Flight History
On March 11, 2011, at approximately 1207 central standard time, a Lancair model LC41-550FG, registration N521RT, sustained substantial damage during a forced landing after a loss of engine power while in cruise flight near Carbondale, Illinois. The pilot, who was the sole occupant, was not injured. The flight was operated under 14 CFR Part 91 on an instrument flight rules flight plan, with day visual meteorological conditions prevailing. The airplane departed Eagle Creek Airpark (EYE) in Indianapolis, Indiana, at 1049, destined for Poplar Bluff Municipal Airport (POF) in Poplar Bluff, Missouri.
During cruise, the pilot experienced a momentary power loss and alerted air traffic control, indicating he was diverting to Southern Illinois Airport (MDH). While executing emergency checklist items, both manifold and oil pressure dropped to zero. The pilot then heard a loud pop from the engine, observed oil spraying from the upper cowling, the propeller stopped rotating, and smoke entered the cockpit. Unable to reach MDH, the pilot executed a forced landing to a harvested agricultural field. During the landing roll, the right wing struck a utility pole, and the airplane impacted a ditch before coming to rest across a road in a nose-low attitude.
Pilot Information
The 28-year-old pilot held a private pilot certificate with single-engine land and instrument ratings, issued on February 28, 2010. His most recent third-class medical certificate was issued on April 21, 2009, with no limitations. He reported 192 hours total flight time, with 147 hours as pilot-in-command, including 74 hours in the same make and model. He had flown 11 hours in the previous 90 days and 5 hours in the previous 30 days. His most recent flight review was completed on June 24, 2010, in the accident airplane.
Aircraft Information
The accident airplane was a 2004 Lancair model LC41-550FG (serial number 41030), powered by a Continental Motors TSIO-550-C reciprocating engine (serial number 802677) producing 310 horsepower through a Hartzell three-blade constant-speed propeller. The airplane had a maximum takeoff weight of 3,600 pounds. It was issued a standard airworthiness certificate on October 8, 2004, and was purchased by Robertson Contractors, Inc. on March 3, 2010. Total airframe time at the accident was 501 hours. The last annual inspection was completed on March 1, 2010, at 260 hours. The last major engine maintenance occurred on January 1, 2008, at 215 hours, replacing the No. 5 cylinder due to low compression. The right turbine inlet temperature probe was replaced on April 27, 2010, at 353 hours. Maintenance records showed no unresolved airworthiness issues.
Meteorological Information
The nearest weather reporting station, Southern Illinois Airport (MDH), about 5 miles north of the accident site, reported at 1152: wind variable at 6 knots, visibility 10 miles, scattered clouds at 25,000 feet, temperature 10°C, dew point -1°C, and an altimeter setting of 30.19 inches of mercury.
Wreckage and Impact
All airframe structural and flight control components were located at the accident site. Three ground tracks matching the airplane's wheel spacing extended about 200 yards on a south-southwest heading to a ditch and an east-west road. Portions of the right wingtip were found near a utility pole about 55 yards north of the road. The main wreckage rested across the road in a nose-low attitude. The outboard half of the right wing was substantially damaged from the pole impact; the nose landing gear was bent aft, and the engine firewall sustained substantial damage. Flight control continuity was confirmed. The engine and cockpit displays (PFD and MFD) were sent to the manufacturer and NTSB for examination.
Engine Examination
Disassembly at the manufacturer's facility revealed that the No. 2 cylinder piston had fractured into pieces, recovered from the oil sump. The No. 2 exhaust valve had fractured at the junction of the head and stem, with both parts found in the sump. The combustion chamber and spark plugs of No. 2 showed mechanical damage consistent with piston fragmentation. The No. 1 cylinder exhaust valve head had a V-shaped chip missing, with a corresponding mark on the valve seat; the remainder of the No. 1 cylinder appeared undamaged. Metallurgical testing confirmed that the No. 2 exhaust valve fracture was a fatigue failure initiating from multiple sites, with heavy oxidation indicating prolonged exposure to combustion conditions. The valve head and welded zone met design specifications. The No. 1 cylinder head showed coking deposits consistent with elevated valve stem temperatures; the missing V-shaped area lacked discernible fracture morphology due to oxidation.
Flight Data Analysis
Data from the Avidyne PFD and MFD recorded the entire accident flight. The airplane departed at 1049, climbed to 10,000 feet mean sea level. For most of the flight, cylinder exhaust gas temperature (EGT) spread was about 290°F; No. 2 cylinder EGT was consistently about 135°F warmer than others. At 1 hour 18 minutes into the flight, No. 1 cylinder EGT increased by 130°F, while others rose less than 20°F. At 1156:03, engine speed, fuel flow, oil pressure, and manifold pressure began decreasing. Descent started at 1157:40, and the airplane landed at 1207:23. All recorded engine parameters remained within the airplane pilot operating handbook (POH) normal ranges. Review of earlier flights (from September 2010) showed similar EGT differences for No. 2 cylinder, but the No. 1 cylinder elevation was unique to the accident flight. The pilot reported operating the engine at full-rich for takeoff and climb, with cruise settings of 31 inches manifold pressure, 2,400 rpm, and fuel flow 22-24 gph.