In the process of learning to fly, we come to regard our aircraft as pretty stout machines. After all, airframe hours are tracked into the thousands, and occasions of pilots younger than the planes they are operating are more common than not. As if to prove the point, we are taught that normal category aircraft are certificated to handle 3.8 times their weight downward (positive) and 1.52 times their weight upward (negative) and that those in the utility category can withstand far more. If we require any further convincing of their sturdiness, it is usually cemented with each repeated bang onto the runway, as we attempt to acquire landing finesse in one touch and go after another. It’s only when we handle an individual aircraft part that we gain some insight into how fragile airplanes actually are. Almost invariably, aircraft parts are lighter than our experience with ordinary mechanical components teaches us to expect. That sensory surprise triggers the first hint of understanding that every aircraft part has been made as light as possible and only strong enough to exactly react the expected design-for forces. The converse of this insight is that such parts will not long withstand an inappropriate force. My shorthand expression to capture this sentiment is, touch the plane as little as possible when you fly, because every time you do, makes it more likely to break.
Nowhere was this reality brought home to me more succinctly than with the operation of aircraft doors. I’m ashamed to admit it now, but I was once a door slammer. It’s how I was taught. Training aircraft were typically old, and airframes could become warped such that doors fit poorly, not to mention balky latch designs and dubiously maintained door seals. A short but firm slam was often the most effective technique to persuade an uncooperative door – or so I was told, and the number of times I have witnessed this frightful technique suggests I was not alone. In the Friendship Flyer, new door seal made it more important than before to pull in on the passenger when engaging the locking handle. Failure to do so created extra friction between the locking pin and the door frame latch, which could be overcome with greater pressure on the handle. The additional pressure began to deflect the connecting rod in the door and as it bowed, the friction would increase, requiring yet more pressure to overcome. The cycle of increasingly forceful operation continued until the threaded end of the connecting rod, intended only to transmit axial load, sheared off from the excessive lateral force. Replacement was complicated because the rod is not a stocked spare and required a degree of luck to be sourced from salvage.
Contributing to this kind of undesirable behavior is the fact that sometimes doors and other things do develop issues that make their operation more difficult, however, most often in aviation, I find that technique, rather than force, is the appropriate response. Training to stop and reassess when resistance is met, or response doesn’t match expectations, takes practice and presence of mind, but it can avoid operator induced equipment causalities and their associated cost. The act of keeping our hand on a control until verifying the commanded action and pausing to evaluate the unexpected, are signs of an accomplished pilot. So too are those who walk carefully and with purpose around an aircraft and whenever they touch it, do so with a light hand. It’s a mindset that doesn’t just apply to doors.
A misplaced step or push can easily break a fairing or dent a panel. Use the glareshield or door trim as a handgrip to reposition your seat and the fabric will eventually tear or the plastic will crack. Lean the fueling nozzle against the rim of the fill port and over time the metal will work harden and be susceptible to fracture. Overzealously clean the windows and you can score a haze of rub marks into the surface. If pilots are insufficiently sensitive to the delicate nature of airplanes, those who are not pilots, are understandably oblivious. For this reason, a policy of look-but-don’t-touch should be in place, even for passengers until proper instruction has been provided. Neither pilot nor passenger should take for granted how to climb aboard, use a seatbelt, adjust a seat, or operate a door simply because they bear superficial similarity to something encountered in other contexts. Clear and firm explanation of what should, and also what should not, be done is a responsibility that mustn’t be neglected because of concern for either the press of the schedule or the ego of the passenger. Professionals on both side of the conversation will appreciate pilot attentiveness in such detail, and you may save yourself a lot of nuisance repairs.