Preventive Maintenance

Back to Maintenance

Preventive Maintenance; What you can do.

byNorm Echtinaw A&P/IA

Saving money is one good reason aircraft owners perform Preventive Maintenance. Another important benefit is the opportunity to learn about your aircraft. If a mechanical problem occurs during a flight, a pilot with an intimate knowledge of the aircraft will be more proficient in handling the situation than one who is not familiar with the aircraft.

Many aircraft owners are hesitant to work on their aircraft for various reasons, including not understanding the regulations applying to preventive maintenance. There are many relatively simple maintenance tasks that can be performed by an aircraft owner that can reduce maintenance costs and provide opportunities to learn about your aircraft.

Regulations

Preventive maintenance is defined in FAR Part 1 and describes preventive maintenance as “simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations.” A list of operations that the FAA considers preventive maintenance can be found in Part 43, Appendix A (c).

Who can perform preventive maintenance, what aircraft can you work on, and what information do you need prior to working on your aircraft?

The holder of a pilot certificate can perform preventive maintenance on an aircraft that he or she owns or operates under Part 43.3. This applies only to aircraft operated under Part 91. Pilots cannot perform preventive maintenance on aircraft operated under Parts 121, 127, 129, or 135.

Although 43.3 does not specify the type of pilot certificate that is required to perform preventive maintenance, 43. 7 does specify at least a private pilot certificate to make the logbook entry. The person making the logbook

entry must be the same person who performed the maintenance.

Part 43.13 requires that preventive maintenance be performed using methods, techniques, and practices acceptable to the Administrator. It also requires that the work performed and material used at least equals the original condition. Information required to properly complete preventive

maintenance can be found in the aircraft and engine manufacturers’ maintenance manuals and parts catalogs, and FAA Advisory Circulars.

Properly completing the work also requires the use of proper tools, equipment, and test apparatus. In addition to the manufacturers’ maintenance

manuals and parts catalogs there are two essential Advisory Circulars: AC 42-12A Preventive Maintenance and AC 43.13-1B/2A Acceptable Methods Techniques and Practices.

After preventive maintenance has been completed, a logbook entry is required to return the aircraft to service in accordance with FAR 43.9. The logbook entry must include a description of the work performed, date of completion, aircraft time, and type of airman certificate exercised (private pilot, commercial pilot), certificate number and signature. The same person that completed the work must make the logbook entry.

Necessary Tools and Equipment:

Proper tools always make the task easier. A good basic set, plus special tools such as an aviation spark plug socket are essential. Approved parts are an absolute must. For reference on acceptable methods consult AC 43.13-

1B/2A.

If you get in over your head on something, don’t hesitate to ask your mechanic for help.

Removal, disassembly or altering of any primary structure or operating system is NOT considered preventive maintenance.

For those of you with a reasonable degree of mechanical ability here is what the FAR’s say you, as an owner/operator, can legally do. The maintenance manual should be consulted before beginning work.

1. Removal, installation, and repair of landing gear tires.

In most cases this will include removing the brake assembly, and wheel fairings if they are installed.

2. Replacing elastic shock absorber cords on landing gear.

Unless you have done this before and have the proper tools, leave this one to the professionals.

3. Servicing landing gear shock struts by adding oil, air, or both.

Be sure to use the correct hydraulic oil (5606 is most common). Check the

Maintenance manual for adding air or nitrogen.

4. Servicing landing gear wheel bearings; such as cleaning and greasing.

Thorough cleaning with a mild solvent is required followed by a close inspection for pits, corrosion or discoloration from heat damage. Repacking the bearing with grease is easily accomplished with bearing packing tool.

5. Replacing defective safety wiring or cotter keys.

Must use FAA approved safety wire. Use the appropriate size. Most propellers require .041. .020 and .032 are commonly used for other applications. Always safety fasteners in a tightening direction.

6. Lubrication not requiring disassembly other than removal of

nonstructural items such as cover plates, cowlings, and fairings.

This is one of the rules, which allows for an engine oil change.

7. Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces.

Don’t touch those control surfaces!

8. Replenishing hydraulic fluid in the hydraulic reservoir.

Use the same fluid that is in the system MIL-H-5606 is the most common and readily identified with its red color.

9. Refinishing decorative coating excluding balanced control surfaces.

Balanced control surfaces are any flight controls including ailerons, elevator, rudder, flaps and all tabs. Check with the manufacturer for proper finishing techniques and procedures.

10. Applying preservative or protective material to components where such coating is not prohibited or is not contrary to good practices.

Be sure the preservative you use is compatible with the material.

11. Repairing upholstery and decorative furnishings of the cabin or cockpit.

Use only FAA certified materials and stick to the aircraft specifications.

12. Making small simple repairs to fairings, nonstructural cover plates, cowlings, and small patches and reinforcements not changing the contour so it will interfere with proper air flow.

Consult your local repair shop or A&P mechanic on the definition of a simple repair. Use acceptable materials and procedures.

13. Replacing side windows.

No windshields, only side windows.

14, Replacing safety belts.

Follow the service manual closely for precise installation. Use only approved seat belts and look for a TSO number on the belt.

15, Replacing seats or seat parts with replacement parts approved

for the aircraft.

Again use only approved parts and procedures. Do not alter the seats or seat parts.

16. Troubleshooting and repairing broken circuits in landing light wiring circuits.

Use of proper tooling and equipment is critical when splicing wires.

17. Replacing bulbs, reflectors, and lenses of position and landing lights.

Use approved parts.

18. Replacing wheels and skis not requiring weight and balance computation.

19. Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

Cowl flap cables are NOT flight controls.

20. Replacing or cleaning spark plugs and setting of spark plug gap clearance.

When removing the plugs, keep them in order for proper reinstallation. For cleaning, a grit blast of plastic or glass beads is preferred followed with an air blast. Gap checking gauges can be obtained free at most trade shows. For adjusting gap, use the appropriate tooling. Always test the spark plugs before reinstalling. The machine is expensive. Talk to your local shop about using theirs. Rotate and install spark plugs according to the maintenance manual’s recommendation.

21. Replacing any hose connection except hydraulic connections.

22. Replacing prefabricated fuel lines.

Use only approved parts.

23. Cleaning or replacing fuel and oil strainers or filter elements.

This is the other part of the oil change with the provision for removing, cleaning or replacing the oil filter. Watch for AD’s or service bulletins on inspecting oil filters and screens.

24. Replacing and servicing batteries.

For servicing lead-acid batteries, add distilled water if the level is too low. Clean the installation thoroughly to prevent corrosion. Baking soda is a great neutralizer for the electrolyte in lead-acid batteries, but be sure none gets inside the battery. When replacing ELT batteries, be sure to check that the date is legibly stamped on the battery and a proper logbook entry is completed.

25. Replacement of nonstructural standard fasteners incidental to operations.

Consult Advisory Circular 43.13-1B/2A for a list of structural and nonstructural fasteners and their installation methods.

26. Installation of anti-misfueling devices to reduce the diameter of fuel tank filler openings, provided the specific device has been made part of the aircraft type certificate data by the aircraft manufacturer, the aircraft manufacturer has provided FAA-approved instructions for the installation of the specific device, and installation does not involve the

disassembly of the existing filler tank opening.

Follow instructions carefully.

27. Removing, checking and replacing magnetic chip detectors.

Follow manufacturer’s instructions and procedures.

28. Inspection and maintenance tasks prescribed and specifically identified as preventive maintenance in a primary aircraft Type Certificate or STC holder’s special inspection or preventive maintenance program.

29. Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that connect the unit when the unit is installed into the instruments The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided (check regulations for

applicability). Must perform operational check.

30. Updating self-contained front instrument panel-mounted ATC navigational software data bases provided no disassembly of the unit is required and pertinent instructions are provided. Prior to the unit’s intended use, an operational check must be performed.