Any Unknown or Unlisted Aircraft Manufacturer
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Ground Event / Encounter Ground Strike - Aircraft; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Taxiway
Airport; Human Factors
After Landing at SGT under VFR I turned off runway 36 at slightly too high a speed. Two factors related to this. I believed I had following traffic that was not on the CTAF; as I had observed that aircraft in the pattern behind me. But primarily I elected to turn off too soon because of a slight hump in the runway obscuring my vision of the runway remaining. This was partially due to the very low height of the Onex type aircraft on the ground and a supine seating position within it. Other types would not likely experience this obscuration due to the geography of the runway. Not being familiar with the airport I believed myself to be running out of runway when I still had sufficient runway remaining. Turning off seemed to be the best choice at the moment. I understood that I was risking a ground loop by doing so. In fact a ground loop did occur on the taxiway after having left the runway. This put my aircraft in the grass off the taxiway; but had not caused any damage to the aircraft. The ground loop ended with me facing toward the runway again and under pilot control of the aircraft. I chose to taxi back onto the runway as I could see no landing or departing traffic. Upon reaching the edge of the runway pavement my left main gear dropped into a depression. The runway pavement itself was raised above the level of the ground causing an edge of at least 10 inches above the ground. My left wheel pant struck this edge cracking the fiberglass pant. At the same time; the propeller struck the raised surface of the runway; shattering the wood/composite prop; and causing significant damage to the aircraft. The engine did not stop and I subsequently had to shut it down. If damage was done to the engine that is yet to be determined by breaking the engine down for inspection. I was unable to see this raised edge of the runway pavement as it was obscured by uncut grass. (At the time the grass was in fact in the process of being mowed; but had not yet gotten to that area.)The safety issue here is the raised edge of the runway above the ground level. In all my experience at other airports it has been possible to taxi from grass alongside a runway onto the paved surface safely. Some smaller airports do not even have paved taxiways and it is necessary to taxi from grass onto the paved runway. Taxiing to and from the paved runway from the grass next to it is a common procedure. I was taken by surprise by the particular geography of the runway at KSGT; and believe that the same could happen to any other pilot unfamiliar with the airport; or any other airport with a similarly raised paved runway.I suspect that the problem came about over the years as the runway surface was refreshed by adding additional paving material on top of the older material; over the years raising the runway surface considerably. At the same time no filling in was done to raise the ground level alongside the runway to the same height.My recommendation is that runways should be inspected for evenness with the ground level alongside them and that any found to have a considerable difference between the runway surface and the ground level should be filled to remove this discrepancy.
GA pilot reported a propeller strike taxiing back onto runway 36 at SGT after a taxiway excursion that left the aircraft in the grass.