By Rod Machado
NOTE: I post these articles, in particular this one, in hopes of receiving some well reasoned input. This article presents an hypothesis that needs testing. Nearly every response so far suggests that pilots should be taught to fly coordinated instead of making right patterns standard as a means of reducing the stall/spin risk. Well, of course pilots should be taught to fly coordinated (as I've advocated for decades). This piece, however, isn't about changing the pilot. It's about changing the environment in which a pilot flies to reduce the risk of flight. One is completely unrelated to the other. Saying that we shouldn't change the environment to make flying safer is very similar to saying that we shouldn't have air bags in an airplane because the pilot should train his body to withstand the impact of a crash. We change the environment (add airbags) to make the pilot safer in addition to promoting proper pilot skills. Finally, you may actually know someone who stalled and spun when making right-hand patterns. That, however, is irrelevant if stalls and spins occur more often (per-hour or circuit flown, or something) in left-hand patterns. So I look forward to any comments you might offer in support or rejection of this hypothesis.
We take a big risk when offering ideas that contradict long-standing traditions. In a sixth-grade Catholic school class, I suggested that God would get some good vibes from humanity if he graded everyone on a curve. The head nun was “nun” too happy with my suggestion and threw a shoe at me. Unfortunately, it still had a kid in it. So, if you elect to toss footware in response to the following hypothesis, please remove its current occupant before doing so.
As you know, there are several aviation experiments underway that are attempting to find new and novel ways to reduce stall/spin accidents in the traffic pattern. One of these involves making a 180-degree circle–to–land approach in the hopes of eliminating a skidding turn onto final approach—a turn that could result in a spin should the airplane stall. Since I’ve already written about the impracticality of this idea I’ll say nothing more about it here. On the other hand, I’m not one to criticize without offering an alternate and perhaps more practical way to reduce stall/spin accidents in the pattern. Here’s a proposal I made many years ago that, at the time, seemed to go over like a pregnant pole-vaulter. Perhaps I’ll find a more sympathetic ear with this submission.
My proposal for reducing pattern stall/spin accidents is simple: Make right-hand traffic the standard pattern flown by pilots instead of left-hand traffic as recommended by the FAA. There’s a good “common sense” argument to be made about why flying right-hand patterns is actually safer. Let me explain.
It turns out that today’s pilots tend to favor power-on approaches rather than power-off approaches. That’s because the FAA does not discourage general aviation pilots from flying small airplanes similar to how airline pilots fly their larger airplanes (i.e., make long shallow stabilized power-on approaches). Flying power-on approaches means that small airplanes will have greater exposure to the left yawing tendencies associated with torque, P-factor, and propeller slipstream. As power and angle of attack increase, airplanes that are not properly flown are more likely to skid during left turns to final approach and slip during right turns to final approach. If you’ve cracked even one book on aerodynamics over the past decade, you’ll know that stalls while skidding are more likely to result in a spin than stalls that occur while slipping. Let’s look closer at the details.
Stalling From an Uncoordinated Left Turn Onto Final Approach
When pilots turn onto final approach from a left base leg, they tend to skid the airplane’s nose toward the inside of the turn because of improper control use. How so? Rolling out to the right without the proper use of right rudder yaws the airplane’s nose to the left, toward the inside of the turn. This is called a skid. If the pilot overshoots the turn and pulls aft on the elevator control to compensate for the overshoot, he’ll have to hold right aileron to prevent the bank from increasing. Using right aileron in either situation results in adverse yaw pulling the airplane’s nose toward the inside of the turn. Should the airplane’s wings approach their critical angle of attack, the left wing (the wing inside the turn) will likely stall first. After all, a left yaw pulls the left wing aft and slows it down slightly compared to the right wing. Therefore, its angle of attack is slightly larger than the right wing’s angle of attack. If the left wing stalls first, the airplane will roll to the left, in the same direction the airplane was turning. The left yaw, in this instance, is exacerbated when power is used for the approach (which it is most of the time). When the left wing stalls first in a left turn, both the turn and the stalled left wing are acting in the same direction and often produce a quick spin entry to the left. While you might be able to run a Rosary through your hand as quick as the ammo belt on a machine gun, it’s unlikely you’ll get through even one bead before you and your airplane become landmarks. On the other hand, stalling and spinning from a right turn onto final approach is much less likely to result in a spin. Let me explain.
Stalling From an Uncoordinated Right Turn Onto Final Approach
Turning right onto final approach from a right base leg results in the exact same amount of adverse yaw produced by the ailerons as compared to a left turn onto final approach. Failure to use rudder while rolling level from a right turn or holding left aileron to prevent a bank increase during a turn results in the nose yawing toward the inside of the turn to the right. This is the same skid that we just discussed in the previous paragraph, except that it occurs to the right, not the left. The big difference here is how power affects the airplane. The use of power yaws the airplane to the left, especially at high power settings and high angles of attack. Therefore, in a right turn to final approach where the pilot fails to use rudder properly, power pulls the nose to the left, toward the outside of the turn (known as a slipping turn). In this instance, should the airplane stall, it might stall in a right slipping turn (i.e., the left [outside] wing stalls first and the airplane wants to roll opposite the direction the airplane is turning). Then again, if the power-induced left yaw and the adverse yaw (to the right) counteract each other, the airplane might stall in a more coordinated flight condition. Either way, an airplane stalling in either condition is less likely to spin and more likely to simply pitch in a forward/downward direction as it would in a typical stall without the extreme rolling and yawing motion of a spin entry. Ultimately, flying a right-hand turn to final (as opposed to a left-hand turn) is likely to be less lethal for pilots who’ve lost (or never had) any significant degree of proficiency with their rudder pedals. (And just to be clear here, I'm not saying that pilots can't spin out of a right, powered turn to final approach. I am saying that a spin out of a left, powered turn to final approach is more likely if pilots fail to use their flight controls properly.)
You’ve Got to Be Kidding Me? Where's My Shoe?
Now, hold on rocket pants. Keep your shoes on. I know you have objections and I want to handle them. Let’s take the big one, first.
No doubt you’re thinking that flying a right-hand traffic pattern from the left seat (where pilots normally sit) makes the runway harder to see on the downwind leg and when turning final approach. Well, it might indeed make the runway a little harder to see on the downwind leg. Then again, I’ll bet that you’ve never complained about not being able to see the runway when flying right traffic from the left seat. Why? Because you’ll fly a slightly wider pattern to provide a view of the runway that pleases you. Yes, you can actually manipulate your controls so as to produce the desired view of the runway. Flight controls can do many things to please a pilot.
As far as not being able to see the runway as clearly in a right turn to final from the left seat, I think you need to think a second time about this. First, if this idea had any merit, it would only apply to high wing airplanes, not low wing airplanes. So, your concerns are immediately reduced by 50%. Furthermore, as a CFI, I sit in the right seat and fly a lot of left traffic patterns. When sitting on the right side of the airplane, I can always see the runway easier, earlier and from a better perspective (when turning from base-to-final) than my left-seat student when flying left traffic in a high wing airplane. So, neither of these objections are shoe worthy.
“But wait,” you say, “what about those airports where you can’t fly right traffic because of obstructions, environmental concerns, or noise abatement?” Well, if right traffic isn’t practical for some reason, then—wait for it, wait for it—you don’t fly right traffic. Period. In Spanish, we have a phrase for that: Tough Taco. We can’t always get what we want. All I’m saying is that, should my hypothesis be proven correct, we should make right patterns standard so that pilots will fly right traffic more often.
In my opinion, the proper solution to prevent loss of control accidents (stalls and spins) in the traffic pattern is better training. I've advocated this position for decades, and still do. Changing the behavior of the pilot community, however, is a very difficult task. On the other hand, if flying left traffic makes stall/spin accidents more likely, then it makes sense to eliminate or reduce that condition if at all possible. The genius inventor, architect and futurist Richard Buckminster Fuller once suggested that he didn't try to change the way people behave. Instead, he found it to be more effective to change the environment in which people operate. Ultimately this results in people changing on their own. Perhaps we might substantially reduce pattern stall/spin accidents by changing the environment in which pilots fly. This might even be something as simple as changing the direction that pilots maneuver about the runway when landing.