising at 22,000 feet at night, between layers, in smooth air. The co-pilot was doing the flying, navigating, communicating — everything— and the flight engineer was attending to normal duties at his panel. (The captain’s activities are relevant to what happened, and will be discussed shortly.) To appreciate what happened to the flight during the next 30 seconds,look at this plot of data from the flight data recorder (FDR) and cockpit voice recorder (CVR):



Times of significant events (in seconds) are read against the horizontal scale at the bottom. The triangular symbols mark the time of relevant CVR comments and other key events. The FDR’s heading trace was inoperative.

The flight was entirely normal up to Time 08 (i.e., eight seconds into the plot above), and had been on autopilot in "altitude hold" mode for over 30 minutes. There were some earlier comments on the CVR about a problem with the co-pilot’s attitude indicator, but after switching its source to the captain’s vertical gyro, operation was normal. Here’s a transcript of the final 22 seconds of the CVR:

08.0 First departure from cruise altitude
13.4 "Altitude" — deviation from normal first noticed Unidentified voice, CAM?
16.0 "What’s happening here" Co-pilot’s voice, CAM2
17.6 Increasing wind noise (airspeed increasing)
17.9 "You got it?" Co-pilot’s voice, CAM2
21.0 "No" Captain’s voice, CAM1
24.0 Landing gear warning sounds begin -power levers pulled to IDLE
25.9 Overspeed warning sound begins
28.2 Sounds of structural breakup
29.8 "We’re dead" Unidentified voice, CAM?

NOTE: In the CVR transcript at left, "CAM" denotes cockpit area microphone. "CAM1" is on the left side of the cockpit, while "CAM2" is on the right side. "CAM?" denotes that the location from which a sound came was unidentified.

The first anomaly begin at Time 08 when the flight first departed from the altitude it had held for over 30 minutes, probably when the autopilot was disconnected. This wasn’t discovered for some six seconds as noted by the CAM?statement "Altitude" at Time 13.4. 1.9 seconds after the co-pilot said"What’s happening here?" he asks "You got it?" — presumably asking the captain if he had taken control of the aircraft. The captain’s"No" was without any particular inflection or concern in his voice.

The descent from Time 18 (Point A on the diagram) to Time 30 (Point B)averaged over 32,000 feet per minute, which is consistent with TDS characteristics.

Most shocking was that it took only 14 seconds to go from normal flight to structural breakup, in good weather and smooth air, with an experienced crew and no evidence of mechanical failure.

The fact that the co-pilot was the sole pilot flying/navigating/communicating was related to the captain’s probable activity during an extended period preceding the initial departure from cruise altitude. Specifically, other pilots this captain had flown with reported that he had a long-standing habit of reading what was euphemistically termed "non-operational material"while flying. Indeed, one could hear pages turning on the CVR recording.

The primary cause of this accident was "nobody watching the store,"a factor that has preceded every TDS incident on which relevant data is available. Complicating matters was a relatively inexperienced co-pilot getting no help from either the captain or the flight engineer.

Case Study B

Another classic incident occurred in the earliest years of U.S. airline jet operations. A four-engine airliner — on a moonless night in smooth air over the ocean — got into TDS, diving from 36,000 feet to 6,000 feet before recovering.Recovery load factor exceeded 6g, and despite a wing spar that was permanently bent, the crew managed to land the aircraft successfully. This near-catastrophe started while the captain was in the passenger cabin, the co-pilot was doing paperwork, and the flight engineer and navigator were working behind an anti-glare curtain between themselves and the pilot stations. The captain (in the passenger cabin) was the first to realize something was amiss. The loss of control began shortly after the autopilot disconnected unexpectedly.

Another no-one-watching-the-store case.

After a detailed inspection by the manufacturer’s engineers, the airplane was declared structurally safe, and it went on to fly out the rest of its years without serious incident.

Aerodynamic and Control Aspects of TDS

The basic problem is an airplane’s spiral mode, which is inherent in the airplane’s shape. Virtually all airplanes have weak spiral stability and "want"to start turning, however slowly. The typical airplane, if left unattended, will simply not go straight for long. To believe that it will implies that it has heading stability — i.e., once headed west, it will keep heading west. But it won’t. There’s no such thing as inherent heading stability.

Assume for the moment that:

1. the airplane is perfectly shaped
   
2. it is perfectly rigged
   
3. it is perfectly trimmed for straight-and-level cruise
   
4. fuel is perfectly balanced between left and right wings
   
5. if multi-engined, power is perfectly balanced between left and right sides
   
6. there is not a hint of the slightest wind shear
   
7. the air is smoother than a mouse’s tummy
   

You will never find such perfection in the real world, but let’s pretend it’s all true for purposes of the discussion that follows.

With a perfect airplane in perfect conditions and nobody attending to the controls, one could conceivably continue straight and level for several minutes,but more likely the time is measured in seconds. In any case, sooner or later a wing will drop — it may be either left or right, the direction being entirely random. When the wing drops, the nose will go down and the airspeed will increase — just a little if the bank angle is small. But with one wing down,the airplane will start to turn. The higher wing being on the outside of the turn is moving faster than the lower wing, producing more lift, causing bank angle to increase, the nose to drop further, airspeed increase even more … and on and on, the situation feeding on itself … a "vicious spiral" in more ways that one.

Once the turn starts, one of two things will happen if the turn is not stopped.

Case 1. The Stable Spiral

When a wing drops, the airplane will begin to turn, the nose will go down and the airspeed will increase. After a relatively short time, airspeed will stop increasing and remain a few knots above the original trim speed, and bank angle will remain constant at 20 to 30 or so. The spiral has reached a stable mode and the airplane will continue in a descending turn as long as altitude remains.

Case 2. The Unstable Spiral

Once the turn starts, airspeed and bank angle will continue to increase, a stable state will never be reached, and the spiral ultimately will develop into a near-vertical dive at airspeed and bank angle far beyond all normal limits. Our "perfect" airplane — perfectly rigged, trimmed, etc. — will usually go "all the way" no matter which wing drops initially. (No two airplanes, even if they are of exactly the same type, will react exactly the same.)

Now so far, we’ve been discussing a "perfect" airplane flying in"perfect" conditions. Neither of these ever occur in the real world,where secondary effects make things worse.

Consider the airplane with only a "bendable" rudder tab adjusted to counter "torque" in cruise. (Never mind that the turning tendency that pilots often refer to as "torque" is not torque at all … that’s a discussion for another time.) Though the tab has been adjusted to offset the left-turning tendency attributable to "torque," it will do so only for one particular combination of altitude, power, indicated airspeed, etc. With any other condition, the tab’s anti-turning force will no longer balance the"torque" and a turn will start. The same is true with cockpit-adjustable rudder trim. Anything that unbalances the airplane — a tiny fuel or power imbalance, for example — will require the trim to be readjusted.Such a small imbalance almost always will go unnoticed by the crew until the airplane reacts by starting to turn, at which point the trim is readjusted.

But what if it’s not readjusted? Will the airplane enter a stable spiral or an unstable spiral? Let’s take another look.

When our airplane is cruising serenely along in smooth air, two opposing turning forces are at work — "torque" tending to turn the airplane left, and the rudder tab tending to turn it right. What happens then depends on which of the opposing turning forces is dominant. If, for example, power increases (a temperature decrease can cause that) and if nothing else is changed, the increased torque becomes dominant and the airplane wants to turn left. But if power is reduced, the effect of rudder trim becomes dominant and the airplane wants to turn right. If the right wing drops first, the increased airspeed strengthens the right-turning effect of the tab and the airplane goes "all the way." If the left wing drops first, the tab’s right-turning forces will dominate when speed increases, and the airplane will reach the stable mode.

Every airplane has a built-in turning tendency — even brand new ones —usually due to miss rig or miss trim in roll or yaw or both. The initial turning tendency is usually small, usually difficult to detect at first, and extremely difficult to isolate the specific underlying cause. The onset is usually insidious, beginning very slowly, usually with little or no seat-of-the-pants clues strong enough to alert an inattentive pilot that something’s awry. An airplane cannot suddenly "snap" into a spiral unless it’s grossly out-of-trim in the yaw or roll axis. Nevertheless, a well-developed spiral often develops with astonishing rapidity, as we saw in our first case study where it took only 14 seconds for a large transport aircraft to go from controlled flight to structural breakup.

The only true "cure" for TDS is avoidance, avoidance, avoidance.Someone must be watching continuously what’s going on, and be prepared to initiate recovery from an incipient spiral without delay.

Recovering from TDS

One widely published recovery procedure involves seven steps, several of which are either unnecessary or can actually be detrimental. Considering the time-critical circumstances under which it might be needed, a seven-step procedure is far too complicated. There is a better one, and it involves only a single step:

Level the wings with slow, gentle rudder pressure, keeping hands off the controls.

Applying rudder produces yaw, which produces roll, and the airplane will unbank. Relax rudder pressure as the wings approach level, then continue to hold them level with the rudder only. Keep hands off the yoke or stick. Do not fret that aileron and rudder are not coordinated in the recovery — coordination is unnecessary.

As the wings begin to unbank, the nose will come up. There is no need to apply back pressure to recover from the dive. The nose will come up by itself with no great increase in load factor (i.e., g force). If the airplane was intrim at a reasonable airspeed before the spiral began, it will return to the same airspeed by itself … provided the pilot doesn’t interfere by applying pitch inputs!

When the nose comes up, it will momentarily overshoot the original attitude,then pitch down again. This pitch-up-pitch-down cycle will continue, the pitch excursions decreasing with each cycle (engineers call this a "phugoid oscillation") until the airspeed settles down at or within a few knots of the original trim speed. (This assumes, of course, that the airplane was trimmed to a reasonable airspeed before the spiral began, and that the C.G. is within established limits.)

The airplane will "take care of itself" in pitch. It"wants" to seek and hold the airspeed (actually, angle of attack) that it had been trimmed to. Its natural speed-keeping stability will return it to that speed. Let it do so on its own.

Every pilot should get an appropriate demonstration from a knowledgeable instructor that:

1. the airplane will begin a turn if allowed to fly hands-off
   
2. the bank angle and airspeed will increase once the turn starts
   
3. the rudder-only, hands-off-the-yoke procedure will work admirably to recover
   

A Caution to Pilots and Instructors

For a realistic, conservative and safe demonstration, allow the airplane only to begin a spiral dive. Don’t let the bank angle increase beyond 25to 30 and don’t let the airspeed get anywhere near redline. Begin at least5,000 feet above the terrain, since the demonstration will take you both below and above the initial altitude. Do the demonstration in smooth air — other wise any gustiness or shear may hide the true effects of the spiral mode. If a spiral dive is allowed to get too steep — meaning with excessive airspeed — the recovery pitch oscillations would be quite large at first, and in the first pitch-up the airspeed may drop to near the stall. Not to worry, the airplane will not stall, though you might get a temporary beep or two from the stall warning system. Excessive airspeed must be avoided, and the demonstration can be accomplished effectively without getting to a high airspeed.

As with all simulated emergency procedures, caution is the word.

Summary

• An airplane left on its own will sooner or later begin to turn, and airspeed and bank angle will increase. All other factors being reasonably normal, a spiral cannot develop to a dangerous degree suddenly, but it can do so more rapidly than many pilots might imagine … in a matter of seconds.
  
• Avoidance is the best medicine. A dangerous spiral cannot develop if someone is continuously "watching the store." This is the only guaranteed method of TDS avoidance. Do not depend on an "unsupervised" autopilot, since it may disconnect unexpectedly, and the disconnection may go unnoticed until a dangerous spiral has developed.
  
• If a spiral develops, use the single-step recovery procedure: Level the wings with slow, gentle rudder pressure, and keep hands off the controls.

[RichardJones]

Posted by me under a different alias. Got banned, didn't I.

Question for ab initio instructors.

[421dog]

Originally Posted by punkalouver

Choose your risk.

Most pilots with a CAP 10 know how to do a spin very well. They usually didn’t buy it for gaining any instrument experience. Got some news for you. Active input for a spin(called holding it on the stops) ain’t that difficult.

One should keep in mind is that there are plenty of very good aerobatic pilots with no instrument experience who have done thousands of spins and can actually keep the greasy side up better than you ever could(when appropriate).

So yeah, it is quite possible with some pilots. Just do another spin like you did a hundred time previous in your CAP 10 and recover just like you did a hundred times previously.

Hmmmm. 421Dog is USA based. Scared of spins are we, after never having been trained how to do one?

OMG OMG

Lots of aerobatic time in everything from aerobats to extras. Been spinning since primary training in the ‘80’s.

Feel no need to be insulting, but I feel that your (IMHO, very irresponsible) suggestion of how to get through a cloud deck in an emergency might be taken to heart by someone who is stuck, and it will most likely get them killed.

I wasn’t talking about active input to get or keep an aircraft in a spin, I was talking about the fact that an aircraft that will truly spin and is in a fully developed spin, will keep doing so even if no control inputs are made until an active input is made to make it fly again. In the Cap 10 (which really spins) in question, it will recover with stick in pro or anti (slower spin , anti spin, slower recovery, faster spin, faster recovery, greater rate of descent pro spin) turn, but will lose less altitude with the stick neutral. It won’t stop spinning without rudder input to stop the rotation, and appropriate nose down attitude (according to the POH)

[RichardJones]

While we are on the subject of spinning. If in a glider and severe turbulence, wave for eg, is encountered., spinning may be the only way out, unless you want to pull the wings off. Spin. All 3 axises are in motion and a/s remains constant, as we all are aware.

[sycamore]

Just a refresh for those of us `over here`,- TDS..?

[treadigraph]

Originally Posted by sycamore

Just a refresh for those of us `over here`,- TDS..?

The Death Spiral (I assume).

[421dog]

Originally Posted by sycamore

Just a refresh for those of us `over here`,- TDS..?

with respect to treadigraph (who is certainly correct and in no way holding myself out as any sort of an engineer), an equally apt (and possibly serendipitous, relative to this discussion) answer might be “Time Delay Systems”. (Just helped my kid through his second semester of Diffeq, and delayed differential equations were pretty much the most complex stuff I ever did in school, so the little sh!ts on his own now). Would be a good introduction though, as to why things that are supposed to be inherently stable sometimes aren’t.

[421dog]

Just out of curiosity (because I never have) Has anyone here ever actually spun an airplane with his eyes closed, under the hood, or in imc? [not in a sim]?

Was right seat in a P-35 Bonanza in 1986 when the PF stalled it (with a flipover yoke on a dark night above an overcast at 18k ft) and, while the PF started to pull (and the airspeed wrapped around 40 KIAS > zero) I reached over, pulled the power and dropped the gear from my non-control position.

All I was worried about was not having the tail fall off,(and, as it happened, it didn’t even screw up the gear doors)

[megan]

Just out of curiosity (because I never have) Has anyone here ever actually spun an airplane with his eyes closed, under the hood, or in imc

Yes, Chipmunk under the hood on limited panel, recovered from the spin ok but everything following was a balls up, had only an hour or two of instrument time at the time.

Just a refresh for those of us `over here`,- TDS..?

The Death Spiral as posted by treaders.

[rob_ginger]

Not a pilot, but an electrical engineer with an interest in aviation: I'm really interested to know how stable various aircraft types are in the roll and yaw axis. I can understand an aerobatic trainer like the CAP10 would be designed with low stability so it can be thrown around. But what about a high-wing Cessna, or for that matter a big transport aircraft like the 747 or A380? From some of the quotes above (e.g. Paul Sodelind) the pilot only has seconds to respond to a slight wing drop before a steeper and steeper turn develops. I'm surprised that any big passenger aircraft could even get certified if it was so unstable that it wouldn't fly hands off for a while (say, more than 30 seconds or so), and even return itself to level flight??

[punkalouver]

Originally Posted by 421dog

I feel that your (IMHO, very irresponsible) suggestion of how to get through a cloud deck in an emergency might be taken to heart by someone who is stuck, and it will most likely get them killed.

Actually, it might save lives in the future. Exactly what is your recommendation for someone that makes a mistake in an aircraft with no instruments capable of supporting IFR flight that is stuck above a layer that has a good clearance above the ground? Try to keep the greasy side down during a 5 minute descent through the soup?

Clouds - Plane & Pilot Magazine (planeandpilotmag.com)

"It’s easy to get stuck on top when your airplane fuel supply is limited. I’m so paranoid about it that I tend to err on the conservative side. A few years ago, a good friend of mine had a scary occurrence. Dr. D., as I’ll call him, was cruising home to an airport outside of St. Louis from a competition in his aerobatic monoplane. He was at 10,000 feet MSL on top of a broken layer knowing he could get down through a hole at anytime, until it became overcast. The radio reported better weather ahead, so he felt pretty confident he could get down closer to home and he kept flying north. Much to his dismay, he reached his destination and the weather didn’t improve—he was stuck on top of an overcast with no way to get down and not enough fuel to turn around. Dr. D., who’s braver than I think I would be, had only two options—to bail out and parachute to the ground or to spin down through the overcast. Recalling maneuvers used by old Air Mail pilots, he stalled the airplane and started spinning through the clouds. He told me later he was sure he would break out fairly quickly, but the altimeter kept unwinding as he got lower and lower. After what seemed like the most unsettling eternity, he finally broke through the overcast at 1,500 feet above the ground. Quickly recovering from the spin, he found his airport, landed, then headed home for a stiff drink. I don’t want to have to do that, but at least I know it’s possible."

[OvertHawk]

Originally Posted by punkalouver

Exactly what is your recommendation for someone that makes a mistake in an aircraft with no instruments capable of supporting IFR flight that is stuck above a layer
"

Don't be there.

If you've got an aircraft without instruments or are not trained and competent to use them then plan properly and don't get stuck. It's like the perpetual chicken and egg arguments we see about IIMC avoidance versus recovery.

The best way to recover from these situations is not to get into them in the first place.

The idea that spinning down through a cloud layer should be advocated as a mainstream method of recovery for anyone other than aerobatic experts is just bonkers. And even for aerobatic experts it demonstrates significantly poor decision making to have got there in the first place. ( evidenced by the pilot in the link above pressing on over cloud becoming dependent on fining a hole).

The accident that this thread began about was tragic for all involved.

OH

[punkalouver]

Originally Posted by OvertHawk

Don't be there.

If you've got an aircraft without instruments or are not trained and competent to use them then plan properly and don't get stuck. It's like the perpetual chicken and egg arguments we see about IIMC avoidance versus recovery.

The best way to recover from these situations is not to get into them in the first place.

The idea that spinning down through a cloud layer should be advocated as a mainstream method of recovery for anyone other than aerobatic experts is just bonkers. And even for aerobatic experts it demonstrates significantly poor decision making to have got there in the first place. (evidenced by the pilot in the link above pressing on over cloud becoming dependent on fining a hole).

The don't go there mindset as a solution doesn't help someone who is in that position(as given by an actual example that I posted earlier). The reality is also that significantly poor decision making is a common fact of general aviation life. In fact, we are on an accident thread with just such an example in which the spin option was a possible outcome if the pilot had decided to not test his instrument expertise(which was marginal in its likelihood to ever work)

The spin recovery idea is a rare scenario involving a double failure but what is someone going to do if they have an instrument failure issue while flying VFR on top(which is legal in many countries) and the weather is worse than forecast? What about a fuel leak scenario. Wish they hadn't got there and that's it? They could consider the situation(aircraft type, known ceiling, spin experience, instrument capability for self and aircraft). The stars may align on rare occasion. It is not a mainstream solution, just a desperation - Out of Other Options scenario to consider.

As for restricting my rare case scenario to aerobatic experts only, the same might be applied to attempting instrument flight, an action that has literally killed thousands over the years with a full working panel of instruments. Not sure I would do it in a Bonanza but what if you are in a CAP 10.

The Don't Be There mindset is a great mindset, but is based on wishful thinking instead of reality for the general population. The same mindset was applicable to Do Not Fly VFR into IMC if not trained to do so. But thousands died trying anyways, so it was decided that the Don't Be There theory was not sufficient and mandatory instrument training became a requirement in many countries for VFR only pilot licenses because it was known that this would continue to happen. My recommendation just one more idea to have in mind that could work in certain rare cases.

[RichardJones]

Originally Posted by punkalouver

The don't go there mindset as a solution doesn't help someone who is in that position(as given by an actual example that I posted earlier). The reality is also that significantly poor decision making is a common fact of general aviation life. In fact, we are on an accident thread with just such an example in which the spin option was a possible outcome if the pilot had decided to not test his instrument expertise(which was marginal in its likelihood to ever work)

The spin recovery idea is a rare scenario involving a double failure but what is someone going to do if they have an instrument failure issue while flying VFR on top(which is legal in many countries) and the weather is worse than forecast? What about a fuel leak scenario. Wish they hadn't got there and that's it? They could consider the situation(aircraft type, known ceiling, spin experience, instrument capability for self and aircraft). The stars may align on rare occasion. it is not a mainstream solution, just a desperation - Out of Othe Options scenario to consider.

As for restricting my rare case scenario to aerobatic experts only, the same might be applied to attempting instrument flight, an action that has literally killed thousands over the years with a full working panel of instruments. Not sure I would do it in a Bonanza but what if you are in a CAP 10.

The Don't Be There mindset is a great mindset, but is based on wishful thinking instead of reality for the general population. The same mindset was applicable to not flying VFR into IMC if not trained to do so. But thousands died trying anyways, so it was decided that the Don't Be There theory was not sufficient and mandatory instrument training became a requirement in many countries for VFR only pilot licenses because it was known that this would continue to happen. My recommendation just one more idea to have in mind that could work in certain rare cases.

A good post. Getting caught out on top can happen to anyone. Geography depending, the chances vary of course. Why do we make make mistakes? Because we are human!! Humans screw up from time to time, this is all part of the continuous learning process. In many types of operation man is becoming the weak link. Most auto pilots and or computers can do mundane tasks far better than any human, for example. It's the interface between humans and computers, that can cause problems. I am very wary of people who "dont make mistakes", When it does happen the mistake can be very big.
Stability. Yes of course some aircraft are far more stable than others. The more manuverable the aircraft the less stable. Some aircraft are so unstable it takes a computer too control the damned things.
Swept wing aircraft were mentioned previously. The wings are swept for lateral stability. However Dutch Roll becomes an issue if the yaw damper quits. The book says it must be rectified/recovered with aileron/spoilers. Hard work. However if you know what you are doing, Dutch roll can be recovered with yaw inputs (as the yaw damper does) at the right time, by the right amount. However I digress.
"Aviation is a highly devolped science. Don't pioneer."

[172_driver]

Not a pilot, but an electrical engineer with an interest in aviation: I'm really interested to know how stable various aircraft types are in the roll and yaw axis. I can understand an aerobatic trainer like the CAP10 would be designed with low stability so it can be thrown around. But what about a high-wing Cessna, or for that matter a big transport aircraft like the 747 or A380? From some of the quotes above (e.g. Paul Sodelind) the pilot only has seconds to respond to a slight wing drop before a steeper and steeper turn develops. I'm surprised that any big passenger aircraft could even get certified if it was so unstable that it wouldn't fly hands off for a while (say, more than 30 seconds or so), and even return itself to level flight??

In yaw - very stable. Like a dart arrow.

In roll - somewhere around neutral, with a slight tendency to go towards wings level. In the mean time the pitch will change and call for action.

[WideScreen]

Originally Posted by RichardJones

..... However Dutch Roll becomes an issue if the yaw damper quits. The book says it must be rectified/recovered with aileron/spoilers. However if you know what you are doing, Dutch roll can be recovered with yaw inputs (as the yaw damper does) at the right time, by the right amount......

Yes, I agree with you on this. Dutch Roll is something completely different as generally assumed. And, once you know that, you know how to correct it.

Now back to your highly disputed recipe: Despite the comments over here and given you seem to have an understanding of mechanical physics, I certainly can understand, a spam-can might become "stable" again when the rudder control is returned to the natural elements/aerodynamics. Though please explain what happens and why. All spam-cans I flew/fly are so unstable, that only a couple of seconds hands-off the yoke, will give a spiral dive. Though, I never tried this without rudder input........

Oh, personally, I might do another trick, when with a C172: Full flaps and dive to the ground, with a > 45 degrees pitch down angle. The speed will be limited to just above 90 kts, "keep wings somewhat level" and your descent is done in minimal time, so the upset chances are minimal, and IF happening your speed will still be far away from TDS/destruction. And, unless there is a very low cloud base, one has sufficient altitude to recover from your controlled dive.

[421dog]

So I have taught both of my teenage kids to keep a variety of aircraft upright in a stable descent in actual as well as simulated IMC using, at a minimum a turn and bank indicator. It was a non-issue even with them in the right seat.
I taught my 16 y/o son to stall, spin and recover a beech sport. He was really good at recovering from the stall (Sports break unreliably and enter an actual spin, not a spiral dive, if active recovery isn’t initiated). He was able to get out of the spin with coaching, but it took him a couple of turns.

i like the odds on learning how to keep the greasy side down with basic instrumentation.

I learned to use the instrumentation present in any aircraft when I became qualified to fly it. It ain’t rocket science.

Clearly, the right answer is to stay out of situations which you are not equipped to be in, but as an out, the least heroic route is likely the safest.