There are several important points to understand before you attempt to perform your own preventive maintenance:

First, you need to understand that authorized preventive maintenance cannot involve complex assembly operations.

Second, you should carefully review 14 CFR Part 43, Appendix A, Subpart C (Preventive Maintenance), which provides a list of the authorized preventive maintenance work that an owner pilot may perform.

Third, you should make a self-analysis as to whether or not you have the ability to perform the work satisfactorily and safely.

Fourth, if you do any of the preventive maintenance authorized in 14 CFR Part 43, you will need to make an entry in the appropriate logbook or record system in order to document the work done. The entry must include:

• A description of the work performed, or references to data that are acceptable to the Administrator.
• The date of completion.
• The signature, certificate number, and kind of certificate held by the person performing the work. Note that the signature constitutes approval for return to service only for work performed.

• Removal, installation, and repair of landing gear tires.
• Servicing landing gear wheel bearings (e.g., cleaning and greasing).
• Servicing landing gear shock struts (e.g., adding oil, air, or both).
• Replacing defective safety wire or cotter keys.
• Lubrication not requiring disassembly other than removal of nonstructural items (e.g., cover plates, cowling, and fairings).
• Replenishing hydraulic fluid in the hydraulic reservoir.
• Applying preservative or protective material to components where no disassembly of any primary structure or operating system is involved, and where such coating is not prohibited or contrary to good practices.
• Replacing safety belts.
• Replacing bulbs, reflectors, and lenses of position and landing lights.
• Replacing or cleaning spark plugs and setting of spark plug gap clearance.
• Replacing any hose connection, except hydraulic connections.
• Replacing and servicing batteries.
• Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces. (Note: For balloons, includes the making of small fabric repairs to envelopes, as defined in, and in accordance with, the balloon manufacturer's instructions; and which do not require load tape repair or replacement.)
• Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

Propeller Check

Items to check include:

• Spinner and back plate for cracks or looseness.
• Blades for nicks or cracks.
• Hub for grease or oil leaks.
• Bolts for security and safety wire.

Engine Check

Tasks to perform include:

Preflight engine.

Run up engine to warm-up, and check:

• Magnetos for RPM drop and ground-out.
• Mixture and throttle controls for operation and ease of movement.
• Propeller control for operation and ease of movement.
• Engine idle for proper RPM.
• Carburetor heat or alternate air.
• Alternator output under load (e.g., landing light in "on" position).
• Vacuum system (if installed) for output.
• Temperatures (CHT, oil, etc.) within proper operating range.
• Engine and electric fuel pumps for fuel flow or fuel pressure.
• Fuel selector, in all positions, for free and proper operation.

• Remove engine cowling. Clean and check for cracks, loose fasteners, or damage.
• Check engine oil for quantity and condition. Change oil and oil filter; check screens.
• Check oil temperature "sensing" unit for leaks, security, and broken wires.
• Check oil lines and fittings for condition, leaks, security, and evidence of chafing.
• Check oil cooler for condition (damage, dirt, and air blockage), security, leaks, and winterization plate (if applicable)
• Clean engine.
• Remove, clean, and check spark plugs for wear. Regap and reinstall plugs, moving "top to bottom" and "bottom to top" of cylinders. Be sure to gap and torque plugs to manufacturer's specifications.
• Check magnetos for security, cracks, and broken wires or insulation.
• Check ignition harness for chafing, cracked insulation, and cleanliness.
• Check cylinders for loose or missing nuts and screws, cracks around cylinder hold-down studs, and for broken cooling fins.
• Check rocker box covers for evidence of oil leaks and loose nuts or screws.
• Remove air filter and tap gently to remove dirt particles.
• Replace air filter.
• Check all air inlet ducts for condition (no air leaks, holes, etc.)
• Check intake seals for leaks (fuel stains) and check clamps for security.
• Check condition of priming lines and fittings for leaks (fuel stains) and check clamps for security.
• Check condition of exhaust stacks, connections, clamps, gaskets, muffler, and heat box for cracks, security, condition, and leaks.
• Check condition of fuel lines for leaks (fuel stains) and security.
• Drain at least one pint of fuel from each fuel filter, each fuel tank sump, and any other aircraft fuel drain into a clean, transparent container in order to check for water, dirt, wrong type of fuel, and any other type of contamination.
• Visually check vacuum pump and lines for missing nuts, cracked pump flanges, and security.
• Check crankcase breather tubes and clamps for obstructions and security.
• Check crankcase for cracks, leaks, and missing nuts.
• Check engine mounts for cracks or loose mountings.
• Check engine baffles for cracks, security, and foreign objects.
• Check wiring for security, looseness, broken wires, and condition of insulation.
• Check firewall and firewall seals.
• Check generator (or alternator) and starter for security and safety of nuts and bolts.
• Check brake fluid for level and proper type.
• Lubricate engine controls: propeller, mixture, and throttle.
• Check alternate air source "door" or carburetor heat to ensure that "door" has a good seal when closed, and check "door" operation.
• Reinstall engine cowling.

Cabin Check

• Cabin door, latch, and hinges for operation and worn door seals.
• Upholstery for tears.
• Seats, seat belts, and adjustment hardware.
• Trim operation for function and ease of movement.
• Rudder pedals and toe brakes for operation and security.
• Parking brake.
• Control wheels, column, pulleys, and cables for security, operation, and ease of movement.
• Lights for operation.
• Heater and defroster controls for operation and ducts for condition and security.
• Air vents for general condition and operation.
• Windshield, doors, and side windows for cracks, leaks, and crazing.
• Instruments and lines for proper operation and security.

Fuselage and Empennage Check

• Baggage door, latch, and hinges for security and operation; baggage door seal for wear.
• Battery for water, corrosion, and security of cables.
• Antenna mounts and electric wiring for security and corrosion.
• Hydraulic system for leaks, security, and fluid level.
• ELT for security, switch position, and battery condition and age.
• Rotating beacon for security and operation.
• Stabilizer and control surfaces, hinges, linkages, trim tabs, cables, and balance weights for condition, cracks, frayed cables, loose rivets, etc.
• Control hinges for appropriate lubrication. Static ports for obstructions.

Wing Checks

• Wing tips for cracks, loose rivets, and security.
• Position lights for operation.
• Aileron and flap hinges and actuators for cleanliness and lubrication.
• Aileron balance weights for cracks and security.
• Fuel tanks, caps and vents, and placards for quantity and type of fuel.
• Pilot or pitot-static port(s) for security and obstruction.

Landing Gear Check

• Strut extension.
• Scissors and nose gear shimmy damper for leaks and loose or missing bolts.
• Wheels and tires for cracks, cuts, wear, and pressure.
• Hydraulic lines for leaks and security.
• Gear structure for cracks, loose or missing bolts, and security.
• Retracting mechanism and gear door for loose or missing bolts and for abnormal wear.
• Brakes for wear, security, and hydraulic leaks.

Functional Check Flight

• Brakes for proper operation during taxi.
• Engine and propeller for power, smoothness, etc. during runup.
• Engine instruments for proper reading.
• Power output (on takeoff run).
• Flight instruments.
• Gear retraction and extension for proper operation and warning system.
• Electrical system (lights, alternator output).
• Flap operation.
• Trim functions.
• Avionics equipment for proper operation (including a VOR or VOT check for all VOR receivers).
• Operation of heater, defroster, ventilation, and air conditioner.

1. Ensure that the aircraft is in compliance with all application Airworthiness Directives (ADs), and that compliance has been properly documented in the aircraft records. If the AD involves recurring action, know when the next action is required.

2. Comply with recommended service bulletins and service letters. (Note: These are recommendations unless an AD requires compliance.)

3. See that a current FAA-approve Flight Manual or Pilot's Operating Handbook with all required changes is aboard, and that all required placards are properly installed.

4. Check that the Certificate of Airworthiness and Aircraft Registration are displayed. Check for an FCC radio station license, if required for international operations.

5. Verify that all FAA-required tests involving the transponder, the VOR, and the static system have been made an entered in the appropriate aircraft records.

It pays to take good care of your engine. Good maintenance is not cheap, but poor performance can be disastrously expensive.

If you are unqualified or unable to do a particular authorized job, you must depend on competent and certificated aircraft maintenance technicians to perform the job. Always use FAA-approved parts.

You can save money and have a better understanding of your aircraft if you participate in the maintenance process.

If you do some of your own preventive maintenance, do it properly. Make sure that you complete the job you start, and that you make all of the required record entries.

Money, time, and effort spent on maintenance pays off. If also ensures that your aircraft will have a higher resale value if you decide to sell.

Remember, a well-cared-for aircraft is a safe aircraft. A safe aircraft needs to be flown by a competent and proficient pilot. Maintain both your aircraft and yourself in top-notch condition.

Additional Reading

• Advisory Circular (AC) AC 20-106, Aircraft Inspection for the General Aviation Aircraft Owner.
• 14 CFR Part 39, Airworthiness Directives.
• 14 CFR Part 43, Preventive Maintenance, Rebuilding, and Alteration.