Monday, 19 March 2018
Acknowledgements: Rod Machado’s Aviation Learning Centre (https://rodmachado.com)
(Ed.Note: More wise words from Rod!)
You’ve heard this sad tale before: Forty hours of dual instruction, with over 200 logged landings - and Bobby still can’t land an airplane. Bobby is in such despair that his instructor resorts to special motivational phrases to buoy his student’s spirits: “OK Bobby, not bad. You’re missing the runway closer now!”
Why would someone with over 200 landings be unable to land an airplane? If we assume average intelligence, and reflexes fast enough to avoid an onrushing glacier, learning to land shouldn’t be difficult at all. What going on here? Let me explain by taking you back in time, about seventy-six years.
In 1940, the Civil Aeronautics Administration (CAA) conducted an experiment to determine the average time required for “zero-time” students, ranging in age from 18 to 46 years, to solo an airplane. These students, who came from all walks of life, were divided into two groups.
One group trained in a Piper Cub having tailwheel gear, conventional for that time period. The other trained in Fred Weick’s recently created Ercoupe, which was the first small airplane to have tricycle gear. It also had a two-axis control system (i.e., no rudder pedals) that coordinated both rudder and aileron control movement.
The CAA experiment revealed that the students training in the Piper Cub took approximately eight hours to solo, while those training in the Ercoupe soloed in 4.3 hours. One student even soloed in 2.2 hours in the Ercoupe (years ago I soloed a zero-time student in an Ercoupe in 4.5 hours, at a tower-controlled airport). Apparently, when rudder pedals weren’t needed to fly an airplane, learning to fly became amazingly easy! The results of this experiment even motivated the CAA (at that time) to reduce the private pilot certificate requirements in a two-axis control airplane from 32 to 25 hours.
Of course, you might argue that taildraggers are more challenging to land than tricycle-geared airplanes. That’s true. However, until the main wheels of both types of landing gear touch the runway, the control inputs required to round-out and flare either airplane are essentially the same (assuming you touch down close to stall speed). The real challenge with landing a taildragger is using the rudder pedals to keep the airplane’s nose pointed straight down the runway after touchdown (which isn’t an issue in an Ercoupe). Therefore, it’s the need for rudder usage (on the ground and in the air) that makes the Cub more challenging to land than the Ercoupe.
The CAA’s experiment suggests that learning how to round-out and flare is not the main challenge students face prior to solo. After all, students in the Ercoupe probably spend 2.1 hours in the practice area and 2.2 hours in the pattern learning to land. Those 2.2 hours most likely result in an average of twenty touch-and-go landings before solo. Cub students most likely needed 4 hours of landing practice prior to solo.
Here’s the conclusion I’d draw from this observation: Most any student can learn to land an Ercoupe in a little over two hours. They can also do the same thing in a tricycle-geared airplane equipped with rudder pedals, but only if they have developed good rudder skills before they begin landing practice.
Without good rudder skills, students in three-axis control airplanes can’t control the direction the airplane’s nose points while landing. Now they must divide their conscious attention between keeping the airplane over the runway, as well as controlling their height above. Good rudder skills acquired before landing practice begins allow students to focus all of their attention on learning how to round-out and flare.
The wonderful news is that anyone (students or rated pilots) can acquire reflexive rudder skills on a desktop flight simulator that has a yoke and rudder pedals. Begin by setting the simulated airplane on a half mile final at 500 feet AGL at approach speed. Select severe turbulence and maximum allowable runway-aligned winds from the weather menu, and then uncheck the auto-coordination feature. Save this simulation for repeated use.
Get to it. Practice flying. Keep the wings level with the ailerons, and the nose straight with the coordinated use of the rudder as you descend for landing. Right aileron, right rudder; left aileron, left rudder. No exceptions. Repeat the sequence over and over again until your legs fall off (or you get tired, whichever hurts less!) You’ll know you’ve acquired basic rudder skills when you level a turbulence-displaced wing and the nose doesn’t yaw one micron. Now you’re ready to set foot in an airplane … assuming your foot is still attached, of course!
Acknowledgements: Rod Machado‘s Aviation Learning Centre (https://rodmachado.com)
(Ed. Note: Thanks to Rod for permitting the use of some of his material as part of our blog!)
“This article 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. Everyone knows someone who has stalled and spun when making right-hand patterns. That, however, is irrelevant if stalls and spins occur more often in left-hand patterns.
There are several aviation experiments underway which 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, but I’m not one to criticise without offering an alternate and perhaps more practical way to reduce stall/spin accidents in the pattern.
My proposal 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.
But 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 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.
Let me explain. It turns out that today’s pilots tend to favour power-on approaches rather than power-off approaches. That’s because the FAA does not discourage general aviation pilots from flying small airplanes in a similar way to how airline pilots fly their larger airplanes (i.e., make long shallow stabilized power-on approaches). But 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 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, as 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. 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. Both the turn and the stalled left wing are acting in the same direction and often produce a quick spin entry to the left.
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, 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.
In this instance:
· Should the airplane stall, it might stall in a right slipping turn where the outside left wing stalls first and the airplane wants to roll opposite to the direction of turn.
· 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.
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 is likely to be less lethal for pilots who’ve lost, or never had, any significant degree of proficiency with their rudder pedals. I'm not saying that pilots can't spin out of a right, powered turn to final approach. Just that a spin out of a left, powered turn to final approach is more likely if pilots fail to use their flight controls properly.
Objection your Honour! No doubt you’re thinking that flying a right-hand traffic pattern from the left seat makes the runway harder to see on the downwind leg and when turning final approach. Well, 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. Problem solved! Flight controls can do many things to please a pilot.
In my opinion, the proper solution to prevent loss of control accidents (stalls and spins) in the traffic pattern is better training. Changing the behaviour of the pilot community, however, is a very difficult task. But, 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 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, simply by changing the direction that pilots manoeuvre about the runway when landing”.