Propeller Maintenance
Blade inspection and dressing of nicks, tracking and balancing, blade angle and functional checks, and shock-load inspection.
Propeller maintenance, summary notes
- Blades are inspected for nicks, gouges, cracks, corrosion and erosion. Because a propeller is a highly stressed rotating part, even a small nick on a leading edge is a STRESS RAISER that can grow a fatigue crack, it must be dressed out and blended smooth within the manufacturer's limits.
- Blade TRACKING checks that all blade tips sweep through the same plane (within a small tolerance); an out-of-track blade indicates a bent blade or hub problem and causes vibration.
- Propellers are STATICALLY and DYNAMICALLY balanced; dynamic (in-place) balancing with a vibration analyser and trim weights cures many vibration complaints.
- Blade angle is checked with a protractor; governor rigging, pitch-range stops, and feathering/reverse operation are functionally checked; attachment bolts are torqued and locked.
- A propeller ground strike or sudden engine stoppage requires a mandatory shock-load inspection of the engine and propeller, a bent blade or damaged hub/crankshaft may not be obvious.
- ⚠ Exam trap: a nick in a blade is a stress raiser and must be dressed out and blended (not ignored) to prevent a fatigue crack; blade tracking confirms all tips run in the same plane; a prop strike mandates a shock-load inspection.
A technician finds a small sharp nick on the leading edge of an aluminium propeller blade. Why can it not be left, and what is done?
The blade is a highly loaded rotating part under constant cyclic stress. A sharp nick concentrates stress at its root and can initiate a fatigue crack that propagates until the blade fails catastrophically. The nick must be carefully filed out and blended into a smooth radius within the manufacturer's allowable limits, restoring a stress-free surface, then the blade re-protected.
Maintenance concept map
Propeller Maintenance
Propeller maintenance quiz
Propeller Maintenance, quiz
1. A small nick on a propeller blade leading edge must be:
Dressed out and blended within limitsLeft alonePainted over only2. A nick is dangerous because it is a:
Stress raiser that can start a fatigue crackSource of extra thrustCooling feature3. Blade tracking checks that:
All blade tips sweep the same planeThe blades are the right colourThe oil is clean4. Dynamic balancing of a propeller is done to:
Cure vibration using trim weightsIncrease RPMChange the pitch range5. Blade angle is measured with a:
ProtractorTensiometerMicrometer only6. After a propeller ground strike, the engine and prop require:
A mandatory shock-load inspectionNo action if it still runsOnly a repaint7. An out-of-track blade usually indicates:
A bent blade or hub problemCorrect riggingA fuel fault8. Propellers are balanced:
Statically and dynamicallyNeverOnly when new