PROPELLER CARE
PREVENTIVE MAINTENANCEVisual Inspections
Prop blades should be visually inspected regularly, preferably before each flight. Look for surface damage and irregularities such as dents, nicks or scratches. These imperfections should be dressed out by an A&P mechanic before cracks have a chance to develop. Minor repairs should not impair propeller performance. If you have a spinner, check external surfaces for damage and the attachment parts for normal tightness. If no spinner is installed, visually examine the front and back surfaces of the propeller hub and its attachment onto the engine shaft for normal tightness. At least once a year (for one-piece, fixed-pitch propellers) or every 100 flight hours (for all other types of props), inspect every inch of the prop in the best possible light, looking for any evidence of damage. Have an approved, FAA-licensed A&P mechanic remove the spinner (if installed) and have the propeller installation bolts checked for tightness with a torque wrench.
Preventing Damage
High-speed operation of the propeller when standing or taxiing over dirt, gravel or loose stone can cause nicks and other damage to blades. Never use prop blades as handles to maneuver a plane on the ground. Either use a tow bar on your planešs steerable nose wheel, or use the areas of the airframe designated by the manufacturer as safe for push/pull pressure. Pulling or pushing with the propeller could severely damage actuating components inside the hub.
Cleaning the Prop
Use a clean cloth dampened with light oil to wipe the prop after each flight, or as regularly as possible, especially if you operate near salt water or fly a sea plane. The oil removes and repels substances that cause corrosion and helps prevent water erosion. Never scrape the blades, use abrasive cleaners or use water to clean the propeller or hub. Forcing water into the hub can lead to corrosion or lubricant breakdown. If waxing the blade camber side, wipe first with a non-oil base solvent.
Repainting Prop
Blades If repainting is required, use non-reflective black for the side of the blades which face the pilot, so that the spinning propeller is not seen as a shiny, hypnotic disc. Paint blade tips on the opposite side (face side) with bright colors so that the spinning propeller can be more easily seen by people walking near it on the ground.
Checking BladeTrack
Blade track is the ability of one blade to follow the other in the same plane of rotation. Track is held to reasonable limits to prevent roughness. To check track, place a smooth board just under the tip of the lower blade. On controllable props, move the tip fore and aft carefully through its small range of motion, making small pencil marks at each position. Center the blade between these marks and draw a line the full width of the blade. Repeat this procedure with another blade tip. The lines should be separated by not more than 1/16 inch. Differences greater than 1/16 inch may be an indication of bent blades, improper installation or foreign particles between the hub and crankshaft mounting faces.
Roughness
All props vibrate to some extent during operation. Assuming that the engine itself is not at fault, propeller roughness may be caused by bent blades, blades out of track due to improper mounting of the prop on the engine shaft, imbalance, a propeller loosely mounted on engine shaft, blade angles between blades out of tolerance with respect to each other and spinner imbalance due to improper mounting or to dirt, snow or ice inside the shell.