History of Flight
On April 17, 2011, approximately 1615 central daylight time, a Claus Christen Eagle II experimental amateur-built airplane, registration N38RC, was substantially damaged when it impacted terrain near San Angelo, Texas. The commercial pilot and a pilot-rated passenger sustained fatal injuries. The airplane was co-registered to and operated by the pilot. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations Part 91. The flight departed San Angelo Regional Airport (SJT) around 1600.
According to local authorities and air traffic control data, the airplane departed SJT from runway 18 and executed a left turn to the east-northeast, then a turn to the northwest. Approximately 8 nautical miles northwest of SJT, radar data showed the airplane maneuvering at altitudes between 3,100 and 4,500 feet mean sea level for about 5 minutes before radar contact was lost. The last recorded radar target was at 2,400 feet msl. No communications were received after departure, and no witnesses were identified.
The airplane was reported missing on April 18 around 1300 after one occupant failed to report for duty at a local military base. A search located the wreckage at approximately 1530 by the U.S. Customs and Border Patrol.
Personnel Information
The pilot held a commercial pilot certificate with single-engine land and instrument airplane ratings. His most recent third-class medical certificate was issued on April 14, 2006, with no restrictions. According to his personal logbook, he had 606 total flight hours, with about 44 hours in the accident airplane. An aerobatic flight instructor reported that the pilot received 0.9 hours of dual aerobatic instruction in a Pitts S-2B in 2009; no additional aerobatic instruction was noted.
The passenger also held a commercial pilot certificate with single-engine land, multi-engine land, and instrument ratings. His most recent third-class medical certificate was issued on March 29, 2007, with no restrictions. No personal flight records were obtained; on his last medical application, he reported 177 hours of civilian flight experience.
Both individuals were United States Air Force cadets. The pilot occupied the rear seat, and the passenger the front seat; both were secured with 4-point restraint systems.
Aircraft Information
The accident airplane was an experimental amateur-built Claus Christen Eagle II, a tandem-seat bi-plane approved for aerobatic maneuvers. It was powered by a 200-horsepower Lycoming IO-360-A1A engine (serial L-14202-51A) with a two-bladed constant-speed metal propeller.
The airplane received a special airworthiness certificate on June 11, 1982, and was registered to the pilot and a co-owner on November 20, 2009. The most recent condition inspection was completed on March 5, 2011, at a total time of 829.1 hours. The engine was overhauled on March 9, 2010, and had accumulated 30.7 hours since overhaul at the time of the inspection.
Meteorological Information
At 1551, the SJT automated surface observing system reported wind from 190 degrees at 16 knots, gusting to 30 knots, sky clear, visibility 10 miles, temperature 32°C, dew point 8°C, and altimeter setting 29.72 inches of mercury.
Wreckage and Impact Information
The accident site was about 8 nm northwest of SJT in scrub oak terrain, at a GPS-measured elevation of approximately 2,100 feet msl. The main wreckage, consisting of fuselage, wings, and empennage, came to rest inverted roughly 30 feet from the initial impact point. The initial impact point contained separated sections of the propeller spinner. Debris was scattered within a 100-foot diameter.
Both upper and lower wings were deformed, crushed, and fragmented. Ailerons remained partially attached. The empennage was partially attached but was removed by rescue personnel before examination. Vertical and horizontal stabilizers were intact; elevator and rudder control surfaces remained attached. Flight control continuity could not be established due to damage, but no evidence of preimpact anomalies in control system hardware was found.
The cockpit was crushed and fragmented; the instrument panel destroyed. The airspeed indicator showed 195 knots, and the engine tachometer showed 2,000 RPM. Cockpit engine controls were in the full forward position.
The engine remained partially attached to the airframe. The propeller remained attached to the crankshaft, which was rotated by hand; mechanical continuity was noted throughout the engine, including cylinders and accessory gearbox. The throttle assembly was separated, but throttle and mixture linkage remained attached to their components. Fuel inlet and outlet connections were separated; fuel was noted in the fuel manifold valve. One propeller blade was twisted forward, the other aft.
No evidence of mechanical malfunctions or failures was noted during the examination.
Medical and Pathological Information
The Lubbock County Medical Examiner performed autopsies on both occupants. Toxicology specimens from the pilot were tested by the FAA Toxicology and Accident Research Laboratory. Results were negative for carbon monoxide, cyanide, and tested drugs. Ethanol was detected in blood, muscle, and urine; N-Butanol in blood; and N-Propanol in blood and urine. The report indicated ethanol was from sources other than ingestion. No toxicology specimens from the passenger were submitted.
Tests and Research
A portable Garmin GPSMAP 295 was found at the site. It was sent to the NTSB Vehicle Recorder Laboratory, but due to damage and fragmented internal components, no data could be recovered.
Additional Information
The Federal Aviation Administration defines aerobatic flight as an intentional maneuver involving an abrupt change in attitude, abnormal attitude, or abnormal acceleration not necessary for normal flight. FAA regulations (14 CFR Part 91) prohibit aerobatic flight below 1,500 feet above the surface. The Christen Flight Kit (page 5-3) warns against low-altitude aerobatic maneuvers and recommends safe altitudes for beginners of 5,000 feet agl and for competent pilots of 3,000 to 5,000 feet agl.
Probable Cause
No probable cause was determined in the source report.