Accident Summary
On March 10, 2016, at approximately 1533 mountain standard time, a Thomas Parkes Lancair ES, registration N44AZ, was substantially damaged following a forced landing at Ernest A. Love Field (PRC) in Prescott, Arizona. The pilot, who was the sole occupant and owner of the airplane, reported a partial loss of engine power shortly after takeoff. Visual meteorological conditions prevailed for the local flight, which was conducted under 14 CFR Part 91 without a flight plan. The flight was originating at the time of the accident.
Pilot Actions
According to the pilot, initial engine acceleration appeared normal as he advanced the throttle for takeoff, with manifold pressure set at 31 inches and normal turbocharger spool-up. After lifting off at about 75 to 80 knots, the acceleration tapered off as the airplane reached approximately 100 feet above ground level. The pilot reduced pitch attitude to maintain 80 knots but realized a power issue and advanced the throttle fully. He had sufficient runway to land but not enough to stop before a berm and a self-serve fueling station. He made a slight left turn to align with taxiway Charlie for a precautionary landing, but altered his approach to taxiway Bravo. Landing on the edge of the taxiway, the airplane ran out of ramp area and impacted rough terrain near taxiway Foxtrot. The airplane bounced, the nose gear collapsed, and it skidded across runway 12 before coming to rest upright in the grass. Damage included the nose landing gear, propeller, cowling, and firewall from striking a Precision Approach Path Indicator system's pipes, control boxes, and lights.
Postaccident Examination
A Federal Aviation Administration inspector found a compromised engine mount and firewall damage. On April 26, 2016, the NTSB investigator-in-charge (IIC) met with the pilot and performed a cursory engine inspection. The crankshaft rotated freely with no binding, and no catastrophic engine event was evident. The pilot attributed the issue to the turbocharger (serial number CCN00246). External examination of the turbocharger revealed hard scraping on the hot side, two chipped blades, two cracked blades, and a tight impeller. The pilot had purchased the engine in 1999 and installed the turbocharger, with its first flight in 2003; no historical records were available.
Turbocharger Analysis
The NTSB IIC sent the turbocharger to Hartzell Engine Technologies for detailed examination on May 5, 2016. On May 20, 2016, a Hartzell technician examined the component. The turbine wheel and blades showed signs of overtemperature (exhaust gas temperatures exceeding approximately 1,650°F) and possible overspeed. Reddish-white discoloration of the turbine wheel indicated excessive exhaust gas temperature, and shaft journal discoloration was consistent with excessive heat. The technician reported that high exhaust temperature and wheel speed caused blade material creep and diameter increase, leading to blade tip rub against the turbine housing. Blade tip failures resulted in rotating imbalance, damaging the compressor-bearing bore and introducing debris into the oil bearings. The technician concluded that imbalance and wheel rub likely caused the turbocharger to slow or stop, resulting in loss of boost and engine power.
The pilot noted that the airplane had an exhaust gas temperature gauge that would alert at 1,600°F, but no warning was observed during the accident sequence. The pilot also stated that the engine was later sent to a repair facility, which could not determine the cause of the overtemperature condition.