Preventing Stall/Spin Accidents

Phantom arrested landing

I’ve touched on this subject before (see Aviation Myth #14), but for some reason the idea that limiting bank angle will prevent stall/spin accidents keeps rearing it’s ugly head.

It doesn’t. It can’t. It won’t.

Angle-of-bank limitations have been suggested by flight instructors, alphabet groups, pundits, and most recently by Richard Collins of all people. In an Air Facts article last month, he wrote:

The pilot of a Mooney stalled and spun in, apparently while making a steep turn to try to patch up an overshoot of the turn to final. This happens and is easily addressed by never exceeding 30 degrees of bank below 2,000 feet. When the decision is made to “bend” an airplane around at low altitude it is likely to be bent, literally. The moment the pilot decides to try to salvage a bad approach is when risk peaks.

I’m sure Collins is well aware that stalls and spins have no relation to bank angle. You can stall an aircraft in level flight. In fact, that’s how most intentional stalls and spins are performed. The only requirement is that the airfoil be made to exceed the critical angle-of-attack. The same is true with spins: they are not related to aircraft attitude whatsoever. It is only necessary that the aircraft be uncoordinated when the wing is stalled.

An arbitrary bank angle limitation does not make a stall/spin scenario less likely. It does the exact opposite, forcing a pilot to skid the aircraft rather than make a steeper (yet properly coordinated) turn when necessary.

And it will be necessary at some point, due in large part to that very same bank limitation. How’s that for a chicken-and-egg scenario? Lower bank angles mean larger radius turns. The larger the radius, the more skill and precision one must exhibit in order to intercept a specified ground track, as a pilot must do prior to landing. It would be like trying to fly the pattern on autopilot. Oh, you could probably do it, but it would be clumsy, difficult, and you’d be limited to one of those gargantuan, bomber-sized patterns which takes you far from the airport at low altitude — unsafe in its own right — while simultaneously annoying folks both on the ground and in the air.

Many pilots don't know the difference between a slip and a skid and lack an appreciation for the distinction.

Many pilots don’t know the difference between a slip and a skid and lack an appreciation for the distinction.

Some of these bank limits would make landing at certain airports nearly impossible. Kern Valley Airport (L05), with it’s tight downwind adjacent to steep terrain, comes to mind. Collins must know this; he’s been aviating almost since the airplane was invented. That’s what makes his stance so mystifying. When we encounter birds or a traffic conflict in the pattern, are we to stick with, say, a 20 degree bank and accept the collision? What about a moderate over- or undershoot on final? I know, “just go around”. But when bank angles are limited, even that may not be enough.

Two years ago, I recounted the story of what happens when these kinds of limits are placed on a student pilot. It’s something that would have fit right in with Collins’ “Risky Moments” article:

I was at an uncontrolled airport one day watching pilots do their thing, when a student pilot entered the pattern and announced her intention to land on runway 25. On her first attempt her Cherokee blew through the final approach course and she wisely went around. The next time she did the same thing. The third attempt was a larger pattern with an earlier turn to final which resulted in an undershoot. Trying to fix that, she allowed her glidepath to get too high. Another go-around.

By this point the student was pretty rattled and, I’m sure, more that a little embarrassed by her inability to land. You could hear it in her voice as she made various radio calls. After four or five attempts someone had to talk her down via the radio.

What the heck had happened, I wondered? Was there an abnormally high wind aloft just pushing her through the final? Was she turned loose by her instructor with insufficient training? Perhaps there was a mechanical problem with the airplane. Was the traffic on the CTAF too distracting? Maybe she was from a quiet country airport (as if we have any of those in Southern California…).

Further investigation revealed that her CFI had taught her not to exceed some arbitrary bank angle in the pattern. I don’t remember if it was 20 degrees or 30. Maybe it was 15. The exact figure is not important. This poor lady’s instructor had told her that the way to avoid an inadvertent spin in the pattern was to limit her bank angle.

Student pilots often demonstrate a lower (though still adequate) level of performance at cross country airfields than at their home airport due to higher workload. Unfamiliar surroundings, dealing with a CTAF instead of a controller (or vice-versa), different runway numbers and pattern altitudes, etc. That’s when mistakes are more likely to be made.

Saddling the student with a hard limit on bank angle is just asking for a stall/spin situation. That’s my real objection. It’s not simply that angle-of-bank limits don’t work. It’s that they create the very situation proponents claim they’ll prevent.

It would be far easier and safer for pilots to simply learn proper coordination and angle-of-attack awareness. Instead, we try to make due with one crutch after another: angle-of-attack computers, stall warning devices, mechanical rudder limiters, elimination of spin training, curtailing full-stall exposure. And now, of course, bank angle limits. It reaches the point where pilots get so wrapped around the axle about how load factors increase with bank angle that they forget this is only true while maintaining a constant altitude. It’s a rote response, the very lowest level of learning.

Sure, highly specialized flight operations might call for high-tech solutions. If you need to stop a 50,000 pound swept-wing fighter on a pitching carrier deck within 340 feet, flying an exacting angle-of-attack is, if you’ll pardon the pun, critical. By all means, use that AOA gauge. But most of us are putting an aircraft weighing 90% less on a runway that’s 1,500% longer. These programmed, mechanical solutions to basic flying scenarios are not an adequate substitute.

Angle-of-attack awareness and proper coordination are “Flying 101″ tasks which are literally taught in the first few lessons of a student pilot’s career. If anyone holding an airman certificate lacks these rudimentary skills, aren’t they acting as pilot-in-command without really knowing how to fly?

17 comments

  1. It’s the dumbing down of the pilot base. Just teach what to do, not why. Everyone can fly right? As far as your example of an autopilot on during a pattern, it is a recommended practice at some training facilities for circling. Works well in a busy environment, single or two pilot crews alike.

    1. Good point about the autopilot, Steven. They can be extremely helpful for maintaining altitude in low weather conditions while keeping an eye on the runway.

      Even in those scenarios, though, I bet the autopilot disconnect would be pressed either before or during the turn to final.

  2. You know, Ron, I used to be in the camp of helping myself with generous bank angles when I flew a Cherokee with 150 hours. But eventually I understood that the reason I needed those turns was that I was speeding by quite a bit. Keeping my speed in check made it much easier to make pattern corners. The sad part was, I learned that 100 hours past my checkride.

    An interesting thing is that up to a certain point, going into steeper turns faster offsets the stall speed raising with loads, with one exception: wind gusts. Should you hit a sink while doing 90 mph you have the margin you don’t have when at 65 mph.

    1. It’s not sad, Pete — we’re continually learning throughout our flying lives. I’ve discovered things at 6,000 hours that some people figured out at 600 hours. That’s just how it is.

      As far as the pattern goes, ideally we should be able to fly at varying speeds to order to maximize efficiency and safety. For example, I often find myself in the pattern with very slow airplanes like Cubs and LSAs. Being able to match their speed can help spacing without extended downwinds that take me far away from the airport. Likewise, speeding up or turning base early for a short approach can get me down ahead of a heavy airliner coming in on the parallel runway. That’s a boon for safety because I avoid wake turbulence concerns.

      Part of this is borne out of the fact that I fly from busy airfields. People in remote places might not even think of these things.

  3. Put me into the camp of those that believe we should be focusing on the real issue here, which is not a limited bank angle for turning base to final, it isn’t knowing the difference between slipping & skidding, etc… The real issue here is WHY did the pilot, or why does any pilot overshoot final? Teaching and encouraging throughout the pilot population proper planning is really the matter at hand. All pilots understanding and having the ability to apply concepts such as with a direct crosswind, use the runway that provides the headwind on base will go a long way and actually address the issue at hand. Similarly, how do we deal with a tailwind component on base, what is the plan for not being able to dissipate the usual amount of altitude on base because a wind is pushing you over the ground faster than you normally travel and as such you are higher when you turn to final? The real focus concept really is pilots having the ability to plan for the variety of conditions we encounter. If pilots planned better then there would be no need for the uncoordinated “bank and yank” fix to the overshoot, because the overshoot wouldn’t happen… Just my two cents, take it for what it’s worth… That being said, I do agree with the author that many pilots don’t know the difference between a slip & skid, which is also a problem.

  4. Bravo Ron! There seems to be a need to not over complicate the stall spin issue, but I think that does more harm than good. In the end a well trained pilot will not have to worry about this scenario. I wish our training curriculums better reflected this need.
    Brent

    1. Right you are! The training curricula you speak of does exist, but it’s up to the pilot to go out and find it. You got that kind of thing at APS, for example. I learned to fly at Sunrise Aviation, where the curriculum is heavy on that sort of stuff.

      The problem is, when one is a primary student, they tend to assume the FAA-mandated training elements will teach them everything they need to be safe. On paper, it looks good: stalls and spins are listed is the PTS. Perhaps the need, then, is for better (and I would suggest, more practical) stall and spin education.

  5. I know that without bank angle limitations in the pattern, students would routinely exceed 60 degrees of bank on that turn to final. The concern is not merely about spins or load factors. Some students need that guideline while figuring out how to fly a safe, normal pattern.

    1. I agree with you, Robert! An excellent point: they absolutely need guidelines for learning how to fly the pattern — and many (most?) other things, too. That’s entirely reasonable.

      It’s also quite different than “never exceed X degrees of bank”, especially because Collins was ostensibly referring to a private pilot (or higher) certificate holder rather than a student.

  6. I once heard an instructor say that a pilot should always lower the nose of the plane in any turn!
    He went on to say that you could never stall the airplane if you followed this simple rule.
    What hog wash

  7. Ron,

    The problem here, as you’ve pointed out, is that people are skidding in turns in the circuit which can result in a spin if the airplane is stalled. I don’t think the fix for the problem of skidding turns is to either limit bank angle or to limit angle of attack—the proper fix is to teach coordination!

    A general bank angle limit of 30 degrees in the circuit is a good idea in my opinion. I don’t mean that you can’t go 31 degrees bank if you see you’re overshooting the final course… sure, go 35 degrees if you need… but realize that you’re right around that 30 degree mark and you shouldn’t bank further. There is no reason to get crazy with bank angle in the circuit. Make students blow through the final course… Who cares?! Fly back (coordinated) and reintercept the final course. The #1 rule in all cases is fly the airplane (in this case, in coordinated flight). This is what needs to be taught at the very beginning. A very solid foundation of flying skills is what prevents this. The problem’s source isn’t in the circuit, the problem’s source is the first few flying lessons.

    Cheers!
    Jordan

    1. Good points, Jordan. The working title for my post was “Keep It Coordinated”, actually. You summed it perfectly by noting that “a solid foundation in flying skills” is the preventative measure, and something that we could use a lot more of. That’s one of the reasons I encourage tailwheel, glider, and aerobatic experience.

  8. Hi Ron! I appologize in advance for shamelessly hijacking the thread, I’d like to report that i just passed the CFI initial ride the other day with las fsdo and i’d like to thank you for the help you provided with technical questions and stuff. Its an exciting feeling along with the sense of the new responsibility!
    I support your stance regarding the stall/spin training, its a shame that the FAA and the industry is choosing to ignore the elephant in the room by minimizing or altogether eliminating the exposure to spins and some stalls, avoiding fully developed stalls, etc.
    People have a fear of the unknown, and fear of not being in control of the situation, and i believe that they are given a huge disservice in the form inadequate flight training when they are not trained to handle the situations such as upset recovery.
    Anyways, thanks for shining the light on these subjects and all the best!

    1. Hey, that’s great! Congratulations on the successful checkride. Glad I was able to help. Those CFI initials are quite a hurdle (as they should be)! You’ll learn more as an instructor than you ever did as a student, so you can look forward to a continuing education… except this will be one in which someone else pays the tab. :)

      Thanks for the support on the stall/spin thing. I believe eventually the tide will turn toward more stick-and-rudder proficiency and emphasis on stall/spin exposure. You can already see it happening due to the Colgan and Air France accidents.

  9. Thanks Ron. You’re exactly right, there is so much more to learn, and im open to it. While i didnt get this rating for the money or the hours, its nice not having to pick up the tab for a change! The idea is to sequence the gig with the primary one (a&p) to minimize burn out and become a career cfi rather than a time building machine.
    Im sure youre well aware one the new “minimum loss of altitude is not the emphasis” notation for stalls in every PTS. Im starting to realize that the FARs (and related docs) are indeed written in blood. Its discouraging to see the FAA and other gov-t entities so bureaucratic and so slow-moving. It’ll be interesting to see how the GA evolves going into the future, the development of technologically advanced aircraft vs basic stick-and-rudder aircraft seems to be continuously diverging.

  10. Arrrrggg!!!! I was in the US for flight training and managed to get my FAA Private, Commercial, Multiengine IFR done, but golly was it painful at times! I have about 1000 hrs. and consider myself a safe pilot and even though I think my instructor was reasonably good, it really irritated me no end being told to limit my turns in the pattern to 20 degrees and “I don’t want to ever see 30!!!!”. It felt horrible having to get used to this “new” technique for flying. Usually, I don’t exceed 30 degrees in my turns around the pattern, but sure, occasionally you want to use a bit more when overshooting or practising precision landings. Having the instructor constantly be yelling at you to do it “right” and skidding around was really off-putting and messed up many landings. Unfortunately I think I realised too late that the instructor was not taking into account my previous flying experience and just started me off at zero.

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