
In everyday flying, most pilots value a predictable, controlled flight (we are not talking about thrill-seeking “flying cowboy” stuff here). When you put the chocks on the wheels and there have been no “surprises” we usually succeeded in our mission. One flight last fall was notably different though, involving a wake turbulence encounter at 16K deadheading into Chicago Executive.
This unannounced, surprise encounter rolled our jet 70 degrees to the left and put us 20 degrees nose down (with a view of just Lake Michigan) in only a second or two with all the lights and alarms. The negative G force totally trashed the cabin (if there had been unbelted pax in back they would have been severely injured). The 20lb pilot handbook on my left even became airborne and bruised my legs when it ended up in my lap. Fortunately, automatic training took over and standard “power to idle, roll wings level” restored normal flight (we lost 1200 feet and were going rapidly to over-speed – sorry to ATC!)
One continuing enigma in aviation safety is the fact that though all part 23 and 25 aircraft are, by regulation, designed “nose heavy” to recover stability by pitching down in response to an excessive AOA (stall or loss of lift), humans predictably overpower this safety design by pulling back when encountering a stall creating most of the problems.
“STARTLE FACTOR – CLUTCH REFLEX:
The answer is simple, we are all Human! As humans we have walked around on earth for a long time at 1 G. None of us like to fall down, when we do fall, we always clutch or brace ourselves, falling induces a sensation of less than 1 G. Take an infant moments old, subjected to a slight down motion causes them to startle and cry. This is called the moro reflex, and while its called “startle factor” or “clutch reflex” in an adult, the reflex remains with us our entire life. By the way, there is no crying in stunt flying! With proper de-sensitivity training to the 1/2 G experienced during a stall I believe we could almost eliminate the occurrence of spin accidents.
It is the startle factor (clutch reflex) that is responsible for taking an airplane that has been initially upset and turning it into a spin. The involuntary clutch reflex on the yoke as the airplane is pitching down stalls the wing even more. Additionally, if there is any roll motion the pilot will involuntarily deflect the ailerons to raise the low wing, inducing adverse yaw and drag and stalling the wing deeper on the aileron that is deflected down.” Allan Moore
Though startle is covered in a recent GAJSC startle handout, and there are many articles written on the subject, reading alone will not create inoculation. You must fly and experience and actual negative G force and resulting disorientation. It is essential to feel your body’s ancient, visceral reaction to this experience to understand it fully. “Startle effect” can render any pilot helpless and incapable of effective action without some previous and recent experience (see a comprehensive analysis here). This surprise bodily reaction and loss of cognitive bandwidth from the fear and adrenaline is shocking.
SAFE CFI-PRO™ workshop
Join SAFE to support our safety mission of generating aviation excellence in teaching and flying. Our amazing member benefits pay back your contribution (1/3 off your ForeFlight subscription)! Our FREE SAFE Toolkit App puts required pilot endorsements and experience requirements right on your smartphone and facilitates CFI+DPE teamwork. Our CFI insurance was developed by SAFE specifically for CFIs (and is the best value in the business).