Propeller Basics
Part 1
The propeller is a vital component of the aircraft. Nobody can deny that mechanical failure of the propeller can be disastrous! Propellers undergo constant vibration stresses from the engine and air stream, which contribute to high bending and centrifugal stresses.
Before a propeller is certified as being safe to operate on an airplane, an adequate margin of safety must be demonstrated. Keeping your propeller matched to its approved engine and aircraft combination maintains the safety margin. Even though every precaution is taken in the design and manufacture of a propeller, history has revealed rare instances of failures, particularly of the fatigue type.
It is essential that the propeller is properly maintained according to the recommended service procedures and a close watch is exercised to detect impending problems before they become serious. Make it a habit to routinely and carefully observe the propeller’s physical condition. Be wary of grease or oil leakage, loss of air pressure, unusual vibration, or unusual operation as it could be a warning that something serious is wrong. Question everything and have it carefully evaluated before flight. It is “Plane Senseless” to ignore to what your senses are trying to tell you.
For more information, refer to the propeller manufacturer’s maintenance information and to the following FAA Special Airworthiness Information Bulletin’s (SAIB):
- NE-06-13 Using Propellers with Four or More Blades
- NE-08-18 Engine Dampers
- NE-08-19 Propeller Installation on Experimental Aircraft
- NE-08-20 Propeller Maintenance
- NE-08-21 RPM Restrictions & Placards
- NE-08-22 Search Inspection
You can find the specific SAIB at this address: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/MainFrame?OpenFrameSet by entering the SAIB number in the search box.
This month’s Maintenance Safety Tip was sponsored by Hartzell Propeller; Piqua, Ohio.
P.S. Look for Part 2 in your email next month!
