LAX05LA270 · Prescott Aeronautical Pusher

The pusher configuration propeller departed the airplane during flight and the airplane impacted trees during a forced landing in a field. The pilot was established in cruise flight at 7,500 feet mean sea level when he felt a vibration. The vibration then became "severe" and he heard a series of clinking noises. He immediately began preparations for an emergency landing because he knew that his propeller had separated from the airplane. The pilot force-landed the airplane in a vacant field. The pilot stated that about 2 weeks prior to the accident he had removed the wooden American Propeller and installed a different propeller. The new propeller was too long for ground clearance so the pilot reinstalled the original wooden American Propeller. The original hardware was used to install the propeller and the bolts were torqued to the recommended amount. The bolts were also safety wired. After its installation, the propeller was operationally tested. Prior to its removal, the propeller had been installed on the airplane for about 1 year with no operational or mechanical problems noted. The pilot did not have any other reported vibrations on flights leading up to the accident. Post accident examination by the responding airport personnel showed that the propeller and the attachment bolts were not on the propeller flange. Three of the bolt holes showed evidence of rubbing and partial elongation of the holes. The propeller and its attachment hardware were not recovered.

Verbatim NTSB analysis and probable cause from the NTSB dataset