Monday, July 23, 2012

Frame of Reference

Many a student pilot has asked, aloud or to themselves, "When will I get really comfortable demonstrating stalls?" and the best answer is "Hopefully, never." Unless you're an aerobatic performer or a flight instructor, intentional stalls are abnormal events. Feeling a certain amount of anxiety or discomfort with stalls is common among pilots regardless of their level of training. Pilots train to do stalls and stall recovery so we can demonstrate an understanding- and application-level of knowledge during a check ride. And stall demonstrations are required on check rides because - surprise, surprise - pilots continue to kill themselves, their passengers, and people on the ground in stall/spin accidents.


Three stall-related accidents involving professional flight crews that occurred in the last few years may explain the FAA's recent changes in how stalls are to be demonstrated in Private Pilot and Commercial Pilot practical tests. Two of the accidents are familiar to most pilots: Colgan Air 3407 and Air France 447. A third accident, Empire Air 8284, garnered less attention perhaps because the aircraft was destroyed yet the flight crew escaped with their lives. What all three accidents share are a flight crew, made up of pilots who had gone through numerous check rides and, one would assume, numerous stall demonstrations, who allowed their aircraft to enter an aerodynamic stall.

Like many accidents, the Empire crash involved multiple factors - icing conditions, asymmetric flap extension, a contaminated runway with crummy braking action, and a captain who seemed committed to getting the aircraft on the ground. Watch the simulation of the accident and you'll find it eerie that the pilot flying (first the FO, then the captain) appeared to adjust power and airspeed for a normal approach to landing instead of what was essentially a no-flaps landing with a contaminated wing.

People learn to fly for a variety of reasons, but it's reasonable to conclude that student and certificated pilots tend to be goal-oriented people: They want to learn something challenging and, by doing so, exhibit skill, confidence, and competence. Becoming a pilot is deeply intertwined with self image, but some pilots may have a need to prove themselves in a way that goes beyond the average desire for recognition. Perhaps they are secretly afraid of flying and in a reaction-formation sort of way are trying to free themselves of their fear. Whatever the reason, they want to convince themselves and those around them that they are not afraid. The problem may not be fear, but the fear of being afraid.

Discomfort with stalls can lead pilots to try to fight fire with fire. They may put themselves or their students on a steady diet of stalls in a desire to build confidence. They may undertake aerobatic training (not a bad thing, in itself) or specialized upset training. This sort of training may lead to unintended consequences, what the FAA refers to as an operation pitfall - flying outside the envelope in non-aerobatic aircraft. I was going to link to a video of a hot dog in a Citation doing an aileron roll, but it's been removed by the poster. Whatever mechanism is at work, accident history indicates that spin training and upset training does not immunize a pilot from being involved in a stall-spin accident. The pilot may feel enhanced self-confidence, but that does not necessarily translate into a safer pilot.

So the FAA has changed the language used to describe stalls in the Private Pilot PTS to "fully-developed stall," which makes sense because early training experiences make a strong impression, two characteristics that flight instructors should recognize as the Law of Primacy and the Law of Intensity. These early experiences in stalls are mimiced in larger aircraft by stick shakers and stick pushers - equipment designed to remind a pilot they are dangerously close to an aerodynamic stall by tapping into their earliest flight experiences.

When a pilot transitions to commercial training, the goal is not to prove courage with regard to stalls but, rather, smarts in avoiding stalls altogether. And so the FAA changed the language used to describe stalls in the Commercial Pilot PTS to "onset (buffeting)." And commercial pilot applicants are now required to demonstrate accelerated stalls and, to the FAA's credit, the PTS contains a clear and concise description of how these stalls are to be demonstrated.

This is a step in the right direction because stalls can involve multiple variables - angle of attack, airspeed, load factor, aircraft configuration and wing contamination - and these variables may not be fully understood by an overloaded pilot or flight crew in the moment. Yet even with these changes, it's likely that stall-spin accidents will continue to occur because flight training often involves artificial and highly choreographed maneuvers that may not prepare pilots for real-world stall situations.

The only PTS that requires an applicant to demonstrate a variety of stalls - trim, cross-control, accelerated, secondary - is the flight instructor PTS. If private pilots (or at least commercial pilots) were required to be familiar with all of the stalls that flight instructors are required to know, it could significantly reduce the trend in stall/spin accidents. If you're a pilot who wants to deepen your understanding of stalls, there's no need to wait for the FAA to act. Ask an instructor to teach you all the stalls they were required to know for their flight instructor check ride. And if you feel nervous or anxious with any or all of these stalls, that's okay. Stalls are abnormal events and if you never experience one during normal flight operations, you're not a chicken, you're smart.

4 comments:

capnaux said...

Good stuff, John.
I've been going round in my head on this one, first trying to figure out how pro pilots could forget such a basic maneuver--it's like an adult forgetting how to crawl after having learned to walk!

I always taught spins to my students, regardless, to both get the fear out of them and to recognize them.

Our airline has "gone back to basics" as well, drilling us with stall and upset recovery--more than we have in the past, anyway. I imagine at this level it's just a matter of recurrent training.

Terence Wilson said...

Great insights John. My first stalls and spins were in a 152 and it sacred the hell out of me. Perhaps we should be teaching the mechanics of stall and spin recovery in a simulator before subjecting students to the real thing. Or.. perhaps we should be teaching basic stick and rudder skills in a simpler aircraft.

Stalls in gliders are generally benign, everything happens so slowly, even spinning is slow. Adverse yaw? It is so pronounced in most gliders the student can see the nose lagging the turn. Contrast with airplane students trying to get that bobbling ball between the lines with their feet.

Ron said...

I've always felt it was critically important for students to become comfortable flying at high angles of attack. In my experience, if they are afraid of them, they will be reticent to fly slowly, and this often leads to inordinately high approach speeds and other issues.

Much like @capnaux, I have a hard time understanding how so many professionals could display such poor airmanship.

If stalls and spins are scaring students, perhaps the instructor is not approaching them properly. Just throwing a student into an unannounced spin is incredibly poor instructional technique. I've spun thousands and thousands of times with countless students, and without exception they've always gained comfort and confidence from the experience.

Done right, such training will prevent stall & spin accidents, not cause them.

John Ewing said...

Capnaux,

I think you bring up a good point about recency of experience. When I'm on the receiving end of a flight review or IPC, I actually want the instructor to challenge me. Unfortunately there are many pilots out there who are content to have a "pencil-whipped" flight review or IPC.

Ron,

As in the past, we're going to have to agree to disagree about spin training as it relates to stall/spin accidents. The accident history and statistics simply don't support the claim that spin training makes safer pilots. The reason may well be human psychology.

I recently read an interesting discussion about self-confidence and performance in accomplished athletes who were "interviewing" for Cirque du Soleil. While there was a strong correlation between a candidate's perceived self-confidence and their ability to perform, some athletes who scored high on self-efficacy ended up getting injured. This was presumably because they had an unrealistic beliefs in their abilities to perform.

Anxiety and a certain level of discomfort around some flight maneuvers is normal and perhaps even healthy. I also believe that more varied stall experience (trim, cross-control, accelerated, and secondary) could help the average GA pilots to have a better appreciation for all the factors that can go into a stall - the vaunted "correlative level of knowledge." They may not be completely confident, but they could be better educated.