Prop Overhaul Process
Safety, quality and client satisfaction are our top priorities. Here is what you can expect, step-by-step, when you send us your propeller for your scheduled or as-needed overhaul:
Hartzell four-blade prior to disassembly, showing wear and corrosion on the tips and leading edge.
Visual Inspection & Disassembly
Upon receiving your propeller, we will complete a visual inspection to detect any obvious issues that may cause all or part of the prop to fail. Such issues may include excessive, irreparable corrosion on the blades and hub, or severe damage from a foreign object or ground strike. Once the visual inspection is complete, we will conduct a preliminary bench check to assess any performance issues, then disassemble the prop and clean all parts in preparation for overhaul.
Fixed-pitch, refurbished and ready for NDT.
refurbish the blades
Before any work is done on the blades, we use digital Vernier calipers to measure width and thickness at various stations to assure the blades are above minimum manufacturer specifications. If so, then all paint is removed from the blades, and any corrosion, nicks and dings are filed and sanded out before giving the blade a final polish. At this point we will also do a preliminary static balance and obtain final measurements.
Dye penetrant solution applied to Hartzell blade shanks. They will be inspected for defects under UV light.
NDT Process
The blades and hub are then etched in a caustic solution and subjected to a series of Non-Destructive Testing procedures as outlined in the manufacturer's overhaul manual. Depending on the component, magnetic particle, eddy current, and/or a dye penetrant process may be employed. Once processed, the knobs and blades are shot peened if necessary. While we do a small amount of in-house shot peening, larger components are outsourced to a more specialized facility. The blades and hub are then Alodined and given a fresh coat of paint.
Hartzell Three-Blade Composite Propeller
Reassembly
Your propeller is then reassembled according to the manufacturer's specifications. Each manufacturer specifies a number of components that must be replaced at each overhaul, including seals, mounting studs, bolts, o-rings and various other parts depending on the make and model of the propeller. All Airworthiness Directives, Service Bulletins and Service Letters are reviewed and complied with. The propeller is properly lubricated and a static balance performed. Of course, we recommend a dynamic balance once the propeller is re-mounted on the aircraft.
From start to finish, meticulous records are kept at every stage of the process and become part of the work order. We will issue an 8130-3 Airworthiness Approval tag upon the completion and return of your propeller. Happy Flying!