The preflight inspection
8 min readLesson 9 of 59
- Explain why every flight starts with a preflight
- Check fuel for the right grade and contamination
- Know the key items on a walkaround
The pilot in command is responsible for determining that the aircraft is in a condition for safe flight (14 CFR 91.7). The preflight inspection is how you do that. Always use the checklist from your airplane's POH; this lesson explains what you're looking for and why.
In the cabin
- Required documents on board (Unit 6 covers which ones).
- Master switch on: check fuel gauges, flap operation, lights. Then master off.
- Magnetos off and the key out (or on the dash) so the propeller can't fire.
Fuel
Look in the tanks to see the actual fuel level. Gauges on light airplanes are only required to be accurate when empty, so never trust them alone. Then sump every drain with a fuel tester:
- Color: 100LL avgas is blue. Jet fuel is clear or straw-colored and will destroy a piston engine.
- Water: water is heavier than fuel and sinks to the bottom of the tester as a bead or bubble. Keep draining until it's gone.
- Debris: no dirt, rust or particles.
Engine
Check the oil level against the POH minimum, look for leaks, loose wires, bird nests in the cowling and a secure exhaust. Inspect the propeller for nicks; even small ones can grow into cracks.
The rest of the walkaround
- Control surfaces move freely, hinges and bolts secure, no damage.
- Tires properly inflated, no cord showing; brakes not leaking.
- Pitot tube cover off and pitot and static ports clear.
- Tie-downs, chocks and control locks removed. (Taking off with the control lock in has killed pilots.)
- Stall warning works and lights work.
Key takeaways
- The PIC must determine the airplane is airworthy before every flight (91.7).
- Sump every drain: blue 100LL, no water beads, no debris.
- Always check fuel visually and remove control locks, tie-downs and pitot covers.
What the examiner may ask
Practice answering out loud before you open each answer.
How do you check for water in the fuel?
Why visually check the fuel tanks?
What do you do if you find something questionable on preflight?
Common mistakes
- Rushing the preflight because the airplane 'flew fine last time'.
- Forgetting to remove the control lock or pitot cover.
- Trusting the fuel gauges instead of looking in the tanks.
Read it in the FAA sources
Go deeper on the site
Lesson check
Get every question right to complete the lesson. Take your time; wrong answers explain why.
Something wrong or out of date? Report an error