Accident Details
On September 15, 2014, at approximately 1230 Pacific daylight time, a Piper PA-28-150, registration N5948W, experienced severe vibrations during flight, prompting the pilot to initiate a forced landing into a meadow approximately 15 miles southwest of Lone Pine, California. The pilot sustained serious injuries, and the airplane sustained substantial damage to both wings. The personal flight was conducted under 14 Code of Federal Regulations Part 91 in visual meteorological conditions; no flight plan was filed. The flight originated from Reid-Hillview Airport in San Jose, California, at 1040.
Pilot Report
The pilot reported that two hours into the flight, he observed a "flash of something" departing from the front of the airplane. Immediately, the airplane began shuddering and vibrating violently. The pilot reduced the throttle to idle and searched for a clear landing area. With the engine at idle, he noticed that approximately half of one propeller blade was missing. He also observed considerable movement in the front of the airplane. He descended rapidly toward a clearing; as he approached, he saw large rocks that the airplane barely cleared. The pilot held the nose up as long as possible. The left landing gear contacted the ground first and separated, followed by the right landing gear. When the nose wheel touched down, it collapsed, and the airplane slid on its belly until it struck a rock and came to rest.
Propeller Examination
The propeller assembly was sent to Hartzell Propeller Inc. for examination, conducted in the presence of a Hartzell representative. The examination revealed that both propeller blades were positioned in a high pitch angle. One blade was intact but exhibited extensive spanwise scoring and chordwise/rotational scoring near the tip. The other blade was fractured approximately 24 inches from the blade butt. The propeller hub was disassembled and the blades removed. The pitch change knob on the fractured blade was bent, while the pitch change knob on the intact blade was fractured.
Examination of the fracture surface of the fractured propeller blade showed fatigue failure characteristics, with the fatigue origin located at a stress raiser approximately 1.25 inches from the leading edge on the lower blade surface. A distinct score line, serving as a witness mark, was present at the fatigue origin site.
Maintenance History
The airplane's most recent maintenance was an annual/100-hour inspection performed on August 21, 2014, at a tachometer time of 2,096 hours. The propeller total time in service at that inspection was 2,049 hours. During the inspection, the leading edges of the propeller blades were filed.