Safety Discussion #1: Stall/Spin at Low Altitude

N355DW said:

Learning aerobatics will make you a better stick and rudder pilot than you are, even if you are a good stick and rudder pilot already. There is no ego in that statement. It's plain and simple truth, you will have a better feel for your aircraft under all flight regimes if you have training and experience flying in all fight regimes.

Aerobatics as a sport or hobby does attract a more risk taking type of personality, however. Don't let that fact influence your opinion about aerobatics as good training. I was not one of those types, it scared the cr*p out me at first, but I knew learning aerobatics would make me a better, safer pilot, so I stuck with it. Aerobatics done down low is what kills most people who die flying aerobatics. There is very little room for error, either pilot or malfunction type.

I also hold an ATP, and that training has also made me a better safer, pilot, in a different way.

More training in any endeavor is usually a good thing. You don't have to take a full blown aerobatics course to get better at avoiding stall/spin accidents, a simple stall/spin course of 2 or 3 hours could be invaluable in this. Once you develop a better "feel" for your aircraft as it nears critical angle of attack in various flight regimes, you will be a better, safer pilot.

There is no ego about this, I am well aware my airplane could care less about my ego, it can kill me just as easily no matter how good I think I am. So I try to stay well trained, and not get complacent.

Click to expand...

No argument with you at all on the benefits of this type training but don't tell me ego does not play a role in GA accidents sometimes involving aerobatics.

Not all young pilots can afford aerobatic training nor is it required by the FAA so I will go back to a previous post and state again, safe flight can be achieved by developing an awareness of air speed to simply avoid the fatal stall/spin turning final. Some pilots manage air speed control and awareness of it very well, have no aerobatic training whatever, and fly an entire life time without incident.

Flying safe does not have to be a big expensive deal but it does require a knowledge of elements that can kill you and lousy air speed control is one of them.

This business is inherently risky and managing it is quite a challenge. I think about it and the age factor everyday. Riding a bike and flying are somewhat similar and would you believe I've quit riding a bike because any fall is serious but flying is still on the agenda. Does that make sense?

It does for the moment. But I wonder why, is it ego? I hope not, I genuinely love flight but for sure the box is getting smaller. Risk management, the perspective changes with time.

David-aviator said:

This thread has jumped the track to a useless expression of pilot ego.

Click to expand...

And we should expect something more?

There is plenty of commentary about training on this thread, be it quantity or quality. Surely, more and better training can help anyone improve. However, the gents that crashed had a combined 40,000 hrs in the air. I imagine some of that included training. Sadly, it did not help them.

Should we expect to be any different? I think it is high on the hubris scale to think we are (or would be with similar training/experience) better than the accident pilots.

It brings another point to consider. How much training (as a % of flying hrs) will we accept? If one trained 1/2 the time, then the effective cost of the utility hrs (trips etc) would double. In the extreme, if one trained 100% of the time, then utility time is zero and you might as well not fly at all. So lets say it is a "low" percentage like 10%, how many of us will howl when the FAA says we must do it? The industry is complaining right now about the recently imposed 1500 hr experience hurdle. While it is different than this thread, the beurocratic goal is the same. Better pilots in the seat.

For me personally, it has been too long since my last training adventure (IFR ticket). I am itching for something new (like acro). Thats good, but in the same vein, I have no interest in getting to the level of repeating training that the airline guys do. The GA accident rate is not high enough to peg my risk meter.

You are correct I hope the merits of additional training and study are self evident.

The purpose of this safety discussion, and future discussions, is to provide flight and training techniques as well as answer questions to enhance pilot safety within the scope of the safety topic. If you aren't contributing directly to that the end, you are only a few mouse clicks away from starting your very own off topic debate thread. As it is now, this one contains perhaps 5 pages of useful techniques with another 5 pages of personal debate which serves only as a distraction in an otherwise useful thread.

Please stay within the focus of this safety topic.

Chris Hill said:

Please stay within the focus of this safety topic.

Click to expand...

You seem very concerned about focus when your original post was fairly lacking in focus. This thread is labeled as a safety discussion, you talk about very pat flight physics that every student pilot learns, then write:

Chris Hill said:

I hope some instructors will talk about distractions in the cockpit, whether instructing or flying with friends, and how to reduce/prevent those distractions, especially during critical phases of flight such as takeoff/landing.

Click to expand...

...Which was addressed in only one post (#5). Ask passengers to stop talking.

So regarding the accident mentioned in the OP, it's not clear who was flying. Since the owner was in the back, I might assume that he was allowing his 93 hr (in RV-8) buddy to do some flying. Since most RV-8's don't have rear seat rudder pedals, I assume the front seater was flying. But that's an assumption.

Another thing that strikes me is their hours. Front seater had 19K total hours, and 94 in the RV-8. I'm really not trying to stir the pot, but people seem to worship high time like this, when the reality is that most pilots with this much time have obtained it mostly by sitting in a cockpit managing their FMS, not doing hands-on maneuvering throughout the entire performance envelope of the airplane. And the 100 hr mark seems to be about the time when pilots start feeling like they really have a "feel" for a particular airplane.

So if we want to have an honest safety discussion, let's start with hubris. 20,000 hrs in transport aircraft? Check that at the door of a light aircraft you have very low time in. No assumption that this was a factor here, but it's a legitimate topic, and it is real.

And regarding flight physics and bank angle vs. stalls speeds (which applies to level turns only), let's not make safety a mental math exercise every time you think about a low, slow turn. You mention distraction. I feel mental distraction is much more common and dangerous than verbal distraction. How about don't be distracted from the feel, weight, and position of the stick? If you pay attention to that very carefully, that will tell you everything you need to know about flight physics and AoA (bank angle is irrelevant), assuming you have obtained enough time in type to learn it...and fly more conservatively until you have learned this. If you feel better putting an AoA indicator in, and focusing on that, great.

This truly is not that complex of an issue. As with flying in general, it's knowing your limitations, developing skill, paying attention, and using good judgment. Yep, that's nothing new. But I'm not sure we've learned a whole lot new in this thread either. Here, we have a pilot who simply screwed up. Maybe because he wasn't paying attention, maybe he was overconfident and had too little skill for area of the envelope he was in at that altitude. Except for mechanical or medical issues, there aren't many more possibilities. And the back seater may have simply been along for the ride. Something to think about when you're flying in an airplane without dual controls.

Couple of quick points:

Training is good, but what most of us need is practice in the training we have already received. Plenty among us only do stalls every two years. Practicing stalls on your next flight doesn't cost anything but gas.

Flying a set profile is a worthy endeavor, but if that is your only defense against the unknown, you are simply relying on luck. There is no guarantee that Mother Nature, ATC, or your fellow pilots will always allow you to fly that textbook pattern. Remember, the skills we had on our checkride is the minimum standard... We should all improve from there.

The discussion concerning the ratings and hours is odd. But to say that an ATP with X0,000 hours is somehow more proficient at basic stick and rudder skills than the rest of us is missing the point. Of the 10 hours that a 757 ATP logs on each flight, how much of that is spent hand flying (stick and ruddering) the airplane? I'll bet its measured in minutes - if there is any hand flying at all. That's not to take anything away from ATP's, but for the purpose of this thread, I'd no sooner turn a 747 captain loose in my airplane than my non pilot wife. That's not ego talking, that's just being practical. I have a buddy who flies KC-135's and only recently "discovered" little airplanes. He told me not too long ago that the few hours in his Swift taught him more about flying than the Air Force had in the last 20 years.

Toobuilder said:

The discussion concerning the ratings and hours is odd.

Click to expand...

Why? Because the points being made (and that you almost repeat verbatim) about transport hours vs. stick and rudder skills are blatantly obvious? Well I agree, but hearing some people express astonishment that 20,000 hr transport pilots with a few minutes per flight of hands on time at bank angles +/-20 degrees could find themselves ill-equipped for loss of control issues at the edges of the flight envelope in a light airplane (RV or otherwise) that they have little time in is beyond me.

Another speculation

I just got around to reading the NTSB report. I noticed a couple of things that may not have been thoroughly discussed.

The airplane in question had full flight controls for the rear seat (except throttle) and the front seat pilot had been reported to be giving flight instruction to the rear seat pilot.

The toxicology report said the rear seat pilot had Ambien/zolpidem in his system.

It is interesting to read the Wikipedia article about Ambien. The following is a quotation:

"Some users have reported unexplained sleepwalking[14][original research?] while using zolpidem, as well as sleep driving, binge eating while asleep, and performing other daily tasks while sleeping. Research by Australia's National Prescribing Service found these events occur mostly after the first dose taken, or within a few days of starting therapy.[15] Rare reports of sexual parasomnia episodes related to zolpidem intake have also been reported.[16] Sleepwalkers can sometimes perform these tasks as normally as they might if they were awake. They can sometimes carry on complex conversations and respond appropriately to questions or statements, so much so that observers may believe them to be awake."

My experience with Ambien relates to my Rv project. Right after I picked up my tail kit I had to go out of town for a couple of days. When I got back my garage door and corner wall was bashed in - over $5,000 in damages, but fortunately missing the boxes with my kit. It turns my neighbor had been using Ambien and had suffered a "sleep driving" episode one night where he went to the store, made purchases, returned home, bashed into my garage, parked his truck, and then gone to bed. The next morning he said he had no memory of any of it.

So one other possible factor for the accident in question is side effects of Ambien.

The rear seat pilot was getting instruction, something that has been encouraged in this thread. If he was at the controls at the time of the accident, his altertness may have been impared, affecting his time to react to the situation. From the front, it may have been difficult to recognize what was happening in back until it was too late.

Perhaps one should be careful of fitness and medical condition, not just training.

Low Altitude Stalls

Lost in the discussion - most very applicable to a safety debate -is the fact that all the numbers regarding stall speed vs bank angle apply only to level flight. Dropping the nose buys additional margin at any bank angle / g loading.

Anytime in the pattern that I have to pull the nose up, I try to recheck the airspeed. Not foolproof - but a good habit pattern.

luddite42 said:

Why?....hearing some people express astonishment that 20,000 hr transport pilots with a few minutes per flight of hands on time at bank angles +/-20 degrees could find themselves ill-equipped for loss of control issues at the edges of the flight envelope in a light airplane (RV or otherwise) that they have little time in is beyond me.

Click to expand...

That's what I find odd. That pointing out this fact ruffles some feathers and generates an "ego" comment or two. I'd just like to stick to facts and experience relevant to the discussion at hand, which is basic stick and rudder skills, not managing a 650,000 pound airliner in class A airspace.

flight dynamics

pvalovich said:

Lost in the discussion - most very applicable to a safety debate -is the fact that all the numbers regarding stall speed vs bank angle apply only to level flight. Dropping the nose buys additional margin at any bank angle / g loading.

Click to expand...

This statement is FALSE! It was also made by Luddite42 and I was about to reply to that when I found this one.

The relationship between bank angle, g's, and stall speed is true for any STEADY flight condition, which includes climbs and descents, as long as the climb rate or descent rate is CONSTANT.

You get extra margin during transients where there is vertical acceleration. When you initiate a descending turn, lowering the nose as you bank and turn, you get extra margin because for a period of time, your descent rate is increasing. At a certain point, you will decide that the descent rate you have is what you want, and you will pull harder to maintain the bank and arrest the increasing descent rate. At that moment, the 'numbers' apply again, and boom! you are vulnerable to an accelerated stall. As Luddite42 said, you can feel this in the stick pressure, and it will tell you all you need to know.

Thank you Steve. I too was formulating a reply.
If you have a g meter and it reads 1g you will stall at the (weight adjusted) stall speed. If it reads 2g you will stall at 1.414 times the 1g stall speed. It does not matter if the nose is level or pointed down.

Technical correction: in a steady state descent the g meter will read slightly less than 1g since the component of gravity perpendicular to the wing is slightly reduced, so stall speed is slightly reduced. But even for, say a 12 degree descent angle, this is a 1% effect - less than one knot.

Right, loading is loading, whether the wing is holding the airplane up 100%, turning the airplane 100%, or a split between the two... There's still only 100% to spread around.

But what dropping the nose gives you is a decreased radius of turn for the same loading. After all, the radius of a turn drops to zero if the aircraft is vertical.

True: But the mis-conception is that a steady rate of descent is all that is needed. As Steve pointed out you must allow the aircraft to accelerate vertically, e.g., rate of descent constantly increasing, in order to decrease the turn radius at the same wing loading.

effects of the g-vector

This is a worthwhile side issue to discuss briefly, because I think there are fairly widespread misconceptions.

In Shaw's book, "Fighter Combat - tactics and maneuvering" he describes how military pilots use the contribution of the gravity vector in either aiding or resisting your turns, and whether the resulting turn radius is decreased or increased.

In addition to the focus here on stall-spin from base to final, another place where the vertical energy exchange can have a big effect is on "the impossible turn" back to the runway after engine failure that clearly is not impossible, just dangerous for the unpracticed.
Any time you are turning and you can use vertical acceleration to help the turn, you reduce the demands on the wing to do the turning. As Toolbuilder pointed out, if you point the airplane vertically at the ground, a turn is now just a roll to a heading.

But you do eventually have to pull out of the dive. So you are exchanging loading demands for turning for later loading demands for pulling out. Someone that does not 'feel' the loading they are asking for from the airplane may try to turn and pull out at the same time, in the latter half of an overshoot turn to final, or in the latter portion of a gliding turn back to the runway. When you ask the wing to do both at once, you should be very aware of your stall margins.

Another area where this is relevant occurs to me -- recovering from spiral dives. Same story exactly. I think many a training syllabus (syllabi?) teach to recover by first rolling the wings level, then pulling the nose up to level. This avoids the combined loading described above.

Just a side note of caution on that recovery method, not important for RV's because they roll quickly. In sailplanes, especially an open-class sailplane with a full load of water, the roll rate is very slow, and if you try to follow this method, then by the time you get the wings rolled level, you will have allowed the glider to reach very high speeds. You could easily over-g on pull-up, and if you don't you may exceed flutter speed. Choose your poison. So, the proper recovery strategy for a sailplane with a lot of roll inertia is that you better start pulling out while you are still rolling. It is also good to use the wing dihedral to help roll, by slipping a bit.

BobTurner said:

True: But the mis-conception is that a steady rate of descent is all that is needed. As Steve pointed out you must allow the aircraft to accelerate vertically, e.g., rate of descent constantly increasing, in order to decrease the turn radius at the same wing loading.

Click to expand...

Yes, you can fly level or have a minimum turn radius, but you can't have both at the same time. It's a little like the contact patch of the front tire of a street motorcycle - you can have maximum braking or maximum cornering, but there is a finite amount of traction to go around.

In any case, if you're at the limit on one, you better hope you don't need the other.

scsmith said:

....But you do eventually have to pull out of the dive. So you are exchanging loading demands for turning for later loading demands for pulling out...

Click to expand...

Thank for bringing up that point. Unloading the wing in the turn (exchange altitude for tighter turn) is a "rob Peter to pay Paul" scenario. That higher descent rate will have to be arrested at some point, and the longer or tighter you turn, the bigger the debt you repay at the other end.