PC-12
Flight Crew Air Transport Pilot (ATP)
Physiological - Other
Aircraft Equipment Problem Less Severe
General None Reported / Taken
Human Factors; Aircraft
A bright reflection of the sun from the propeller face (in the approximate upper left quadrant) due to an apparently unpainted/ uncoated/ unfinished nickel plated stainless steel leading edge applied to the leading edge of each propeller blade was visible during all phases of aircraft movement on the surface and during all phases of flight; resulting in eye fatigue and distraction due to light glare and reflection.  The event did not occur at night nor did it occur while the propeller was feathered on the ground before engine start or after engine shut down; day or night. The event was most noticeable while flying on top of 100% overcast clouds and continuously if no clouds were present during all phases of taxi or flight.  The event was not a one time occurrence.  The event was a continuous distraction.  Airborne traffic is impossible to see in the precise location of the reflection; momentarily. The movement of shiny reflective parts in factories is generally recognized as a safety hazard in an industrial setting due to eye fatigue and mental distraction.  The airplane is the commercial pilot's industrial setting where staring at the moving propeller on a nose-mounted single engine aircraft can occur upwards of 10 hours per day.  The movement of shiny reflective surfaces on rotating airplane propellers creates eye fatigue and mental distraction due to light glare and reflection of light sources (such as the sun at low astronomical zenith angles during morning or evening hours; or any time during daylight hours during the winter).  Sunglasses (polarized or not) do not mitigate this occurrence. This occurrence is not as much of a distraction on twin engine propeller driven aircraft with wing mounted engines; for comparison; because their propellers are not in line of sight with the cockpit and outside references directly ahead such as a runway (for takeoff and landing) or other air traffic or birds.  At the manufacturing and certificating level; I suggest that either:A) the face ('flat' side or 'back' side) or B) the entire surface of the nickel plated stainless steel leading edge of the MT propeller be made less reflective by one of the following methods; procedures; or processes: 1) Media blasting of either A) the face or B) the entire surface of the nickel plated stainless steel leading edge with approximately 300 - 1;000 mesh sized grit abrasive (such as walnut shells or glass beads or aluminum oxide).  This will scatter the light source resulting in a gray matte appearance which DOES NOT REFLECT bright sources of light.  This is a destructive process which removes material and may need to be offset by thicker nickel plating. 2) Matte black nickel plating.  This process is actually two processes consisting of black nickel plating over matte nickel plating.  Black absorbs light and the matte finish scatters it.  Durability may not reach advertised TBO.  Adds thickness but probably aerodynamically negligible compared to paint or the rubber boot glued to the propeller root. 3) Flat black epoxy paint of the face of the metal strip.  Black absorbs light and the matte finish scatters it.  This coating adds 2 to 4 mil thickness which is 3 to 4 orders of magnitude thicker than plating or conversion coatings yet still less drag than the rubber boot glued to the propeller root. 4) Aluminum plating followed by black aluminum oxide anodizing.  Has the highest hardness rating of '9' for any coating on the Mohs' hardness scale.  Extremely durable and corrosion resistant.  Excellent conductor of heat which helps with anti-ice/de-ice and excellent conductor of electricity which is important for conducting static charge.
PC12 pilot reports reflections from the propeller due to nickel plated stainless steel leading edge; resulting in eye fatigue and distraction due to light glare.