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Propeller Inspection Checklist

Propellers are one of the most critical parts of a well-built and well-maintained aircraft. As such, it’s essential to frequently run through a preflight or “walkaround” propeller inspection checklist. The last thing any pilot wants is to have to make an emergency landing because the propellers has failed.

Stockton Propeller is a full-service propeller overhaul and maintenance facility in Northern California with the needed equipment and expertise to perform the needed inspection and service on your propeller. Get inspection and maintenance before a failure happens on your aircraft. Contact us today.

Why Is Aircraft Propeller Inspection Important?

According to the Aircraft Owners and Pilots Association (AOPA), “the root cause of mechanically induced accidents is almost always neglect.” The AOPA continues:

“On takeoff, propeller tip speeds approach the speed of sound. The blades must absorb not only the punishing vibration of the engine’s power pulses but also vibration caused by the oncoming airstream. Centrifugal loads – those forces that try to pull the blade out of the hub – amount to 10 to 20 tons per blade.

     The blades twist and flex. The stresses imposed on the prop are more concentrated in the small areas that are nicked or cut. These nicks and scratches act as stress risers, which can weaken the blade enough to eventually cause it to fail.

     When an engine quits, the airplane can glide to a safe landing. When a propeller blade is lost, the resulting imbalance can tear the entire engine from the aircraft, putting the center of gravity far beyond limits and rendering the aircraft uncontrollable.”

That scenario, of course, can be avoided with frequent inspections using this propeller inspection checklist. Performing these routine preflight inspections can clue you into any needed propeller maintenance or repairs.

working propeller

Stockton Propeller’s Propeller Inspection Checklist

A “walkaround” or preflight visual inspection of your aircraft’s propellers is vital for your plane’s safety and health. Even more important is the safety of you and your passengers or cargo. 

An important note: While the term “walkaround” may make it sound like this could be just a superficial glance. However,  this should instead be a studied review to gauge your craft’s airworthiness.

To perform a preflight visual propeller inspection, follow these steps:

  1. Get a clear view of the propeller area. In other words, make sure your propellers are clean. In the course of any flight, propellers can pick up dead bugs, dirt, and other pollutants. If your propellers are dirty, it will be challenging to get a good view of any defects. If the propellers are dirty, you can easily wash them off with a simple solution of dish soap and water. If you have to wash off the propeller area, make sure that your propellers are in the down position. This will prevent any liquid from getting into the seals and causing issues there.
  2. Check for surface damage. Carefully and thoroughly examine the aircraft’s propeller blades and other parts for any cracks, nicks, chips, corrosion, or other blemishes. Surface damage can be felt by running a fingernail along the propeller’s edge. For propellers made of wood or composite materials, check for delaminations or microcracks on the propeller surfaces, edges, and glue lines. If your propellers have any drain holes, check that they aren’t clogged. Clogged drain holes can lead to moisture retention and more significant problems down the road.
  3. Check for erosion. Examine the propeller for any and all signs of decay. Look over the paint job on the propeller blades and spinners for any imperfections. This paint on the propeller protects the surface from erosion. If erosion starts to occur, it can be a much more costly fix than having a professional touch up your paint job.
  4. Check for any loose or missing hardware or broken safety wire.
  5. Check for any broken or compromised seals.
  6. Check the straightness of the propeller blades. Perform a simple sight check for any deformations down the edges of the propeller blades. You can determine the straightness of the propeller blades with this simple sight check.
  7. Check for looseness. Flex the propeller blades forward and backward to inspect the intersection for any movement. There should be no movement at all.
  8. Check the hub. Gently shake each propeller blade to feel for blade movement in the hub of the propeller. A small degree – up to ⅛ inch – is allowable. If there is more movement than that, maintenance is needed immediately.
  9. Check for oil or grease leakage. Look for any grease or oil. There should be no oil or grease detected on the propeller blades or spinners. A couple of exceptions are if your propellers are brand new or you are in a hot climate with high RPM conditions.
  10. Update maintenance records. If you notice a small imperfection, make sure to note it in your aircraft’s maintenance records. Your repair person will know when you first saw the issue during a walkaround or preflight inspection. They will also know if the issue gets worse over time.

If, when following this checklist, you don’t see any areas of concern, your propellers are airworthy, and you are good to fly away!

close up of aircraft propeller
close up of aircraft propeller

How Often Should You Inspect Your Aircraft’s Propellers?

Before any flight, you should perform the above visual propeller inspection checklist of your aircraft’s propellers. 

Then, of course, you should follow the manufacturer’s recommendations for your scheduled overhauls and maintenance. Generally, these schedules are based on years and flight hours.
The recommended Time Between Overhaul (TBO) guidelines are mandatory for Part 135 commercial operators, but are only recommended for Part 91 pilots not flying for hire. That being said, Part 91 operators should follow the calendar recommendation for overhaul as a recommendation for inspection/reseal at the 5 or 6 year interval if the prop is less than halfway through the hour recommendation. This gives the prop a good inspection, replaces the aging grease and seals and gives the blades a cleanup and repaint. This will allow the prop to operate safely for another calendar period.

Stockton Propeller is a full-service propeller overhaul and maintenance facility in Northern California with the needed equipment and expertise to perform the needed inspection and service on your propeller. Get inspection and maintenance before a failure happens on your aircraft. Contact us today