Tips for a proficient preflight
The preflight is a ritual, a "detailed method of procedure faithfully or regularly followed," as The American Heritage Dictionary of the English Language defines it. After you've preflighted the same airplane over and over, it becomes an habitual ritual performed without the aid of the multi-page, step-by-step process detailed in the airplane manual or pilot's operating handbook.
It also can become a meaningless ritual. That's a potential consequence of routinely performing the preflight inspection and always ending with a clean scorecard. We may examine the airplane thoroughly, but over time we allow ourselves to be conditioned to expect the same result -- no problems observed. Armed with a foregone conclusion, we go through the motions of an inspection but aren't really engaged in the action. We may not comprehend much of what we're seeing, or our concentration is diverted to something else and we miss a problem.
It's a familiar scenario: Arrive at the airport behind schedule, and rush through the preparations trying to make up time. The frenzied pace of the preflight inspection is reminiscent of the way characters moved in silent films. The airplane must be preflighted, but the inspection is conducted more out of habit than real conviction. A quick circuit around the airplane, a tug on the flight control surfaces, a look at the engine oil level, and it's done. She's ready to fly.
That accelerated, pro forma approach to a preflight isn't desirable, but it's understandable. Light airplanes are relatively simple machines that receive regular, periodic inspections and maintenance, so for the most part they are reliable. When a mechanical or electrical problem does occur, generally it is known before the preflight inspection, or else it escapes even the most discerning inspection -- a failed vacuum pump or bad magneto, for example.
Most of the stuff that works the hardest on a powered airplane, including the engine and the accessories attached to it, hide under the cowl, where they are difficult if not impossible to examine thoroughly on a preflight inspection. If the side cowlings open wide we can check for such things as loose wires and leaking oil and other fluids, but we can't measure piston ring wear, magneto timing, and other potentially major problems.
A few moving parts on the exterior are visible to us, including the propeller, flight control surfaces, and wheels and tires. Given that convenient access, these high-wear components ought to be examined thoroughly.
Other than checking for bald tires, thin brake pads, gouges in the propeller, low oil level, and contaminated fuel, why spend the time on an extensive preflight inspection if it's likely nothing unusual will be found? Simply because there is always the chance that you will identify some problem that, if it went undetected, could ruin your day.
Twice I found a bird's nest in my Cessna Skyhawk. One was sitting on top of the engine; the other was buried deep in the tailcone. Either one could have led to problems in flight if I had not discovered and removed them during the preflight inspection.
Preflight inspections are important to renter-pilots and owner-pilots for different reasons. A rental is flown frequently by many people of widely varying skill, judgment, and respect for fellow pilots. The renter-pilot has no way of knowing how the airplane was treated by previous renters, or in what condition they left the airplane (see "Preflight Precision," November 2004 AOPA Flight Training).
Did the previous renters encounter any problems on their flights and, if so, did they squawk them -- write them down or, better yet, notify the school, fixed-base operator, or mechanic? Under those circumstances a thorough preflight based on the manufacturer's guide is good insurance.
The owner-pilot has a great advantage in always knowing who flies the airplane and how, where and how it is maintained, and where it is stored. That knowledge and control instill confidence in the day-to-day condition of the airplane, and that in turn changes the nature of the preflight inspection. It becomes a "howgozit," a trend-monitoring exercise, instead of the detective-like search for clues practiced by the renter-pilot.
For example, I once owned and flew a Piper with a right stabilator trim tab that had a bit of play in it compared to the left tab. This developed over time, and I was able to monitor the wear in the piano hinge, which was the source of the sloppiness. My preflight inspections always included a careful check of both trim tabs, and at some point I determined that it was time to replace the right hinge. The renter-pilot would not have the advantage of such trend monitoring and therefore may be faced with making an on-the-spot decision about whether the airplane is safe to fly.
The owner-pilot has another big advantage in being able to do an extensive preflight in advance of a planned flight. Spending an hour or so with the airplane the day before the trip is a great way to lessen the pressure and anxiety on the day of departure. It also allows time to have a problem corrected and still make the flight.
Two things that both renters and owners can do to reduce the potential for problems is to conclude the preflight inspection with a "last look" and conduct a post-flight inspection.
A last look is just what it says. After finishing the standard preflight inspection and loading the airplane, step back, take a deep breath, and change your focus to allow for a big-picture view of the airplane. It's amazing what conscientious pilots have forgotten in the rush to get going, even though they've done a preflight -- chocks snugging up against a main landing gear tire; a pitot tube cover still in place with a long, hanging streamer; and even a tow bar attached to the nosewheel. A good last look will save you from joining that hapless club.
Finally, a quick post-flight inspection can make all the difference in encountering or avoiding problems on your next flight. Before shutting down check to see that suction, the electrical system (ammeter/voltage indications), and the mags are performing properly. After shutting down do a quick walkaround to look at the tires and brakes and the condition of the propeller.
If all check out, chances are that your next preflight will go just as you hope and expect it to -- routinely.
Mark Twombly is a writer and editor who has been flying since 1968. He is a commercial pilot with instrument and multiengine ratings and co-owner of a Piper Aztec.
Related Articles
