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Troubleshooting of piston powered propellers with blade seal leakage

Following installation of a new three blade McCauley propeller it is common to see some leakage from the blade seal. Models affected include All C200, C300, C400, and C500 oil filled propellers. This includes the McCauley 'Blackmac' 401 propeller that Air Plains Services sells and holds a number of STCs for.

Service information is to be added to appropriate McCauley Service Manual until next manual revision is issued. Service manuals affected include 701115, 761001, 780630, 810915. Please use link below to download the complete three page document. Please note this article serves as a basic summary and does not in any way replace the complete approved document.

In summary McCauley states the following when checking/correcting leaking propeller:

  1. Clean the blade of all traces of oil and dirt using a cloth dampened with mineral spirits.

  2. Run engine and cylce propeller at least five times.

  3. Inspect blade for continued oil leakage and clean if necessary per step 1.

  4. Repeate step 2.

  5. Inspect blade. Leaking should be tapering off or completely stopped.

  6. If leaking has stopped no further action is needed.

  7. If leaking has decreased, continue operation for up to 20 hours. If leaking continues after 20 hours, propeller must be removed from aircraft and sent to an approved propeller shop for repair.

Click below to download the complete document:

1998-24 McCauley Service Letter
Download PDF • 264KB


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