Flight Instructors will always stress the
Preflight - and for good reasons. All
pilots should do a thorough preflight, although there are a few more cocky pilots who believe they can glance at the
airplane, remove the
chocks and
cowl plugs and start 'er up. Doing a proper preflight is also a part of every student pilot's check ride. The Preflight is always the responsibility of the Pilot-in-command. Not so coincidentally, anything that goes wrong with the plane is usually his or her responsibility also.
A preflight can catch things that could easily
kill you in
flight or in an attempt to take flight. There have been quite a few
NTSB reports dealing with cowl plugs, tools in the cowl, and other
careless mistakes. Completing the preflight inspection can save lives.
After being a
student pilot for a while, I got used to running through the preflight
checklist. The point is to get
proficient and efficient, but not careless. A basic checklist for a preflight on a small aircraft (a
Cessna 172 in this example, but it works for most of it's kind) is as follows:
- Check your Required Documents:
- Set the Parking Brake - To keep the plane from moving, possibly rolling over you.
- Check the Fire Extinguisher is Charged - Fires happen.
- Record the time on the Hobbs and Tachometer - To record length of flight.
- Remove the Control Wheel Lock - So you can move the controls; make sure they move freely.
- Ensure Ignition Switch is at OFF - If this is on, the magnetos can be hot. When you turn the prop, it could easily start and take your hands off... or more.
- Ensure Avionics Switch is OFF - If everything is on when you flip on the master, you might blow a fuse
- Master Switch ON - This turns on power to all electronics.
- Put Flaps at 10 - 30° - When flaps are down you can check them easier.
- Avionics Power Switch ON
- Listen for Avionics Cooling Fan - If the fan isn't on, your equipment will overheat in flight and fail.
- Avionics Power Switch OFF - No need to keep them running.
- Check Low-Vacuum Light is ON - Your plane shouldn't be making a vacuum yet, it's not moving.
- Check Fuel Quantity Indicators - Not foolproof, but helps to double check everything. If they're showing full when your tanks are empty, that's a problem.
- Check Exterior Lighting (Anti-Collision lights, nav, etc.) - You want these to work
- Master Switch OFF - Keep the Hobbs meter from running during your check.
- Fuel Selector Value set to BOTH - Evenly takes fuel from both tanks, this way.
- Static Pressure Alternate Source Value pushed OFF - You don't need an alternate source, your primary should be good.
- Baggage Door LATCHED and LOCKED - To keep your goodies from leaving you midflight.
Now for the Exterior:
At the Empennage:
- If Necessary, remove the Rudder Gust Lock - Keeps wind from moving your rudder when parked. You want to be able to move it.
- If Necessary, remove the Tail Tie Down - You don't want your plane tied to the pavement.
- Check Tail Control Surfaces for moveability - If these don't move, you can't control the pitch of the plane.
At the Right Wing:
- Check (now extended) Flap - look for bad bends and dings that could effect performance
- Check Aileron - Same check as flap
- Remove Wing Tie Down
- Check Main Wheel, Tire and Brake - Not flat? No brake fluid leaking?
- Drain Fuel Sump, & Check for Water / Debris - You dispense a little fuel into a cup, and look for water bubbles or debris. Both of these can effect the performance greatly, and could even cause stalls.
- Visually Check Fuel Quantity in Tank - Meters aren't fool proof
- ReSecure the Fuel Filler Cap Watching fuel streaming from your wing, in-flight, isn't a happy sight.
Moving to the Nose:
- Check Engine Oil Quantity is in acceptable range
- Resecure the Oil Filler Cap
- Drain the Fuel Strainer and Check Visually for Water or Debris - Again, water in the fuel is bad.
- Close the Oil Access Door
- Drain the Fuel Selector Drain - Once more looking for water/debris in another section of the fuel system.
- Walk to the front and check the propeller leading edge for nicks and cracks - These can cause problems in flight.
- Check spinner to be on securely - You don't want the spinner to fly off at 2600 RPMs...
- Check Engine Cooling Air Inlets are clear of animals, birds (yes, this is quite common in cowlings... nice and warm for the birdies), or tools left by a mechanic. ***Starting engine with objects here can cause serious damage
- Check the Carburetor Air Filter screen is relatively unobstructed - You don't want to block airflow to the carb.
- Check the Nose Wheel; Tire for pressure, and strut is showing some strut. - If the strut is totally down, it means there's no pressure, thus no cushion when you land.
- Remove the nose tie down if necessary
- Check the Static Source opening is clear - This works with vacuum instruments, and in calculating airspeed. It should always be clear.
Moving to the left wing of your aircraft:
- Visually check the fuel quantity in the left wing tank. - Again, gauges can lie or fail.
- Resecure the fuel filler cap
- Remove the Pitot Tube cover and inspect pitot tube is clear. - This is also used in calculating altitude and airspeed. With it plugged, it can cause you many problems.
- Check Fuel Tank Vent Opening
- Check Stall Warning Opening - If this is blocked, you won't hear the warning buzzer when you're about to stall. Bad.
- Test Stall Warning by sucking in over opening through shirt, or omit if you prefer. - This simulates vacuum over wing created by stall. You should hear the buzzer.
- Remove the wing tie down, if necessary
- Check the Main Wheel Tire
- Drain the fuel sump and check for water and debris
Move the the Left Wing Trailing Edge:
- Check the Aileron and Flap
- Feel safe to enter the aircraft and begin the Engine Start Checklist. :o)
At this point, you're airplane is basically safe to fly - as far as a pilot could determine. This doesn't mean things can break or fail anyways, but it can catch quite a few things before the flight occurs. You can always delay a flight if you find something broken on the ground, but once you're in the air it can become a competely different story. Takeoffs are optional, landings are mandantory.
Sources:
- Personal Knowledge and from my time at the US Air Force Auxiliary Flight Academy.