Preflight (Part 2): The Real Square One

I find it curious that one critical precept of flight — one that we are all taught at the start of our training — is rarely again explored in the same level of detail, but so vital to our survival. I am referring here to the preflight inspection of our aircraft.

The laws of physics don’t change, and neither do the basics of controlling an aircraft. Regardless of whether our understanding of either is the result of a thirst for knowledge, or the minimums dictated by a flight review, most of us must revisit at least some of these basic principles, from time to time. But while your BFR may cover Part 61, Part 91, airspace, charts, the A/FD, weight and balance, decision making, weather, etc. — what about that aircraft, while it’s still on the ground? What about reviewing one of the most important precursors to safe flight — the thorough examination of an aircraft to find potential problems before they find you? Are there any regulatory measures in place designed to prevent apathy from overcoming the vigilant preflight?

The regulations say that, as pilot in command, we’re “directly responsible“; we’re the “final authority“. BUT there is nothing in CFR Title 14, specifically regarding preflights, in Parts 1, 61, or 91 (except by catch-all implication, 91.3 of course). The Aeronautical Information Manual, in Chapter 5, AIR TRAFFIC PROCEDURES, has Section 1: PREFLIGHT … which refers to briefing and filing a flight plan. Moving further around the bush, if you consult the new (1999) Aviation Instructor’s Handbook, FAA-H-8083-9, (which every instructor has used to study for the Fundamentals Of Instruction knowledge test) you will find Chapter 9, titled “Techniques of Flight Instruction.” Within that chapter is a section called “APATHY DUE TO INADEQUATE INSTRUCTION” and another on “AERONAUTICAL DECISION MAKING“… but that’s the closest I’ve managed to get to finding an FAA document intent on making sure vigilant preflight procedure is reinforced and then properly maintained.

I mean, come on! We only gradually learn the nuances of aviation over time, and after our introduction, not a word do we hear about this most critical first step, ever again! Sure, there are some gifted folks among us with natural affinities for sensing a disruption in the force, if they so much as walk up to an ailing airplane, but what about the rest of us … or the mechanically inept … like me?

In my case, when I first started flying, I had to ask for it. I remember my CFI shrugging his shoulders and humoring me when I said that I wanted him to watch me. (“What, Jeff? Again?“) Early in my helicopter flight training, I had the privilege of flying with a CFI who was also an A&P, and I happily spent the money for a couple of hours of his time so that I could get a more detailed introduction to all the strange and new attachments and structures on which my life would depend. I don’t think we even got off the ground that first time.

Checklists: I’ve never failed to impress people with my mastery of the obvious, and I’ll ask in advance for your forbearance on this one: checklists. Ya can’t see da show witout a program, folks, and whether that’s only a few dog-eared pages of a POH, or a neatly laminated edition tucked under a seat belt, the preflight starts where the checklist should be: inside the aircraft. Documents, switches, indicators, fuel shutoff valve, seat locks (also known on Cessnas as “lawyer locks“) and flap operation — all these may change as you fly different aircraft, but appreciation of their importance should stick with you. (You may be intimately familiar with the aircraft you fly, and in such cases of course a checklist might safely graduate above the level of the read-it-out-loud, finger-on-the-page, line-by-line “do list” that we should all be dutifully wading through on our first few dozen flights. But we’re human; we forget stuff, okay?) So lets get on with it…

Fuselage: Once outside the cockpit, you’ll be looking at the fuselage for wrinkles (literally), loose rivets, any deformations in control surfaces, and even simple things like clean windows. You’ll want to be sure that the pitot-static openings are, well, open. You’ll look at the wing-struts (probably missing on your low-wing Piper, though) the landing gear, tires (and be sure to roll the aircraft a few inches so you can check for any worn spots all around the tires), and the brakes.

Control surfaces: Are the control locks out? Do all control surfaces move freely without any binding, clicking, or grating, and are all hinges and hinge pins — and the safety wire or screw that holds them in place — correctly installed? Be especially wary of anything that looks like a crack near a hinge. Be certain that travel-limiting bolts for the rudder meet squarely (if they don’t, the rudder may lock in a deflected position). Trim tabs should not be movable at the tab itself. With flaps, watch out for bent control rods, mounting brackets, hinges, and any trailing edge cracks. Make sure counterweights are present and accounted for, and that all control cables are attached and fastened properly.

Hardware: This is a topic unto itself. You should learn what properly safetied nuts and bolts are supposed to look like. Learn to recognize all locations that require them, whether in the form of cotter pins, safety wire, torque stripes, locknuts, etc.

Fuel: If you don’t already have one, get yourself a calibrated fuel tester. Take a sample from the strainer before every flight. Look at it carefully; don’t just let it run onto the ramp. It may look like a light blue stream squirting out of the nose sump, but you won’t see entrained water unless you collect some in a clean fuel tester. (Granted, with some airplanes you might need the reach of an orangutan to do this.) Of course, check the color: blue for 100LL, clear or amber for jet fuel or autogas. (Speaking for myself, I’ve never even seen the proverbial red 80 octane, nor 100 green.) Always check that your fuel caps are secure (and that they’ve been on since the last rainstorm) and also that fuel vents are unobstructed. By the way, if you’ve so far been fortunate enough not to have ever had even slightly contaminated fuel, it would be a useful exercise some day (maybe when the weather is frightful and the ducks are walking) to take a little 100LL and mix it in with some water in a clear jar. Shake it up a bit, then a lot. See for yourself what entrained and settled water actually looks like.

Oil: Just as the eyes are a window into the human body, the condition (and correct quantity) of that lubricating fluid can both divulge (and foretell) your engine’s health. The best way to measure it is with a dipstick of course — but make sure the dipstick is clean, and wiped on a clean cloth, to better display impurities (such as, heaven forbid, metal particles). This practice also eliminates the optimistic readings that natural adhesion always permits.

Gear: Proper tire inflation is easy to eyeball, and likewise worn spots, bulges, brake line leaks, wheel rim cracks, and proper strut inflation (where applicable) are also easy to spot. Obviously, you’ll want to check that rims are on, brake pads are the proper thickness, and that there are no obvious bends in the gear that weren’t designed to be there.

Engine and propeller: Be sure the ignition is off, and never place any part of your body inside the propeller arc. Check leading edges for nicks, cracks, or dents, and if you see anything deeper than about two millimeters, stop right there and go see the crew chief or your A&P. Look for spinner cracks, especially the bolt holes and back plate. The alternator belt shouldn’t have more than about a half-inch of give to it. Other things to look for are loose baffles, obstructions on the carburetor air cleaner. Obviously, inspect all openings for any would-be tenants.

BOTTOM LINE: Yes, know the proper walk-around sequence. Know what to look for. But beyond that, stay focused. And remain suspicious. I don’t mean to sound like Yoda here, but see with your mind what your eyes are telling you. It’s too easy to get un-focused, hurried, or distracted. They talk about a sterile cockpit. The same goes for during the preflight. Buy some time — that of your instructor, and better still, any slightly avuncular aircraft mechanic. They’ll probably be thrilled that you’re even interested.