History of Flight
On August 3, 2017, at 1503 Pacific daylight time, an experimental, amateur-built Lancair IV-TP, registration N420M, was substantially damaged in an accident near Rio Linda, California. The commercial pilot was fatally injured. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
The flight departed Auburn Municipal Airport (AUN), Auburn, California, about 1455, en route to San Carlos, California. The pilot established a heading of about 195° and began climbing. He contacted air traffic control and requested visual flight rules flight following. After the controller advised that the airplane was identified on radar, the pilot did not respond. The controller observed the airplane turn and descend toward McClellan Airfield (MCC), Sacramento, California; no further communications were received.
Data showed that at 1459:17, fuel pressure began rising from about 40 to 43 psi. After reaching 6,492 ft mean sea level, the airplane pitched down 25° and banked left 36°. At 1459:24, torque and N1 were 64% and 95%, respectively, and began decreasing consistent with idle power. Oil pressure dropped from about 31 to 15 psi, fuel flow reduced from 46 to 16 gallons per hour, and interstage turbine temperature decreased from 1,118°F to 786°F.
At 1459:53, oil pressure increased to 28 psi and voltage began decreasing from 28 volts, consistent with the generator turning off. N1 stabilized near 65% and torque dropped to about 8%. At 1501:41, N1 decreased to 0, with simultaneous decreases in oil pressure and ITT. At 1502:00, the aircraft banked about 40° left, aligning with runway 16 at MCC.
During the last 38 seconds, the airplane lost about 425 ft while slowing from 125 to 89 knots. Torque and N1 were 0, and propeller rpm slowed from 1,746 to 948. The next data point showed airspeed 0 and discontinuities consistent with impact.
Witnesses saw the airplane flying south along 28th Street toward MCC at low altitude, then making a sharp right turn and disappearing into trees.
The pilot's family later reported hearing three radio transmissions; the second was indiscernible except the registration, and the third was the pilot acknowledging a controller's directions. No emergency was declared.
Wreckage and Impact
The accident site was in a residential backyard. Powerlines 190 ft north of the wreckage showed bends consistent with impact. The airplane came to rest upright on level terrain on a heading of about 100° magnetic, about 1.3 nautical miles from the approach end of runway 16 at MCC.
The airframe was relatively intact; cockpit sustained minor crush damage. The throttle was between mid- and full-throttle, propeller lever at feather, condition lever mid-range. The throttle quadrant retention clip was displaced, but it could not be determined if due to impact. The generator switch was on, the generator circuit breaker out, and the air conditioner switch on.
Fuel system examination: left and right fuel pumps selected to auto, center pump off. When the boost pump was activated, about 20 gallons of fluid was pumped from the header tank at about 70 gph, normal operation. The fuel control unit (FCU) had impact damage but functional testing revealed no anomalies. The mechanical fuel pump shaft was intact with no pre-impact abnormalities.
Engine examination: operational testing showed normal start, propeller cycled twice from fine to feather, and acceleration/deceleration behavior acceptable. No pre-impact mechanical malfunction was found.
Propeller examination: all blades rotated in unison when one was moved. No evidence of positive blade twisting normally seen with engine power at impact. Leading edges had abrasion but no impact damage. Geometric analysis indicated blades were at minimum flight angle (fine pitch, about 18°–20°), not feather (90°). The propeller lacked an internal feathering spring. The propeller governor was undamaged. The airplane was not equipped with an emergency electric propeller feathering pump; no requirement existed.
Data from the VR Avionics Turbine Starter Limiting/Monitoring System showed the pilot did not attempt an engine restart.
Medical and Pathological Information
The autopsy determined the cause of death as blunt force injuries. Atherosclerotic disease was noted, with up to 70% and 60% stenosis in the left anterior descending and right coronary arteries, respectively, and an area of fibrosis consistent with a remote myocardial infarction. These findings placed the pilot at some increased risk for a sudden cardiac event. Toxicology was negative for carbon monoxide and ethanol; positive for Atorvastatin and Pioglitazone.