The Pilot's Lounge #75: Preflight? Who Cares?

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Recent AVweb columns have brought the question to the fore: Should a pilot perform a detailed pre-flight inspection, or is there such a thing as too much information? AVweb's Rick Durden has a thorough conversation about it this month in The Pilot's Lounge.

The Pilot's Lounge

I was in the pilot's lounge, here at the virtual airport, doing my shallow breathing exercises, when I found myself eavesdropping on some training one of the instructors was giving to a primary student. The instructor was going on and on about the importance of the preflight inspection as well as all of the possible horribles that could occur to the hapless student if he failed to check everything on the airplane. The student was starting to get pale as the instructor got into wings folding and propellers flinging blades, so much so that I began to wonder whether this instructor would manage to chase off yet another student pilot and then have the chance to complain about how there just aren't any people who really want to learn to fly.

A bit later, I heard Sandy -- one of our resident airline pilots and a Citabria owner -- pull the instructor aside and suggest to him that he approach the preflight from a more positive standpoint, that of making sure things are working, rather than from his very negative point of view. She reminded him gently that new students are fully aware that they can kill themselves in airplanes. After all, each person who walks in the door expressing the desire to fly is much braver than the average member of our society because he or she has spent a lifetime being inundated by our media happily extolling the dangers of little airplanes.

While Sandy was talking with the CFI, I got to thinking about her philosophy of a preflight versus that of the negative CFI, and I was reminded of Michael Maya Charles' recent column about all of the stuff he had to learn while going through MD-11 school. He allowed as how a fair proportion of it was meaningless rote memorization of trivia that every pilot from the Montgolfiers on has promptly dumped from his or her brain once a checkride was complete because it would never be used in actual operations. After his column appeared, one of his readers commented negatively on it by referring to the column I had written about the legendary test pilot, Al White, and the very long preflight I had done with Al on a Cessna 402 some years ago. The commentator pointed out that Al had wanted to know all that he could about the airplane on the preflight and therefore there really wasn't anything that a pilot should not consider important when learning about an airplane. The seeming inconsistencies expressed in the columns and the thoughtful comments by the reader -- as well as overhearing the CFI teaching a primary student -- caused me to try and find out if there were an answer to the historic question of how much and what information a pilot should have about the aircraft when it comes to a preflight, and how to actually perform one successfully.

Learn Things You Can Change, Accept Things You Cannot

When I reread Michael Maya Charles' comments and thought about Al White's approach to a preflight inspection, I realized that there were no inconsistencies in the way those two operated aircraft. Both are consummate, experienced professionals who take an extremely pragmatic approach to the subject of flight. Each wants to know as much information about an aircraft as possible so long as that information is directly related to being able to get it from one place to another and having it arrive in as attractive a form as it departed, all the while maintaining a reasonable heart rate. If there is information that a pilot can use in that process, it's valuable; if the information is about something the pilot cannot affect through his or her actions either before or in flight, it is surplus and rightfully assigned to the trivia pigeonhole.

When I spent an hour doing the preflight of a 402 with Al White, his questions regarding specific details always had to do with what he could learn and observe on the preflight that would allow him to make a decision as to whether to accept the airplane for flight. He wanted to know such things as how the ailerons were attached to the airframe and how to visually inspect that attachment, or how the hinges and actuators should look if everything were correct and in order. Therefore, if things did not match that mental picture, he would either refuse to fly the machine or get a mechanic involved who knew the airplane. Interestingly, when he had found something that caused him to be unwilling to fly the airplane, he would remain in that mode until the mechanic demonstrated to his satisfaction that what he observed was within normal, acceptable tolerances or that the problem had been fixed. He wasn't interested in the pounds of torque for the bolts that held the hinges, the type of aluminum alloy used for the aileron skins nor the specific number of degrees of aileron deflection, because those were things he could not inspect on a preflight and, he recognized, he had to rely on the people who built the airplane and the mechanics who had worked on it. He certainly wasn't going to tear it down to determine whether all the parts were in tolerance and were assembled correctly.

In reading Al White's book, I was impressed by the number of things that went wrong in flight that he could correct because he knew the systems extremely well and knew what he could correct by taking action in flight. However, he didn't bother with such a detailed knowledge of systems that he could not affect should they fail in flight beyond knowing how to shut them off, or disable them, if possible, so as to stop them from adversely affecting the flight.

As I was considering all of this, I remained troubled by a recent experience in which I had overlooked what could have been a significant problem on a preflight. I'd been flying a Cessna 206 every day for about a week and was about to check out another pilot in the airplane. He did the preflight and found a crack that went around half the circumference of an exhaust pipe. I had missed it for the entire week, as I doubt it had suddenly appeared on the last flight. He had done something I normally do, but had been neglecting: He had taken hold of the exhaust pipe and wiggled it.

With the above thoughts swirling around, I spent some time talking with folks I respect who frequent the Pilot's Lounge. While four pilots can often express five opinions as each hopes that someone else is going to pick up the check at lunch, I did get an interesting consensus about a number of things regarding how to perform a preflight inspection. These ideas will provide a good chance of identifying when there is something wrong with the airplane, prior to having it make loud, disturbing noises in flight.

In listening to my betters, doing a lot of reading on the subject -- including accident reports -- and hopefully learning from my own mistakes over the years, I've decided that a successful preflight is a function of whether the pilot applies a single-minded focus on the airplane itself during the entire process.

Without Distraction

It begins as you open the hangar door or are walking across the apron to where the airplane is tied down. That moment, when you first see that flying machine, that amazing creature of flight, is when it should become your entire world. You look at the aircraft. All of it. For the time being, nothing else need exist for you but that aircraft. You think about how it should look and focus on matching that idealized vision with what you are actually seeing. One friend of mine refers to the process of concentrating completely on the airplane during a preflight as a Zen sort of experience; you feel or become the airplane, reaching out to it mentally to be aware of the structure of its existence. Another friend, an airline captain I deeply respect, used a different label for the same process of total concentration while preflighting; that of old-fashioned Catholic/ Jewish/ Midwestern guilt and paranoia: You try to look into every little nook and cranny, because you know something is wrong and you just have to find it. I'd like to consider the preflight a combination of the best portions of both of those approaches and try to avoid labels. I just make certain that I concentrate on the airplane to the exclusion of anything else.

So, what do we include on the preflight itself? The POH or the Owner's Manual for the airplane provides guidance but, because it is not a "how to fly" book, it does not presume to tell everything. The private pilot manuals every one of us studied "way back when" provide even more guidance; as do our primary flight instructors and other pilots we've spoken with over time. I suspect that most pilots have had some scares due to missing something on a preflight, so they have modified theirs accordingly. Each airplane has its special areas that must be examined, such as challenges involved with actually sampling the fuel for some airplanes, or checking the level of the hydraulic fluid in others. Such specialized systems mean that first you have to look at the handbook for the airplane and read what the manufacturer recommends doing on the preflight, learning how to go about finding those fluid reservoirs and little eccentricities. After that, it's a matter of remembering the general things you learned long ago, to check to see that all fuel and oil filler caps are attached, and that no one has swiped a wing, that sort of thing.

No matter what is appropriate to include on the preflight of a particular type of airplane, the operant concept is focus, to point that intellect of yours at the task of insuring your ride is going to get you there and back again. How many accidents have occurred because the pilot got interrupted at exactly the wrong point on the preflight? Is it fate that pilots got distracted right then and missed something that would have been obvious -- a missing oil filler cap or that the airplane had just come out of the paint shop and someone hooked up the ailerons backwards? (Yes, that has happened more times than is comfortable to consider, and a huge proportion of pilots who got those airplanes into the air died trying to fly them.) To be fair to yourself and your passengers try to set things up so that you can do a preflight without distractions. Randy Sohn, who flies dozens of different types of airplanes with the Commemorative Air Force, has a practice of insisting on several minutes with the airplane he is to fly, without any interruptions. It helps him make sure the airplane is ready to go, and recall the speeds and systems for the airplane. Then he is mentally ready for the challenges and any ill behavior it might demonstrate. If it's good enough for the guy who successfully flew the CAF's B-29 out of the boneyard in California all the way to south Texas, nonstop, to start its restoration process, then I figure the "fully focused on the airplane from the moment the pilot approaches it" concept is the one I should follow.

The First, Long Look

On that first look at the airplane, take in the big picture. Is anything hanging from it? Is anything dripping or is there any indication that something has been dripping? Are all the antennae sticking out from the appropriate spots? Is the airplane sitting level? If not, why not? How do the wheels look, the landing gear legs/struts? During that first good look, from a distance, you are trying to spot those things that you might overlook up close. For example, if the airplane is not sitting level, both fore and aft and side to side, it may not be able to hold its full rated quantity of fuel. That's especially important if it has wings with little dihedral and fairly large fuel tanks. If it was not fueled while sitting level, there is a chance it is not really full of fuel, which could bite you in a few hours. So check. If the ramp is level and the airplane isn't, find out why. It may just be a shock strut on one main gear that is not fully inflated, but it may also be something serious such as broken structure. Really look at the outside of the airplane. I keep thinking of the two pilots who set off to steal a light twin about ten years ago. They ran toward the airplane but didn't notice that the flight controls had been removed. Yes, they went off the end of the runway at very high speed, firmly on the ground. Yes, they were seriously injured.

Then, look inside for the aircraft documents and to get the flaps extended (if that is your practice), remove the control wheel lock, get the fuel sampler cup and take a general look, and I mean look, at the interior. Is a seat crooked? Is it off the track or is it broken? Has someone stolen a radio?

Once outside, do what you've been taught, and do it in an orderly fashion. If you do get distracted (hey, life isn't perfect), the risk is skipping something in that general area, so I'd suggest going back two or three steps and start over, not from the beginning, just back maybe a quarter of the way around the airplane.

Be prepared to get dirty. I am not convinced it is physically possible to preflight a piston engine airplane without getting dirty unless you wear gloves. Maybe it's a good idea to toss a pair of gloves into your flight bag for the days you have to wear a suit because you are flying to a meeting. You may even want to get one of those silly-looking, one-piece flight suits or coveralls that you can slide on over your clothes for days where you have to dress up for a flight. Getting dirty ties into the preflight where I slipped up: One has to grab hold of things to make sure they are secure. Grab onto those tailpipes and give them a little shake. If there is a crack, move it enough to spot the crack. Tailpipes have been so badly cracked that they have fallen off in flight, leading to fires; the simple act of laying on of hands prior to launch probably would have identified the problem.

Plenty of Fluids

Do you have enough fuel and is it clean? It sounds pretty basic, but look inside the tank. Take samples from all of the drain points, every one. Do you know where all of the fuel quick-drains are located? It means getting under the airplane in most cases to get the fuel sampled. Some fuel tanks have more than one quick drain. That's because folks discovered surface tension sometimes prevents water flowing to the lowest point in the tank, especially if the airplane isn't sitting level. If you get water in a sample, be very suspicious. If it's a small amount from one quick drain and three or four subsequent samplings from that drain are without water (and you know it is fuel, not water), then things are probably OK. However, if the airplane has been parked out in the rain, or if it was just fueled, or if you get water in two or three samples or from more than one quick drain, stop everything until a mechanic has a look at the system. Get some professional help because airplane engines just don't appreciate being fed water. You may have a leaking fuel cap (which seems to be the most common source of water), or the fuel you just took on was contaminated (it happens), so get an A & P involved and assure yourself that all of the water is out of the system. It may require that the system be drained and purged. True, it will delay departure -- but a slug of water in the engine at the wrong moment may forever delay your arrival.

Make sure that you got the kind of fuel you want; even with all the designed-in safeguards, jet fuel still gets put in piston pounders. Often it happens because the pilot is distracted when the fuel truck appears and starts to load the airplane. The great Bob Hoover was misfueled a number of times in the days he was doing his airshow in the Aero Commander Shrike. I guess line personnel just figured that to get that kind of performance from an airplane it had to have jet fuel in it. More than once he was standing beside the airplane signing autographs when the misfueling took place. He was besieged by fans, one of those minor distractions that we mortals rarely face, but the point is that distractions are how the mistakes slip past us.

Catch all the fuel you drain and either pour it back into the tanks (if it and the sampler cup are clean) or put it into a dedicated container for fuel samples. It's being done at more and more airports as the potential for contamination of ground water from dumped fuel samples has proven to be greater than was realized in the past.

If you fly an airplane used for training, look down the rows of rivets on the wings and inbetween the landing gear to make sure they still line up, that the airplane hasn't been overstressed and broken a rib or other structure.

Make sure the fuel and oil caps are in place. If you fly an airplane that does not have the dipstick co-located with the oil filler cap, check the cap. Often you can see it from the cooling air intakes in the front of the cowling. If the oil cap is off, oil is going to come out of the engine amazingly quickly. It may warn you by appearing on the windshield, but on some airplanes it will simply be blown downward out of the bottom of the cowling. You may or may not get an oil temperature increase and drop in oil pressure before the engine seizes, so check before you go.

It Was Here Last Time ...

Are the antennas in place? It's kind of strange to be looking at the airplane and have that nagging feeling that something is wrong, and then realize that an antenna has departed. I owned a Cardinal that developed an appetite for ELT antennas. They made no noise on departure, so I didn't realize it until a subsequent preflight where I went through the "I think there's something missing here" sequence before figuring out that there was an empty space where the ELT antenna used to live.

Look for abrasion or tears on the underside of the horizontal stabilizer and elevator. It's a spot few people check and I'm surprised how many times I've found torn skin from a rock kicked up from the landing gear, especially on airplanes that go into fields that are not always maintained in the peak of condition, which includes paved runways.

Are the landing gear struts properly inflated? A flat strut is not just an inconvenience; it's a no-go item on most airplanes. A flat nose strut on a Cessna 310 means that the nose gear will retract, but then it will jam in the wheel well and you'll get to make a landing on the mains and stare at the pretty runway when the nose drops through during rollout.

Are the static sources open? Touch them. If the airplane has been washed and waxed there is a chance that the static source has been plugged.

Touch things. Move the controls through their full range of travel; feel if the brake lines are secure. That doesn't mean yank on things, but pull gently and see if things are attached well. How are the tires? Any large flat spots? Tread okay? Can you be sure you are going to land softly and smoothly enough for those tires?

How is the prop? Yes, treat it as if it will start when you touch it, but touch it and feel for nicks and its overall condition.

Untie the airplane and get the chocks out of the way. It's embarrassing to start up and realize that one or more tiedown ropes is still attached or that you didn't pull the chocks. We've all done it, and it's a symptom of distraction on the preflight. By the way, powering out over the chocks is not one of the wisest things you might do with an airplane. A twin based at my local airport did that, the chocks flipped up into the nose gear well and, as Murphy's law would have it, did just the right kind of damage to allow the gear to retract but not extend.

A good preflight does not have to take half a day. We use the airplanes because they cut down on travel time, we don't want to waste it doing an endless preflight. The secret is to devote one's full attention to the task so that you're less likely to miss something.

And, paranoid is good, too. There's nothing to motivate a preflight like the knowledge that the airplane has been tampered with and you have to find it. It does wonders for your level of concentration. With that as a thought, why not have your instructor do a little sabotage on the airplane the next time you do your flight review? It might be a valuable learning experience.

See you next month.


Want to read more from Rick Durden? Check out the rest of his columns.