Initial Inspection
 

Both fixed pitch and variable pitch propellers follow these procedures.

When the propeller arrives it is assigned a work order, inspection form, and a cart that will travel with it throughout the overhaul process.

Propeller model number and aircraft application is researched for Service Bulletins and Airworthiness Directives pertaining to it.

An inspection of the propeller is made to determine if it is malfunctioning, misadjusted, or damaged.

Work order initiated                             Angles being checked                         Track being checked
 

Disassembly

   
Deice boot being removed                      Propeller being disassembled          Disassembled
 

Cleaning

Our environmentally friendly parts washer removes the majority of grease and oil.  Media blasting removes paint and other adhesives.

Prop in parts washer                            Blade being media blasted                  Hub being media blasted
 

Stripping

All coatings are removed prior to inspection. The anodized or alodined aluminum parts and the cadmium plated steel parts are chemically stripped.

The blade's airfoil is reworked to remove nicks and dings received during operation.  This process also stress relieves the blade.

Anodizing and stripping line                   Cadmium plating and stripping line       Blade being  reworked
 

Inspections

Some parts require mandatory replacement at overhaul or due to Service Bulletins or A/Ds.

Parts are visually inspected for damage, corrosion, and defects. Depending on the part, some damage and corrosion can be worked out. Parts are then dimensionally inspected.  

Blade width, thickness, angles, and face alignment are checked at various blade stations. If the face alignment (the fore and aft bend) or angles (twist) of the blade are out of manufacturer's requirements, it is corrected at this time.  This is a time consuming job, but when done correctly, will aide in making a smoother flying propeller.

Once the parts have passed the visual inspections, they move on to NDT or Non Destructive Testing. The following methods are used for finding cracks and other defects.  We use three forms of NDT- Eddy Current, Dye Penetrate, and Magnetic Particle. 

Eddy Current                                         Dye Penetrant                                          Magnetic Particle 
 

Rework

If a part requires a modification or rework, it is sent to our machine shop.  After rework or modifications the parts go back to the inspections department before going on to re-finishing. 

 Lathe                                                          Mill                                                               Surface Grinder
 

Refinishing

Blades, hub, and some internal parts are anodized or cadmium plated for corrosion protection. After cadmium plating, parts are baked in an oven for 8 hrs. at 350 degrees to prevent hydrogen embritalment.  After chemical treatment, some parts are then painted for further protection.

Blades after anodizing                              Oven for cadmium plated parts             Blades being painted

Assembly

New parts are pulled from our inventory and assigned to the propeller's work order.  Sub assemblies are built up.  The propeller is then assembled.  Angles are set and the propeller is actuated. If the propeller requires deice boots they are installed now.  The last thing to be done is static balance and final inspection.

New Parts                                              Propeller ready for assembly                 Sub assembly build-up

Assembly of clamped Hartzell                Assembly of Hamilton Std.                  Assembly of threaded McCauley

Assembly of threadless McCauley          Deice boot installation