Once he’s out at the airplane, the pilot begins a preflight inspection. Following a checklist supplied by the airplane manufacturer and contained in the airplane’s Information Manual, he first sits in the cockpit and checks the major electrical systems. He turns on the master electric switch, which turns on the juice to the instrument panel and the avionics.
In almost every case, the cockpit check will turn up no problems. So, with a checklist in hand to remind him of all the details, the pilot begins an exterior inspection. Often flight schools transcribe the checklist from the Information Manual onto a laminated card to make the checklist easier to handle and less vulnerable to fuel and oil spills.
By the Book
Avionic* it a word created just
for aviation. It’s a combination of two words-"aviation" and “electronics*—and it refers to the navigational equipment and two-way voice radios a pilot uses, as well as to the new generation of high-technology devices.
Birds seem to have a fascination with airplanes. I’ve seen bird nests in wheel wells where retractable landing gear arc stored during flight, and I’ve seen them in engine compartments. I even saw a bird make a respectable start on a nest near the horizontal stabilizer of a twin-engine Piper Seminole, and she did it in the 45 minutes between two flights. Bird nests are perhaps the most common foreign object you’ll find during preflight inspections.
For the most part, the preflight inspection is meant to make sure the mechanics have not made any serious mistakes and that other pilots who flew the airplane recently didn’t cause any damage. It doesn’t go much deeper than a surface inspection, but careful pilots can turn up some significant defects in time to get them corrected on the ground.
Depending on the model of airplane, the pattern and details of the exterior preflight will vary. In a small Cessna, for example, the preflight starts at the back of the left wing and progresses clockwise around the airplane.
After checking that the ailerons move easily, the pilot checks the wings’ leading edges. Here, he looks for any signs that the plane might have bumped into something while moving around the airport. It’s not uncommon to find small dents, called “hangar rash,” that come from being moved around during maintenance, but the leading edges should be relatively smooth.
The most important check of the left wing of most small planes is the “stall warning horn.” In a Cessna, this is a simple hole in the wing’s skin that must not be blocked by insects or litter. In other planes, it might be a simple switch that must be free to move easily.
Both of these devices trigger an audible warning to the pilot during flight if he is getting close to the critical angle of attack that could result in a stall (discussed earlier).
Also on the left wing is the fuel tank. The pilot will step up onto the wing for close inspection. Not only does he want to make sure the fuel cap is securely fastened, but he also has to make a careful check of how much fuel is in each tank. It isn’t enough to rely on the fuel gauge in the cockpit to make sure there’s enough fuel to finish the flight safely. The risk is simply too high to leave that up to a sometimes-faulty gauge. So airplane manufacturers provide a fuel stick—a graduated metal or wood stick that a pilot dips into the tank until it hits bottom. When it’s pulled out, the pilot can see the line of liquid and check it against markings that indicate how many gallons are in the tank.
It’s not just pilots of small airplanes that have to perform preflight checks. The pilots of jetliners also do a "walk around," usually armed with a flashlight that lets them peer into the holes and recesses of a modem jetliner. It’s more than simply "kicking the tires and lighting the fires.* Professional pilots know they can’t rely solely on mechanics to keep the airplane safe. Everybody, even aidine captains, have to play a role.
The pilot then checks the fuel in a second way. A small valve located on the underside of the wing allows the pilot to pour some raw fuel from the tank into a clear plastic sampling cup. Any particles of dirt or globules of water will be easy to see.
Finally, before moving on, the pilot unhooks the tie-down ropes or chains and inspects the tires and brakes.