# Snap! Crackle! Pop!

…And other sounds an Airplane SHOULDN’T MAKE! When you think about it, most airplanes are incredible pieces of formed metal. There are thousands of pieces of aluminum, other metals and composites involved in the construction of the plane. Held in place with rivets, welds, and fasteners such as screws and bolts, these pieces of metal work together to allow us to fly through the air.

STILL, some of the pieces are designed to handle a specific, set load — if you exceed that load, you can cause problems. We’ll take the step on a friend’s Bonanza as a good example. If you looked at this step, you would probably think you could use it to jack up the plane — it looks that robust. Chromed, solid, this step could be a kickstand, and from pictures you’ve seen, it even looks like it could stand up to the forces of a gear up landing.

SO YOU THOUGHT. The step is very robust, and it is bolted into a bulkhead, which hides inside the skin of the plane. You could probably jack up the plane with the step, but you shouldn’t, because the step isn’t designed for that purpose! The step is designed for just that — stepping. Not jumping, not carrying heavy baggage, stepping.

CONSIDER THE PHYSICS INVOLVED. If you ‘step’ on the step with normal force, the mass of your body will be imparted on the step. Since you do so with normal force (not a jump), your acceleration is minimal. In terms of physics, Force equals Mass times Acceleration. The step is designed for this force, and works just fine.

NOW LETS JUMP A BIT. You’re in a hurry to get out of the plane, and you leap a foot from the wing to the step. You have the same mass, but you now have more velocity due to the distance. This force is MOMEMTUM (Mass x Velocity, or mv). While it is only a difference of a foot, that equates to a SIGNIFICANT difference in the force on the step!

(No, this isn’t the same for 5 year olds — remember, aircraft were designed with normal adults in mind, adults that were assumed to weigh 170 pounds …)

In the case of our friend’s Bonanza, he noticed that every time he stepped on his step, (and he did step, he didn’t jump), his plane made noises. The plane made those ‘snap, crackle and pop‘ noises in fact. Being a good owner, my friend took his plane to a qualified repair facility, and got the bad news.

We inspected your plane, and found that the bulkhead that the step is secured to is severely cracked,’ the shop manager told him. ‘We have to replace the bulkhead, as there is no approved way to repair it.

OUCH! The plane had to be supported properly, and the bulkhead’s rivets were drilled out. In case you don’t know, this bulkhead runs the entire circumference around the inside of the fuselage. It had to be carefully removed, and then a new one installed and correctly jigged and riveted into place. The repair took a bunch of shop hours to complete — thousands of dollars later, the plane was as good as new.

THE SHOP DID THE RIGHT THING, and so can you. REMEMBER:

• the step is there to assist you as you get in and out of the plane.
• steps are designed to be stepped on, NOT JUMPED ON
• if your airplane makes sounds like something that is cracked or rubbing, the chances are good that something is cracked or rubbing. Have your mechanic check it out before it gets worse!

HOW YOU TREAT YOUR PLANE will have a direct effect on how long it operates without the need for repairs. If you treat your plane with respect, it will provide you with years of fairly trouble-free operation. If you treat your plane roughly, you should expect the mechanical bills that result. Knowing how to get into and out of our planes properly, and instructing our guests to do the same, we can avoid causing expensive and unnecessary damage … and that means more money for fuel!