A pilot can fly upside down and not know it?

Factual Questions
21

I remember reading a report of a jet that had a problem that resulted in it going into an unusual attitude and it was recovered “the long way around” so it ended up doing a roll. That maybe what you’re thinking of.

To expand on what others have said about your body getting fooled, you are able to sense accelerations and you can tell roughly what g loading you are under i.e. you know if you feel normal, light, or heavy. Your middle ear can’t sense steady states and it can’t sense very small accelerations. To put this all into perspective, you can sense when you roll into a turn but you can’t tell the difference between being established in a turn and being in straight/level flight.

What will happen is you will be flying straight then the aircraft will gradually roll into a turn. The rate of roll will be below your ability to sense it and you will still feel like you’re flying straight. Then you notice something doesn’t feel quite right, you look at the artificial horizon and notice you are banked, so you roll wings level. Great, except that you roll wings level at a rate your body can sense, so now your internal gyros have told you that you’re flying straight (didn’t perceive the initial roll) and are now telling you that you are rolling into a turn when you are actually rolling back to straight/level flight. At this stage, unless you’re trained in instrument flight, you’re probably going to be stuffed. Your eyes are telling you one thing (if you’re still looking at the A/H) and your body is telling you something completely different. The sensations from your body are much more powerful than the information coming from your eyes and so you do what your body is telling you too.

You roll back to an angle that feels right but now you’re banked in a turn. Because you’re banked the nose drops a bit and you start losing altitude. You notice that you’re descending so you pull back a bit on the controls to stop the descent. If you are banked enough, this will just tighten the turn and before you know it you are in a steep spiral dive.

A study some years ago showed that an average pilot, untrained in instrument flying, has about 3 minutes to live after entering cloud (assuming not enough clear sky below the cloud to recover.)

22

Well, it’s not real glamorous.

You do have to know that where I finished my private license is on the south end of Lake Michigan, where we can and do get “lake effect” weather. I took off to practice my S-turns and other maneuvers in preparation for my upcoming checkride. I had checked the weather and my plans had been OK’d by the flight instructor on duty (my regular instructor wasn’t there at the time, but my early morning excursion had been planned in advance and the CFI on duty was stepping in to keep an eye on me). When I took off visibility was seven miles with a broken cloud layer at 12,000 feet, clearly Visual Flight Rules weather.

So… off I go. I’m merrily doing S-turns and steep turns and stuff like that when I suddenly realize things are getting hazy. Visibility is dropping. So I start off back home. I’m only about 25 miles away, in airplane that cruises at 100 mph so it should only be about 15 minutes to get back home, right? No problem.

Well, it kept getting hazier and hazier and the cloud layer wasn’t broken anymore it was solid and starting to get lower. I knew I shouldn’t be in the clouds so I flew under them. At a certain point I realize I’m only about 600 feet off the ground, no longer sure where I am, and the ground is starting to disappear into whiteness. THAT’s when I realized I was in deep doo-doo.

I had been heading towards a radio tower as a landmark (get above tower. Turn left 90 degrees to a heading of north. That puts you right over the end of runway 09 at my home airport in about 5-6 minutes.) when I noted that I could no longer see it. I made a 180, as I had been instructed to do as a way of getting out of sudden low visibility. The problem was, it was no better behind than before and the clouds were forcing me still lower. I’m four hundred feet above the ground and just about ready for a brown alert in the underwear because I can barely make out the grass - or whatever - below me. I am setting up for a climb and dialing in the Gary ATC when realize I’m going over some sort of farm field. I thought “Hey, I could LAND there!” as I pass over it, basically dragging the field. At the end of it, I do another 180 and bring the airplane down.

Keep in mind, by that time it was so foggy that when the wheels touched down I couldn’t see the other end of my “runway”. I was scared to death some animal or human was going to be out in that field and I wouldn’t see them in time to avoid a dreadful Bad Thing. I honestly don’t know how fast I was going when I touched down, as I was straining to see what was ahead and hoping to god there wouldn’t be any sudden obstacles. The stall horn burped as I touched down, and later I would note I had 40 degrees of flaps down though for the life of me I don’t remember putting them down. Anyhow - it was like driving a pickup truck across a rutted farm field at 70 miles an hour, but far less stable. A rise the middle of the field threw me back up into the air briefly, and by applying full engine power briefly I managed to bring the nose up enough so I landed on the wheels and not the prop. I then yanked it back to idle because I knew there was very little room here.

When forward motion ceased everything that had been in the back of the airplane was now either on top of the panel or under it, mixed up with the right-side rudder pedals. The landing had actually blown the seat cushions off the empty passenger seat. I tried to turn off the engine but it didn’t work the first time, so I managed to find the checklists (that was under the rightside rudder pedals) and figure out what I had neglected to do and got the prop to stop going around (Yeah, just a little shook up!).

I staggered out of the airplane, somewhat surprised my legs would hold me up and gratified I had not actually pissed in my pants. I swore and kicked at the landing gear, checked to make sure the airplane was secure, then headed over to the nearby house.

The gentleman who owned the house had been having his morning cup of coffee out on his back porch when I landed. I don’t know what he had been expecting to get out of that Cessna 150, but it probably wasn’t lil’ ol’ me, pigtails and all. Once we were over our mutual shock I asked to use his phone, which he had no problem with.

I then called the airport and got the receptionist, who was a little surprised that I was calling from somewhere else as I had not mentioned a cross country. I said I had a problem, I was alright, could I please speak with someone in authority? OK, no problem - the flight school director got on the line and I mentioned the sudden change in weather and that I had landed. The director said that was OK, just let him know what airport I had landed at and they’d send someone to pick me up.

I said I wasn’t at an airport.

Absolute silence for about half a minute. Then he said “Oh.”

Then I started babbling that I was OK and the airplane was probably OK and –

He cut me off and asked me where I was.

That’s when I realized I didn’t even know if I was in Illinois or Indiana. Oops. I asked the person who owned the phone, house, and field and then I relayed the address. The director asked if I could, possibly, fly the airplane out of the field when the weather cleared. I said not a chance, explained the lack of distance available, and said it would take a better pilot than me to get the airplane out. Personally, I was concerned they wouldn’t be able to fly it out and would have to take it apart and drive it back on a truck trailer, then reassemble it, but did not mention that at the time. The director said they’d send someone out for me, just stay put.

Like I was going anywhere.

So, anyhow, the Lake County sheriff sends a chopper. By that time, the fog is lifting somewhat although visibility still sucks. Well, yeah, it’s not like any other airplane was going to get in to that field. So out of the chopper steps the airport owner, who also owns the flight school and the airplane which is sitting in the middle of a small field in Illinois. He’s the old guy who’s all dour and intimidating looking and I haven’t really met him before. It occurs to me that this may not be the best first impression. The owner goes over to the airplane, looks it over, still looking all dour and stern and old and grumpy. Then he comes over to me, towering over me, and says in his gruff voice “You OK?”

“Y-y-yeah”

He gives me one of those pats on the shoulder guys give each other, which almost knocks me off my feet and says “Good job on the landing - airplane looks fine. You can fly anything I own anytime. Now get in the chopper and go home.”

So I climbed into the chopper. As we’re about to take off I tell the deputy “No - wait! I want to see how he gets the airplane out of there!”

The deputy looks at me. “Are you nuts? You almost crashed an airplane, and now you want to hang out here 10 feet above the ground and watch that guy do some crazy barnstorming shit to get off the ground?”

“Uh… yeah. I do.”

The chopper pilot laughs, says I’ve the flying bug bad, and says I’ll do alright. So we sit there, 10 feet above the ground, and watch the Old Dude get the airplane out of the field. He took a couple ground runs, probably judging acceleration and ground conditions, then set up for a textbook shortfield landing, goes for it, and when he approaches the fence on the far side, still not quite going fast enough to fly, he pulled back to “jump” over the fence, land on the other side, then finished the take off roll on the far side of the fence.

The airplane followed the chopper back to the airport. Both those guys were instrument rated and knew where they were going, so I didn’t worry about it although I would not have wanted to fly even with the “improved” visibility. A mechanic was waiting, and declared the airplane fit to fly. I then had to go home, TOTALLY freak out my husband, get a shower, get dressed, and go to work.

The next day I was also scheduled to fly, but told to show up an hour and a half early as there were some people who wanted to talk to me. Now, in an emergency a pilot had very broad authority but after the emergency is resolved can be called upon to justify any and all of her actions. Which is exactly what the talking was all about. As I said, not the most comfortable morning I’ve ever had, but not as bad as the day prior. I was cleared of all wrong doing, the FAA and FSDO guys thanked me for not making them fill out the paperwork on a dead pilot (yes, they really did phrase it like that) and praised my handling of the emergency, although they weren’t exactly happy with me getting into the mess in the first place.

Then I went out, preflighted the airplane, and took my scheduled lesson.

As to what the hell happened – when the water of Lake Michigan and the land adjacent to it are of different temperatures, a shift in the wind can cause an air mass above the lake to slide up over the land and generate a hefty fog bank. This is NOT fog rolling in - it’s air rolling in and turning into fog. I didn’t fly into a fog bank, it formed up around me. The wind had shifted from west to north, off Lake Michigan, and set up conditions for instant fog.

Now, in retrospect, if the same thing happened to me again today (which I fervently try to avoid!) I might opt to either climb to around 4000 feet when the visibility started to drop - since lake effect weather usually doesn’t extend much about 3000 and in any case would get me above ground obstacles - and go south, out of the range of the weather effect. But I won’t say for sure, because any bad situation has to be dealt with as it is, which doesn’t always conform to theory. If I can’t get away from the fog bank fast enough I might wind up landing in a field again if that seems the best choice. I also pay a LOT more attention to wind direction (if it’s coming off the big lake I’m very cautious) and keep a much better eye on the distant horizon in all directions.

Definitely one of the more educational flights I’ve made, and the lessons have sunk it, but it was pretty rough at the time.

And, oh yes, two days later my husband bought me my first cell phone and insisted I carry it - cause next time I wind up in a field there may not be a phone I can borrow nearby. My protest that I intended to stay out of fields in the future made no impact, as he pointed out that I hadn’t intended to land in that one, either.

Several months later my CFI took me on a planned flight into actual IMC, where I was able to both keep the airplane upright and navigate at the same time. Having a qualified IFR pilot and CFII sitting next to me did a lot for my stress levels, of course, as I trusted him to keep me from getting us killed. Not that I had any illusions that I was qualified to fly into clouds on my own - I’m not, and I did need help from him to complete the flight, but it was another interesting exercise and MUCH more pleasant than my prior encounter with clouds. I will state, though, that even in the very smooth conditions (the CFI took some pains to make the flight as easy as possible - no rough weather, for example, or low ceilings, or turbulence) and my familiarity with our planned route it was very difficult for me to do this and yes, at times disorienting. Even under “ideal” IFR conditions it was problematic - in any sort of rough weather at all, or after dark, or a combination of the two, I can see how a pilot could easily get into a serious problem if they didn’t stay on top of the situation.

23

Awesome story, Broomstick, and very well told.

24

China Airlines 006 suffered an engine flameout at 41 000 ft ASL which led to asymmetric thrust and resulted in the plane rolling and pitching down. The pilots managed to regain control of the aircraft at 9500 ft. There were two severe injuries and substantial damage to the aircraft. Hereis the NTSB report.

25

Sorry for the double post… I just can’t help myself. The NTSB report states

The plane was a 747SP, a modification of the 747-100.

26

Because I really can’t help myself… that China Airlines plane was repaired and returned to service; this photo is from 2005. So a 747 can do a 360 and the airframe will survive.

27

But still a most instructive tale and well told.

28

Not to carry paying passengers though. That one was only returned into service as a private plane for hippies with a cargo hold full of marijuana to spread around the world.

29

Vestibular researcher here !

As a matter of fact, altough I have never been in a plane (except an airliner), I have quite some experience of what you are talking about, thenks to our fancy NASA-like 3D rotating chair, our centrifuge, and so on…

Well, first of all let me tell you how much I enjoyed this post. Seven years of vestibular research have made me really curious about flying, an in perticular about the motions illusions one experience while flying. One of these days I’ll contact some colleagues at the NASA. I’m sure they could arrange me some funny rides in fancy machines. Meanwhile, I can only enjoy the splendid narrations such as I find in this thread… and all of the rides that I want on my chair.

I have little to add to what pilots here have already said, except maybe a little bit of vestibular physiology. So, basically, we perceive self-motion in space through the vestibular system (so-called ‘equillibrium organ’) in the inner ear.

  • First kind of illusion: we sense gravity though the otolith, which are, in *very *rough approximation, a set of little (damped) pendulums inside of a box (the box = the head in our analogy). Most of the time they do their job at indicating vertical when you tilt the head. However, they will swing around if you shake the box (= running) or they will be deviated if you place the box in a centrifuge. The brain is good at dealing with the running situation (it will correctly interpret the swinging around of the otoliths as a linear acceleration) but will get fooled during the centrifugation. Hence the false perception of vertical when an aircraft turns.

Even non-pilots know how strong is this effect. When one sits in an airplane which is about to land, it frequently makes series of turns, during which one looses the perception of vertical. As a consequence, one will ‘see’ that the horizon is tilted. Given the fact that the brain usually interprets the visual horizon as a reference for horizontal, it really takes a powerfull illusion to create this feeling.

  • Second kind: we sense rotations through the semiricular canals. These are basically circular tubes filled with a liquid (the endolymph). When you rotate the tube, the endolymph tends to remain stationnary in space. The relative displacement between the canal and the endolymph is detected and results in a rotation signal which is sent to the brain.
    Here, the problem is that after a while the endolymph begins rotating together with the canal, and the rotation signal fades away. This is what gives you this delighfull feeling of irreality when you are dancing the waltz with a beautifull partner. But this is also what tricks unexperienced pilots who want to make a turn. As time passes, they will increase their turn in order to maintain their perception. This is called the ‘death spiral’, if I’m correct.
    So far, I guess all pilots knew what I said. Let me add a little bit about the ability of human brain to process motion information:
  • most of our responses to motion (postural adjustments, vestibulo-ocular reflex) are driven by ‘raw’ motion information which come directly from the sensors and work fine in everyday’s life. In contrast, more ‘cognitive’ functions, i.e. tracking your orientation in space require central integration of motion cues in the brainsteam and the cortex. Bad news: we humans suck at this. In perticular, we can keep a central estimate of rotation only up to 20°/s. If we are to perform a barrel roll at 30°/s (i.e. one turn in 12s), we will still manage to track the vertical thanks to our otolith. But above 60°/s even the otolith fail ! Their activation will be interpreted like a linear motion of the head (‘the box being shaken’). During constant roll rotation at, say, 90°/s, humans feel like they are upright all of the time, and oscillating strongly upward-downward and sideward. I suspect that various kind of ‘strong’ maneuvers can saturate the central vestibular system.
    We can generate some pretty fancy kind of sensory stimulations with our chair. Experience shows that these have a strong ‘emotive’ impact, even for us who know in advance what is going to happen (like ‘oh my god this is impossible I can’t be moving like that it feels like aaaaaaaaaaah I’m falliiiiiing’, although we are in fact not moving and we know it). I can imagine how it feels when you have a plane to pilot on the same time !
30

How do they know this was the cause of JFK Jr.'s crash? Do they rule out all other reasons such as plane mechanical problems?

31

They rule out mechanical problems for the aircraft and physiological problems for the pilot. Then they have to come up with a most likely scenario based on the pilot’s experience, the weather conditions at the time and any other information they may have, eye witness accounts, ATC radio recordings, etc.

32

Broomstick, that met the dictionary definition of “a great landing”, didn’t it? As in, not only did you walk away from it but the aircraft was still usable.

Ditto on the “well told”. :applauds:

33

Another few pence.

I recall a flying article/experiment where they took pilots (and they may have even been experienced pilots) up in a plane. They would then block their vision so they could not see outside the plane, like you would get in fog or in a cloud or perhaps at night with cloud cover.

Virtually every pilot, if not every pilot, lost control. Most only took a fraction of minute. Even the good ones only made it a few minutes before spiralling out of control.

If you dont have the right instruments AND training AND skill to use them, flying without visual cues is extremely dangerous.

34

I know someone who participated in NASA research in “the chair”. It was on the KC-135 “Vomit Comet” while flying zero-G arcs. He was told nod his head up and down, eyes closed, while they spun him around. Something to do with studying motion sickness.

He tells me it… “worked”.
:eek:

Question for you: Are you familiar with “somatographic illusion”? When a person focuses on a single point of light, it appears to move around. Supposedly, a pilot doing so could overcontrol the plane and become disoriented.

This is one of those teaching points where I tell the students about it, but have no direct experience. Is this a common phenomenon?

But I’ll again point out that pilots strive to never reach the point of true disorientation. When flying on instruments, the rules of the day are:

  • Keep scanning the instruments. Don’t spend more than 3 seconds or so away from the panel.

  • Make small control inputs so you don’t cause a major perturbation.

  • Ignore your bodily senses because they WILL be wrong.

35

A very typical scenario for a 'graveyard spiral is this:

The airplane is flying along in the clouds, and a wing slowly drops. The pilot does not detect this.

The airplane starts a descending turn, because it loses lift when the wing drops.

The pilot, not trained in instrument flying, doesn’t realize anything is wrong until substantial speed and bank has built up. The pilot finally cues in because of the change of engine pitch, or wind noise, or because the pilot sees the altimeter unwinding.

The pilot pulls back on the stick, thinking he or she is in a dive. This has the effect of simply tightening the spiral.

The velocity picks up rapidly, the altimeter is unwinding like crazy, the pilot is yanking back on the control stick in panic, and the airplane spirals right into the ground.

At a certain point, the plane may be going down so fast that even if the pilot realizes what’s going on, it’s big trouble, because if the pilot manages to roll the wings level, the sudden lifting force will be so great that it will rip the wings off - especially if the pilot is still pulling back on the stick. So you actually have to push forward on the stick as you roll level - a move that is completely counter to every instinct screaming in the pilot’s head.

What makes all this very likely is a phenomenon in the brain which causes us to lose our lateral thinking ability when panicking. Under conditions of stress, our brains go into a sort of flight or fight mode: “Runrunrunrun! PullPullPullPull!” This is why people have burned to death because in a panic mode they couldn’t figure out a simple door latch. In aviation, we try to overcome this through repetitive training, checklists, and conditioning.

Even trained pilots can fall prey to this. I remember one airline accident that was traced back to a faulty autopilot system. The pilots had faith in the autopilot and their own senses, and simply refused to believe the instruments. The cockpit voice recording had them talking about the ‘broken altimeter’ because it was unwinding so fast, and they let the airplane just fly itself right into the ground.

36

If a pilot is not trained in full instrument flying ,they should still know how to look at and read instruments, is that correct?

37

Knowing what to do isn’t the same as trusting the instruments over what your body is telling you.

38

Jaaaa, the so-called vestibular coriolis effect (the name is not really correct since it has little to do with the coriolis force). Mother of all motion sickness stimuli.
What happens is that your canals are sensitive to angular acceleration. An angular acceleration is a change in the angular velocity in a head-fixed frame of reference. You follow me ?
Suppose that you sit on a rotating chair with your head tilted backward. The axis of rotation, relative to your head, is going up and a little forward. Now you tilt your head forward. The axis of rotation is now going backward relative to your head. If you plot a vector along this axis, which length is equal to the angular velocity of the chair, you see that this vector rotates backward (still with me ?) Take the difference between the vector while pitch forward and backward, and you obtain a vector which is parallell to your naso-occipital axis.
That’s a little bit of geometry, but so, the result is that everytime you pitch your head while rotating on the chair, you are activating your canals in a way which tell you that you are turning in roll.
Problem (on earth): you are actually not turning in roll. And your otolith tell you that you are not. So you induce a conflict between canals and otolith. And your brain does not like it. Hence the sickness !
As a matter of fact, there was no otolith signal since he was flying zero G. I guess that this is what the guys wanted to measure… funny that he got sick anyway. Well, people get sick anyway on zero-G planes. No wonder it’s called ‘Vomit comet’.

Btw, I’ve been giving myself these kind of stimuli (on earth). I can tell you, when the chair rotates 150°/s and I pitch 90°, I feel it ! I actually gave myself the illusion that I was tilted 45° in roll. While my otoliths were telling me that I was sitting upright. That rocks !

Uuuuh… somatographic illusion if the fact that you loose the sense of verticality when an aircraft accelerates forward. Am I correct ? I guess that it could lead you to see the point moving, but then it would have to be a really violent acceleration.

It is again this otolith-being-sensitive-to-both-gravity-and-acceleration thing. I generally explain it like this: suppose that you sit on a car. If the car is tilted backward, you will feel an increase of the pressure of the seat on your back. If you accelerate the car forward, you will feel the same kind of pressure. So you could confuse forward acceleration or backward pitch. What happens is that the otolith will get confused the same way, and that your brain will favour the backward pitch perception. That’s because (think to our ancestor cavemen) we have evoved in an environment when backward pitch are common, but high forward accelerations are not.
Then comes the danger. If you believe your senses just after you take-off, then you are going to overestimate the backward pitch of your plane, and so you will try to pitch forward to compensate. Bad.

A common instance of this illusion is when you drive a car uphill or downhill. You tend to involontary slow down as you drive uphill, and accelerate as you go downhill. It is exactly the same effect, just slightly more complex since you are summing up some real acceleration and some real tilt.

39

Ahaaaaa… that would have been in the late 60’s, maybe ?

40

You are - I used the wrong term with my description. I was asking about “autokinesis” (a type of visual illusion), and mistakenly called it somatographic illusion. :smack:

So do you know anything about autokinesis? I’ve never experienced it myself, and I wonder how common it really is.