Body pain is important to humans. It keeps us from damaging our bodies. When injury begins, pain calls out to us, "Stop!" Pain is a powerful and wonderful communication tool that keeps our bodies preserved and safe from continued injury. Airplanes feel pain too. The problem is, they can't tell us what hurts and when.
Wouldn't it be great if airplanes could talk? "A little more right rudder, please. There, that feels better." Airplanes do sometimes communicate, but in much more subtle ways. As pilots, our primary means of understanding and working harmoniously with our ship is through knowledge. Knowledge of what hurts airplanes, what keeps them safe, what stresses them, and how best to handle them. It's a synthetic thinking game, kind of like aliens from a different galaxy reading a manual about how to decode human body language. "I wonder why the corners of their mouths point up when they're happy," they might say. I've often wondered what an airframe feels during a steep turn. All the rivets, the wing spars, the skin creating different artificial sensations. The problem is, we can't feel those sensations, yet we're very much a part of the airplane and are totally reliant on its structure to remain intact and healthy during flight.
So, we learn in ground school about load factor and aerodynamics, much like aliens would study human anatomy and physiology to better understand our inner workings. But until the day when it's possible to hook electrodes onto our arms and legs that zap sensory information into our bodies in accord with airplane loads and stresses during flight, the best we can do is put knowledge in our brains about what it must feel like for the airplane.
Sometimes we misunderstand or forget. This is what brought down AAL 587, an A300 that crashed during climbout from JFK in 2001. The airplane encountered wake turbulence from a 747 a few miles ahead and the pilot made over-enthusiastic control inputs that ripped the vertical stabilizer off. If only the airplane could've shouted out to the pilot, "Ouch! That hurts! Less rudder!" Since we can't feel the airplane's pain, it's impossible for us to tell when the beating is becoming too severe until it's too late and structural failure occurs. For this reason, we must be extra vigilant and cognizant of our flying technique. Stick and rudder skills are still important, even in this age of automation. Pilots can still break airplanes. A thorough understanding of aerodynamic principles is imperative because we can't be guided by the airplane's sense perceptions, although the airplane is feeling every input continuously.
Be kind to your airplane. Fly it gently, gracefully, and with care and expertise. It will appreciate it, even if it can't tell you with words.
