Ryan Aeronautical ST3KR N48701 accident near Hollister, California

Probable cause

The pilot's failure to observe the runway environment while operating in the traffic pattern and his subsequent failure to maintain clearance from a lawnmower on the runway during the landing roll. Contributing to the accident was the lawnmower operator's decision to remain on the runway while troubleshooting the mowing equipment without monitoring the airport's common traffic advisory frequency.

NTSB analysis

Following an uneventful flight in the tailwheel-equipped airplane, the pilot entered the airport traffic pattern for the nontowered airport, which featured a single turf runway. The pilot announced his position on the airport's common traffic advisory frequency (CTAF). The pilot continued to turn onto the base leg and then onto final, announced his position on each segment, and landed in a 3-point attitude. During the landing roll, the airplane struck a stationary, occupied lawnmower and a truck on the right side of the runway. The pilot further reported that he did not see the lawnmower while he was in the traffic pattern or during the landing sequence. The driver of the truck, who was talking to the person operating the lawnmower, reported that they were located on the right side of the runway, just beyond a turnoff to the taxiway, and were discussing an issue with the mower. The driver further reported that the lawnmower operator did have a headset connected to an aircraft transceiver; however, he was not wearing it during the conversation.

It is likely that the nose-high attitude of the tailwheel-equipped airplane and the pilot's position in the rear seat reduced the pilot's forward visibility during the landing and subsequent landing roll precluded his ability to see objects directly in front of the airplane. However, the pilot would have had adequate visibility to inspect the runway for obstructions while operating in the traffic pattern. In addition, if the lawnmower operator had been using the transceiver to monitor the CTAF, it is likely that he would have heard the approaching airplane and repositioned the lawnmower off the runway before the airplane landed.

Text from the NTSB. Open the NTSB docket for WPR15LA233 for the full record.