If you ask pilots of any experience level what makes a wing stall, I guarantee you’ll get a consistent answer: “Exceeding the critical angle of attack.” This, of course, is correct, and it is information that is ingrained into our flying brains from the first day of Private Pilot ground school. The logical follow-up question, “How do you recover from a stall?”, also yields a consistent and correct answer: “Lower the nose to decrease the angle of attack.” I can say these questions are answered consistently because I ask them of every student I’ve ever taught in university ground schools, from Private Pilot to Instructor Pilot, and they always give me the correct responses. This says nothing of my teaching, rather, it points to the fact that pilots of all stripes know this intuitively. A wing stalls when it exceeds its critical angle of attack (AOA), and to recover from a stall one must decrease the AOA. If this is intuitive, why then do so many pilots kill themselves by doing the exact opposite at the one moment in their lives when all the stall training they’ve undertaken actually counted?
Loss of control inflight (LOCI) due to an aerodynamic stall/spin continues to be the number one killer of general aviation (GA) pilots. This statistic does not discriminate; pilots of all ages and experience levels have fallen prey to the LOCI monster. It’s a great mystery given the amount of stall training and evaluation pilots undergo in their quest for freedom aloft, and it begs the question: is something missing from our training? I’ve scratched my head over this one for years, even as I’ve taught spins to instructor pilot candidates, imparting on them the tremendous responsibility they will bear to ensure their future students never commit such a deadly error. Under what circumstances are pilots finding themselves in uncontrolled stalls or spins from which they are unable to apply their training in order to recover?
Advisory Circular 61-67C Stall and Spin Awareness Training attempts to answer this by pointing to National Transportation Safety Board (NTSB) statistics indicating that distractions are the leading culprit of stall/spin accidents. As far back as 1980 the FAA announced its policy to incorporate distractions during the performance of flight test maneuvers. So there’s the answer – distractions. But that’s a vague term, and it doesn’t do enough to explain how a pilot loses control. Dropping a pencil in the cockpit, looking for traffic, jotting down a clearance, or even losing an engine on takeoff should never lead to an unrecoverable stall. This answer – distractions – doesn’t go far enough to explain what’s really going on; therefore, I began to search for something more specific, and I may have found it.
I think the answer may lie deeper in the realm of psychology, and I can point to two different tragedies that provide a clue; one involves a pilot, the other a police officer. In my Aviation Safety class at Minnesota State University, Mankato we discuss Colgan Flight 3407 in great detail. This crash of a regional airliner in February 2009, killing 49 onboard and one on the ground, ignited a flurry of new regulations ordered from on high by Congress and President Obama when he signed the Airline Safety and FAA Act of 2010. Examples include the requirement for first officers of Part 121 airlines to hold an Airline Transport Pilot (ATP) certificate, specific requirements for more rigorous ATP training, the requirement for airlines to review training records when hiring new pilots, and on and on. Because so many of these new regulations affect the careers of my students, I felt it was important to take a deeper look into what really happened on that fateful Colgan flight. What I found shocked me.
In summary, the captain stalled the airplane while intercepting the localizer for the ILS 23 approach into Buffalo, NY. How he stalled it is the shocker, but it may also provide the clue that explains all the other LOCI accidents mentioned above. I will forgo the details (anyone can access the full report online) and just take you to the moment when the captain responded to an artificial stall warning called the Stick Shaker. This system is used on larger airplanes to mimic the stall buffet at speeds generally five to eight knots above the stall. The stick shaker on this flight caught the captain by surprise because it activated much sooner than expected, and the captain responded by pulling back on the yoke. Let me repeat that. When warned of an impending stall, the captain pulled. This captain, holding an ATP certificate, would’ve undergone countless stall training throughout his career, from Private Pilot to his current level, knowing intuitively that a push is required to lower the AOA. Why did he pull?
Herein lies the clue. The NTSB report of this accident contains a detailed transcript of conversations and other sounds picked up by the Cockpit Voice Recorder (CVR), with each sound time-stamped to the tenth of a second. It also adds elements of flight control inputs gleaned from the Flight Data Recorder (FDR). At 2216 and 27.4 seconds the stick shaker activated. At 2216 and 27.8 seconds the control column moved aft. That’s 0.4 seconds. In other words, this pilot responded literally in a split-second to the stick shaker. The artificial stall warning startled him, and without thinking his muscle memory kicked into gear and he pulled on the yoke. Why? Because pulling generally gets us away from the ground and all the dangers associated with that. I think this is analogous to someone stomping on their car’s brake pedal at the first indication of a skid when that is often the worst thing to do. But the brake pedal usually brings us to our happy place; it stops the car and the danger is averted. The foot goes there automatically, without any connection to the brain. In an airplane pulling back on the yoke or stick brings us to our happy place, further from the ground and further from danger. This is also something we learn from day one of pilot training, and for the Colgan captain it was perhaps this muscle memory that overcame the appropriate response of pushing to reduce the AOA. This pilot may have committed something called “Action Error”, and that leads me to the story of a police officer.
The reader might remember the tragic shooting and killing of a young man in April 2021 by a police officer who had mistaken her firearm for a taser. This occurred in Brooklyn Center, MN less than a year after the death of George Floyd. Racial tensions were high, so this occurrence and the subsequent trial of the officer involved made front-page news. My interest in this tragedy piqued when I heard the defense arguments offered by the police officer’s attorney. In the heat of the moment, when the young man jumped back in his car to escape arrest by speeding away, the officer yelled “Taser!”, intending to use non-lethal force to stop him. But muscle memory kicked in and her hand reached automatically for her firearm. This action error, as explained by an expert witness on her behalf, occurs in high stress situations, and the hands, unconnected from the brain, will revert to the predominant action for which they’ve trained. The witness even pointed to aviation accidents, or mistakes in surgery, as prime examples. In the officer’s case the majority of her weapons training involved her firearm versus her taser, so that’s where her hand went.
In flying, as much as we practice stalls, the predominant behavior our hands learn is that pulling equals climbing. On every flight, for example, we always pull at rotation speed to get away from the ground. The captain of Colgan 3407, when faced with an impending stall while IFR at night and relatively close to the ground, suffered a disconnect between his brain and hands and pulled on that yoke for all his might. In fact, he even pulled against the Stick Pusher, another safety system designed to help a pilot lower the nose in a stall. The stick pusher, in this case, activated three times, and at each successive activation the FDR indicates a stronger and stronger pull by the captain, culminating in 160 pounds of aft force applied during the third activation. That’s a lot of panicked yanking on the yoke to get away from the ground that was rapidly rising to meet them.
This could provide the clue as to why so many other pilots may have done the precise wrong thing when entering a stall near the ground, pulling rather than pushing while falling to their deaths. In my search for the answer I took a deep dive into the NTSB database, looking for all general aviation accidents that resulted in a fatality due to an aerodynamic stall/spin. My goal was to find the smoking gun, a common trigger event such as the Colgan stick shaker that caused these pilots to go against their training and misapply the proper stall recovery procedure. The problem with GA accidents is the scarcity of information available for the NTSB to analyze. An average GA aircraft isn’t equipped with a FDR that can provide details such as control inputs and control force applications. Oftentimes the only information available is the wreckage itself, or eyewitness testimonies. Finding the smoking gun proved to be futile. Nevertheless, the NTSB does a fine job of piecing together all available information, usually culminating in a detailed eight to ten-page report. This information may provide enough clues to guide future thinking regarding stall training.
In analyzing these reports I’ve discovered a few commonalities that point to my theory. A review of the 100 most recent fatal stall/spin accidents since the time of this writing (going back to 2017) reveals that 90% resulted from a stall that occurred less than 1000 feet above ground level, and most of these (81%) were in the vicinity of an airport. Additionally, the weather almost never played a factor with 94% occurring in Day VMC and with excellent visibility and high ceilings or clear skies. Experience levels of the pilots committing these fatal errors were all over the map. This was not a discriminator; something else was going on. I believe these pilots, distracted by something in relation to the runway or airport environment (an engine failure after takeoff, for example), stalled their airplane, and once the stall occurred, they were caught by surprise and pulled all the more. In other words, the initial stall wasn’t the culprit; rather, it’s what happened immediately after. Because they were so low to the ground (<1000’) an element of stress kicked in and they committed a similar action error as identified in the trial of the police officer, and in the case of Colgan 3407. With the ground rushing up to meet them, they pulled with all their might to get away from it when a push was necessary to recover. It is counter-intuitive to push when near the ground, but a sacrifice of altitude is necessary to get the airplane under control.
This theory may not apply to all LOCI accidents resulting in a fatal stall or spin crash, but given what we know about the Colgan flight it is reasonable to assume that other pilots behaved the same way. That is, they ignored their training and pulled. And that leads back to the question posed earlier: is there something missing from our training? According to the Private Pilot Airman Certification Standards (ACS), pilots are evaluated on their ability to “configure the airplane, establish a pitch attitude that will induce a stall, and execute a stall recovery”, among other things. In other words, stalls are predetermined maneuvers as specified by the evaluator. There is no element of surprise to evaluate a pilot’s muscle-memory response to a startle-stall. Of course, this is something that would be difficult, if not impossible, to train and evaluate safely. Technology could be used, such as programming a flight simulator to stall at an unexpected moment while close to the ground, but in a flight simulator the fear element is absent (there’s no fear of actually dying.) Such is the case also when practicing stalls in an airplane at a safe altitude (minimum 1500’ AGL.) And it’s difficult to surprise a pilot with a stall in an airplane. Without those two elements being present – surprise and fear – action error may never surface.
The point is not to supplant today’s method of stall training, which is significantly valuable. Pilots must learn as a primary skill to recognize the behavioral characteristics of their aircraft before, during, and after a stall, and to recover from stalls with the airplane under control. I am merely suggesting that we explore new methods to augment existing stall training and evaluation. Can we do more on a checkride than just evaluate pre-canned power-on and power-off stalls? This would require additional research and testing by FAA working groups and steering committees, but something has to be done to reduce the still significant number of fatal LOCI accidents.
In the meantime, nothing prevents individual pilots from seeking additional skills in aircraft handling. In fact, I believe any training that involves maneuvering an airplane outside of normal parameters – aerobatics, spins, upset recoveries – is extremely valuable. The airplane used for this specialty training may have different handling characteristics than what most GA pilots fly, but there is direct application when considering the confidence gained as a skilled aviator. Upside down is upside down, whether in a Piper Cub or Pitts Special. Pilots should get comfortable getting uncomfortable so that when an abnormal situation occurs – a surprise stall low to the ground, for example – they do not panic. Such training should also incorporate muscle-memory: learning easy steps that can be taken home and practiced on the living room sofa (i.e. chair flying) so that action error never sneaks up on an unwary pilot.
Regardless of whether or not one invests in the specialty training suggested above, every pilot should take their stall training very seriously. Stalls should never be square-filled items on a checklist – complete them and then move on to the next maneuver – and they should always be trained for more than just meeting the standards set forth in the ACS. With a qualified instructor pilot, and at a safe altitude, stalls can be practiced in many different scenarios. Slow speed acceleration stalls, secondary stalls, deep stalls, trim stalls, cross-controlled stalls (with an appropriate aircraft) and many more are all valuable when training and building muscle memory. If every pilot heeded the above suggestions, I’m convinced LOCI statistics would drop significantly. This is how not to lose control, according to what we can learn from Colgan 3407.
- How Not to Lose Control: What We Can Learn from Colgan 3407 - June 5, 2023