Accident Overview
On October 3, 2014, about 1330 mountain daylight time, an experimental Thomas D. Gaston Thunder Mustang, registration N51TG, crashed during approach to landing at Council Municipal Airport in Council, Idaho. The pilot, who was the sole occupant, sustained fatal injuries, and the airplane was destroyed by impact forces. The flight was being conducted under 14 CFR Part 91 as a local personal flight that departed Council at an undetermined time. Visual meteorological conditions prevailed, and no flight plan was filed.
Pilot Information
The 75-year-old pilot held an airline transport pilot certificate with ratings for single-engine land, multiengine land, and instrument airplane, as well as a repairman experimental aircraft builder certificate. He held a third-class medical certificate issued on June 30, 2014, with limitations requiring corrective lenses for distant vision and glasses for near vision. He reported 18,500 total flight hours with 25 hours in the last 6 months on his medical application.
Aircraft Information
The airplane was an experimental amateur-built Thunder Mustang, serial number EITM027. The total airframe time was 222.8 hours at the last conditional inspection on July 1, 2013. The last logbook entry was dated October 2, 2014, for a conditional inspection signed by the pilot/builder, but no aircraft times were recorded. The engine was a Falconer V-12, serial number 12027, with unrecorded total time and 0.0 hours since major overhaul. The engine logbook entry on October 2, 2014, stated the engine was test run and safe for flight. The engine was equipped with two MoTec M48 Engine Control Units (ECUs).
Witness Observations
Witnesses reported that during a flight after the pilot had performed maintenance on the engine, the pilot radioed that he was having an engine oil pressure issue and was returning to the airport. One witness observed the airplane flying a normal pattern until it turned base closer to the airport than normal. The airplane then turned onto final making descending "S" turns, followed by a very hard right turn toward north-northeast about 100 feet above the ground. The witness watched the airplane fly away from the airport and lost sight of it.
Wreckage and Impact
The accident site was in a rocky field about 1/3 mile northwest of the approach end of runway 17. The first identified point of contact was a ground scar. The airplane impacted the ground at a shallow angle, and the fuselage broke apart as it slid approximately 60 feet along a heading of 318° true. The engine broke loose and slid another 15 feet. The gear reduction case and propeller hub continued another 25 feet with one blade intact and largely undamaged; no rotational damage was noted to the propeller.
Engine Examination and ECU Data
Examination of the recovered engine revealed no evidence of preimpact mechanical malfunction. The lower oil pan was removed and the bottom end showed no signs of thermal damage or oil starvation. However, a foreign substance consistent with shredded blue paper shop towels was found in the oil pan and throughout the oil cavity. Review of the aircraft records showed limited detail about work performed on the airframe or engine.
Data downloaded from the two ECUs showed that the engine lost oil pressure 110 seconds prior to the accident. Engine RPM correlated with throttle position throughout the flight; at impact, RPM was 2,000. All other recording parameters appeared normal until impact.
Toxicology and Autopsy
An autopsy ruled the cause of death as blunt force trauma from the accident. Toxicological testing detected 0.034 µg/ml diphenhydramine in blood cavity; no carbon monoxide or volatiles were found. No significant natural disease was identified.