Every pilot likes to assume a certain immunity from stalls and the confidence is not misplaced. Nonetheless, stalls continue to account for many accidents and in this video—complete with dancing graphics and flapping birds—AVweb’s Paul Bertorelli describes how he blundered into an incipient stall for the simple reason of not paying attention to the business at hand. It wasn’t exactly a near crash, but more of a wake-up call.
Home Multimedia How I Stalled On The Base Turn (And Got Away With It)
Very nice video. Thank you!
I had a too-close encounter with a red tail hawk. He popped into view while I was on final. I pitched up to avoid him, he folded his wings and pointed straight down to avoid me. It didn’t work. He impacted my right wing about a foot inboard of the tip. Scared the crap out of me, and killed him dead. The most disappointing part is the knowing that had we each done nothing to avoid the strike, there would have been no strike.
Thanks Paul. This was a good lesson, well presented.
Just this past Fri. On the hold short at a local Class Delta – “Holding short for landing traffic”. A twin flying a nice stabilized glideslope. Per the ATIS “Birds in vicinity of the airport – all quadrants”. It’s a Red Tail and it’s right over the EMAS at the end of the arrival end of the runway at about 150ft. Right on the glideslope. Looking up from the ground into the clear blue – it’s as plain as day. I’m thinking for the twin looking down onto the textured airport surface it’s not nearly so obvious. Especially as it’s more or less hovering.
Notwithstanding the airport belonging to tower – do I call it?
Check back in post 2 for an answer……
I did NOT call it. I had sufficient time to determine that at this point it might be a distraction the pilot didn’t need and the hawk was moving enough that when the plane got to where it was stooging around – it would no longer be there. Which was the case. And the plane landed normally.
But I’ve been left second guessing myself on that one. If it was my home CTAF field I would have automatically called it.
Was I put off by the frequency belonging to tower? I’m pretty sure not so. I’m not that easily intimidated.
Was I correct to think it might be a distraction to the landing plane? Well so would a bird strike. But it didn’t happen.
Was the subsequent long landing and long roll out because the pilot saw it and adjusted for it anyway? Who knows – he was arriving and I was leaving. Didn’t ask him.
What if’s. But I’m still wondering about that one – even though it turned out OK.
It’s a tricky decision that has to be made quickly with perhaps no 100% correct answer. I had a similar situation last Saturday while pulling in to the runup pad – I noticed a herd of perfectly-camouflaged deer grazing in tall dried hay about 50 yards from the approach end of the runway. Two training aircraft were in the pattern and one was on about a half-mile final. Deer are dumber than a box of rocks and completely unpredictable when spooked, which happens often. From the radio calls, I was pretty sure that the pilot was receiving dual instruction. So I announced “xxx traffic, be advised there’s a herd of deer just east of Runway 28”. I could see the landing aircraft adjust its path from an on-the-numbers touchdown to further down the runway. A learning moment for the student and I received a thank you from both aircraft. Now, if the downwind-base-final CTAF calls had sounded like a solo student’s, the scale would have tilted toward not broadcasting an advisory. Students also tend to be unpredictable when spooked and that risk would outweigh that being posed by a possible collision with deer. Tricky decision for sure.
I’m sorry if I missed it….
At some point don’t we blame the bird for failing to use it’s “radio” and flying a non standard traffic pattern ? Clearly it’s Covids fault for forcing so many young “birds” into the left seat prematurely filling all the needs at the corporate and airlines…
Birds. Meh. They are a fact of life if you fly. Around here every thermal is full of buzzards and those suckers make a hawk seem like a sparrow. Hint: go over not under since they stoop when threatened. Of course pulling on the stick increases AoA so …
As for stalling, I inadvertently stall pretty regularly because I fly and I teach aerobatics. Maximum available turn rate and minimum turn radius at whatever airspeed you are at always occurs right at stall so if you are asking for max performance from the airplane, you are going to be flirting with stall all the time. You get used to the “soft stick” and nibbling at the buffet.
I always wince when I hear someone say, “If you keep the plane coordinated, it won’t spin.” The only way you can keep the airplane coordinated is for the wing, at least the part where the ailerons are, to be unstalled. If the wing is stalled, the ailerons don’t work (or at least they don’t do what you think they are going to do, which is why there is an A in PARE) so there is no way to keep the airplane coordinated in a stall. All you can do is use rudder to prevent rotation around the yaw axis and then get the wing unstalled (reduce AoA) so you have full control of the aircraft again. Welcome to the beginning of UPRT.
Rich Stowell has produced a fantastic program called “Learn to Turn” which addresses all these things. Want to be a better pilot? Go look at https://www.richstowell.com/learn-to-turn/ and then go practice with a competent CFI. (Not all CFIs are created equal. The 300-hour product of a 141 school is NOT likely to be competent to do anything but run a G1000 in a C172.)
The ideal objective for base to final is follow the FAA’s recommendation – keep the pitch below the horizon where it keeps the airplane on the glideslope while using the power to maintain 1.4 x Vso.
A nicely done video, but, as admitted within, more of the same. Not wrong, but there’s a huge misleading assumption contained within: stable air. Another assumption is: wingspan = zero. Glider guiders generally learn pretty quickly, this ain’t so.
Suppose one is gliding along and approaching the dead center of a thermal, what happens? While air is rising vigorously at its center, on the edge, it’s going down! The first sign of it is sink! Not only is the overall air motion down, but it results in a rapid reduction in AOA so the wing is not generating the same lift for a given pitch relative to horizon. Glider pilots are taught to *speed up*. While one goes faster than the best still-air L/D one also gets through the sink more quickly resulting in a lower net loss of altitude. It also prepares one for what comes next.
Wham! Now you’ve hit the rising air. Not only is the mass of air rising, but your AOA has suddenly increased for a given pitch relative to the horizon and the wing generates more lift, increasing drag and slowing the plane down.
What would power pilots do? Hold altitude! (We get yelled at for not doing so). Sink? Pull back to achieve the original AOA, plus that required to avoid loss of altitude in sinking air. Airspeed slows. (Yes, a right thing to do is add power, but how many really jockey the throttle open/closed on a bumpy cumulus day?) Next, Wham! Hitting the core of rising air, AOA increases instantly for a given pitch relative to horizon. At cruise speed, or better, V(a) perhaps it doesn’t really matter. At 1.3 V(so) or below (remember, you just pulled up and slowed down to compensate for the preceding sink) there’s a good chance you just stalled in level flight.
Okay, that’s bad enough. Now let’s assume the more general case where one hits a thermal at a glancing angle. All the above remains generally true, but one wing encounters air rising faster than the other. The difference in AOA causes a roll away from the more-rising air and toward the less-rising air. Compensate with aileron, if you can. Now, just one wing stalls. Spin! No rudder input or misuse required. (In *stable* air one needs that to get one wing to stall before the other, in *unstable* air, not so).
Generally too, similar effects can happen on days where there are large wind gradients present. AOA changes without the pilot doing much of anything, and, particularly in a bank, can affect one wing more than the other.
IMO, anticipating and properly dealing with unstable air when slowed in the pattern and on approach is vastly under-emphasized, probably because it’s rather complicated. A partial exception is training given to airline pilots regarding micro-bursts. And IMO, many stall/spin accidents happen because of these effects. It almost happened to me, recovery to level flight at 50 feet, but that’s another story.
Paul, I’d love for you to consider this aspect and if you find it a valid point, waste some more trees or videotape on the subject.
I had the same thing happen to me with a soaring bird on turning base. It was as if he was waiting for me to show up. I didn’t slow down, but I always look for birds when I start getting low.
In Alaska, it’s commonly called a “Moose Stall”. When the pilot’s focus is on something else. Usually attempting to hold the subject on the ground into view instead of maintaining a smooth air flow over the wings. My Alaskan Flight Instructor had me practice turns about a point over and over. He also would have his students fly to and from the practice grounds at minimum controllable air speeds. He told me “anybody can fly a light loaded aircraft at cruise speed”. “Practice gross weight slow flight maneuvers at altitude ever chance you get.” So I do.
Very nice! I will make every best effort to avoid cranial-rectumitis! Thanks, Paul for the humility that helps us learn we are all human!
I’ve often thought that it would be nice if light aircraft had the same AURAL annunciation of “bank angle, bank angle” as most transport category (Part 25 certificated) have (with exception of fly by wire where there is envelope protection) when a certain exceedance is reached. Lest one think this would be big bucks, with AHRS in GLD5x/Stratus systems commonplace and connected to an Ipad with Foreflight/Garmin app, this should be relatively cheap to implement i.e. just software. Of course I realise that such a system would be of little help if one was flying straight and level and yanked the yoke backwards past the AOA limit.
Probably drifting a bit here, but my Aeronca Chief, and I suspect some others, would not, absolutely would not stall from a slip. You could begin a forward slip with it, start pulling the yoke back, back, back, and all that would happen is you would be slipping like crazy and then eventually run out of rudder, and it would slowly just begin to turn in the direction of the slip. With the wheel in your lap and exaggerated nose high, it would just burble around the turn. All of which says nothing except base to final turns, if slipping, slow was ok. Now, a skidding turn, don’t! It would definitely stall and a sharp break over the top direction. Not good when turning final. Attempt this to see how yours does only with adult supervision and up at altitude.
Here (in a 150):
Oh yeah – if AvWeb strip off the URL – Search keywords:
youtube graemejwsmith spin off a slip
Another great video Paul, thank you. But a big takeaway for me, a low-time ASEL, is that a high timer can (A) still get lazy and (B) still fly with his head where he can see what he had for lunch. I was hoping after a few more hundred of hours I would be immune to such afflictions. It’s a lesson for me that no matter how many trees I cut down to fill logbooks I can still slip (pun intended) into bad technique. Thank you Paul for admitting and sharing your mistakes so I can learn from them.
@Brian Lloyd: Do you use the ailerons to coordinate the airplane? Maybe the folks I learned from were confused, but I was taught to use the rudder to keep the airplane coordinated and if anywhere near the critical angle of attack use ailerons carefully and sparingly.
About 63 years ago, when my old time instructor was trying to solo my dumb ass in an Aeronca, he said this about the ball and coordination. “Consider that ball to be the head of a snake. When it sticks its head out one side of the cage or the other, step on its head with that foot to put it back in.” Always remembered that and do that.
Modern flight safety philosophies embrace the idea that pilots will make errors because they are humans. The emphasis is therefore on proactively recognizing when errors could be consequential, and taking early and effective avoiding action. Critically there is also an emphasis on recovering from mistakes
With respect to Paul’s scenario the failure to recognize the distraction of looking at the hawk was the error, however the recovery was a result of the hands and feet skills that recognized the soft stick and interrupted the developing loss of control with immediate, instinctive and correct actions.
I think the flight training industry is trying to develop the the threat and error recognition piece but the problem is a continuing problem with aircraft control skills.
Weather used to be the big killer but in the last 5 years the number one cause of fatal accidents is loss of controlled flight
When training I spend time on slow flight with the ASI covered because I want the student to understand what the airplane is telling them with feel of the controls.
Technology absolutely has a place in aviation, but not in initial flight training. The manipulation of the controls based on what you feel and what you see out the windshield is the key to developing pilots who can take advantage of technology, not depend on it.
Nice video, Paul. It sparked a few thoughts for me. Air speed and AOA are both indirect indicators of an imminent stall. Neither of them measures the actual separation of air over the top of the wing that occurs during a stall. Maybe technology will come up with a better way some day. How about air pressure sensors placed at the top front, top middle and top rear parts of the wing feeding data to a microcontroller that compares them? I remember strings of yarn being taped to the top of the wing being a better indicator but that only works for low-wing aircraft and mine is a high-wing Maule MX-7-180. Vortex generators help slow down the progression of a stall. I consider mine to be one of the best investments in aircraft modifications that I have made. Some aircraft, including mine, are hard to stall and correcting a stall is as easy as relaxing the control pressures with minimal altitude loss. It’s a good idea to practice stalls at altitude in all flap configurations in a variety of bank angles to develop the automatic reaction to correcting them. I did that in my Maule in McCall Idaho in 2016 at 7,500 MSL while getting instruction from McCall Mountain Canyon Flying Seminars.