The Complete Aircraft Preflight Inspection Checklist

THE PURPOSE OF PREFLIGHT INSPECTION

The preflight inspection is the pilot's first and most important safety check before every flight. FAR 91.7 states that the pilot in command is responsible for determining whether the aircraft is in condition for safe flight, and the preflight inspection is the primary means of fulfilling that responsibility. No aircraft should leave the ground without a thorough, systematic inspection.

REQUIRED DOCUMENTS: ARROW

Before beginning the physical walkaround, verify that all required documents are on board. The ARROW acronym covers everything required by FAR 91.203 and 91.9: • A — Airworthiness Certificate (must be displayed so it is legible to passengers) • R — Registration Certificate (must be current and on board) • R — Radio Station License (required for international flights only) • O — Operating Limitations (POH/AFM, placards, and markings) • W — Weight and Balance data (current for the specific aircraft)

REQUIRED INSPECTIONS: AV1ATE

Verify that the aircraft is current on all required inspections using the AV1ATE memory aid: • A — Annual inspection (within the preceding 12 calendar months, per FAR 91.409) • V — VOR check (within 30 days if the aircraft will be used for IFR, per FAR 91.171) • 1 — 100-hour inspection (if used for hire, per FAR 91.409) • A — Altimeter/pitot-static system check (within 24 calendar months for IFR, per FAR 91.411) • T — Transponder check (within 24 calendar months, per FAR 91.413) • E — ELT battery and inspection (per FAR 91.207)

COCKPIT PRE-INSPECTION

Begin inside the cockpit before going outside: • Master switch ON (to check fuel gauges, lights, and avionics — turn OFF before exiting) • Fuel quantity gauges: note the indicated fuel level and cross-reference with a visual check during the walkaround • Check that all circuit breakers are in • Check the hobbs meter and tachometer for upcoming maintenance • Remove the control lock if installed • Check that the magneto switch is OFF before approaching the propeller outside

EXTERIOR WALKAROUND

The walkaround follows a systematic path around the aircraft. Most POHs specify a specific starting point and direction. A typical flow for a high-wing single-engine aircraft (Cessna 172) follows:

LEFT SIDE OF FUSELAGE

• Inspect the fuselage skin for dents, cracks, or missing rivets • Check the baggage door (secure and latched) • Inspect the static port for obstructions (insects, tape, debris)

EMPENNAGE (TAIL SECTION)

• Horizontal stabilizer and elevator: check for damage, freedom of movement, and security of attachment • Elevator trim tab: verify condition and security • Vertical stabilizer and rudder: check for damage and freedom of movement • Tail tie-down: remove if attached • Rotating beacon and navigation lights: verify operation (turn on momentarily from cockpit)

RIGHT SIDE OF FUSELAGE

• Same fuselage skin inspection as left side • Inspect the right static port

RIGHT WING

• Wing tip and navigation light (green): verify condition • Aileron: check for freedom of movement, hinges, and counterbalance • Flap: inspect condition and track • Wing leading edge: check for dents or damage (especially important after flying in rain) • Fuel tank vent: clear of obstructions • Fuel quantity: visually check fuel level through the filler cap. Compare with cockpit gauge reading. • Fuel sample: drain fuel from the wing sump into a clear container. Check for proper color (100LL is blue), absence of water (water settles to the bottom and appears as clear bubbles), and absence of sediment or contamination

NOSE SECTION AND ENGINE

• Cowling: secure, no loose fasteners • Engine oil: check the dipstick. Minimum and maximum levels are specified in the POH (typically 5-8 quarts minimum for most Lycoming and Continental engines) • Oil filler cap: secure • Propeller: inspect for nicks, cracks, and erosion. Run fingers along the leading edge to feel for damage not visible to the eye • Spinner: check for cracks and security • Carburetor air filter: clean and secure • Exhaust pipe: check for cracks, especially at welds • Nose wheel and tire: proper inflation, no flat spots or cord showing. Check the nose strut extension. • Pitot tube: clear of obstructions. Remove the pitot cover if installed.

LEFT WING

• Same inspection as right wing (fuel, aileron, flap, leading edge) • Navigation light (red): verify condition • Stall warning indicator: check by gently lifting the detector tab to verify cockpit horn sounds • Landing light: verify lens is intact

MAIN LANDING GEAR

• Tires: check inflation, tread wear, and sidewall condition on both main wheels • Brakes: check brake pads for adequate thickness and hydraulic lines for leaks • Struts (if retractable gear): verify proper extension • Wheel fairings (if equipped): check for cracks and security

FUEL SAMPLING BEST PRACTICES

Water contamination in fuel is a leading cause of engine failures. Sample fuel from every drain point: both wing sumps, fuel strainer (gascolator), and any additional tank drains. Sample after the aircraft has been sitting (water settles over time). If water is found, continue draining until only clean fuel flows, then recheck all sumps. In cold weather, be especially vigilant for ice crystals in the fuel.

BEFORE ENGINE START

After completing the walkaround, return to the cockpit and verify: • Seats adjusted and locked in position (seat rail security is critical — seat slippage during takeoff has caused fatal accidents) • Seat belts and shoulder harnesses fastened for all occupants • Flight controls: full and free movement (ailerons, elevator, rudder) • Trim set for takeoff • Fuel selector on the correct tank (or BOTH if applicable) • Mixture rich (for carbureted engines at sea level) • Primer in and locked • Radios and avionics set • Altimeter set to current barometric pressure • Transponder set to standby or 1200

WHEN TO REFUSE TO FLY

Certain preflight findings require grounding the aircraft until maintenance is performed: • Any structural damage (cracks in the wing spar, bent landing gear) • Water in fuel that cannot be fully drained • Oil below minimum quantity or evidence of oil leaks • Propeller damage (any crack, no matter how small) • Inoperative required instruments or equipment (check the MEL or KOEL in the POH) • Missing or expired inspections • Any control surface that does not move freely or has excessive play

The pilot in command has the final authority and responsibility for the safety of the flight. When in doubt, do not fly.