LAX05LA100 · Ayres S2R

The airplane impacted soft muddy terrain during a forced landing following a loss of engine power shortly after departure. The pilot departed with a full load of fertilizer and climbed above several transmission wires before the engine lost power. The airplane pitched down in a nose-low configuration and dove toward terrain. The engine's most recent inspection occurred about 2 months prior to the accident. The logbook entry for that inspection stated that the mechanic performed a hot section inspection at which time the compressor turbine (CT) disk was reinstalled with 3,595 cycles remaining. A post accident examination of the engine revealed that a CT blade had failed in fatigue initiating in the fir tree root. Near the fatigue origin, no surface damage was observed and no material anomalies were found on the fracture surface; the reason for the fatigue failure was never definitively determined. The blade was likely manufactured under a Parts Manufacturer Approval (PMA). The Safety Board Materials Laboratory reported that the chemistry of the fractured blade appeared to be consistent with the PMA specified alloy and not to the material specification the original equipment manufacturer (OEM) utilizes. A review of the Safety Board database revealed an instance of a very similar failure on an OEM manufactured CT blade. Evidence of recent marijuana use was found on toxicological evaluation, and the pilot might have been impaired ..." It is not clear whether this impairment adversely affected the pilot's actual actions during his response to the loss of engine power.

Verbatim NTSB analysis and probable cause from the NTSB dataset