Accident Details
On July 14, 2009, about 0930 Alaska daylight time, an experimental amateur-built Zenair STOL CH701 airplane, registration N701BX, was destroyed in an uncontrolled descent during takeoff/initial climb from Kalmbach Lake, approximately 5 miles northwest of Wasilla, Alaska. The airplane was operated by the pilot as a visual flight rules (VFR) local flight under Title 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot and sole passenger received fatal injuries.
The passenger was an FAA inspector from Oklahoma City, Oklahoma, who was giving the pilot, an FAA designated pilot examiner (DPE), an annual proficiency checkride required to maintain his DPE certification.
A witness at the site reported coming upon the burning wreckage in the middle of a road and called 911. Another witness, familiar with the airplane, observed an unusually long takeoff roll but lost sight of the aircraft before it reached the end of the lake. No witnesses saw the actual impact.
Aircraft and Pilot Information
The 72-year-old pilot held an airline transport certificate with multi-engine land and single-engine land and sea ratings, along with flight instructor, flight engineer, ground instructor, and repairman experimental aircraft builder certificates. His most recent second-class medical certificate was issued June 6, 2008, with a corrective lenses limitation. No personal flight logbooks were found; a June 6, 2006 medical application indicated 27,200 hours of flying experience.
The accident airplane was an experimental amateur-built Zenair STOL CH 701/A, originally completed and registered in 1990. The pilot, who held a repairman certificate for experimental amateur-built aircraft, maintained the airplane. The last maintenance logbook entry on June 12, 2009, noted an engine overhaul and declared the airplane safe for flight, recording 529 total hours. The airplane had been placed on floats on September 19, 2006, with a weight and balance completed at that time.
Wreckage Examination
The accident site was in the center of a dirt road with steep banks and trees on both sides, about 300 feet from the southwest end of the departure lake. No evidence of striking trees or banks was found. All major components and control surfaces were present. A postcrash fire consumed most of the passenger cabin and inboard sections of each wing.
Float crush lines indicated a steep vertical descent, with the left float striking the ground first. The left wing had corresponding crush damage; the fuselage forward of the empennage was consumed by fire, with pooled molten aluminum. Both wings lay on the left side of the fuselage centerline. The tail section, including rudder, horizontal stabilizer, and elevators, was damaged but intact. Control cable continuity from ailerons, flaps, elevator, and rudder was confirmed to the burned cabin area.
The engine showed fractured cylinders and case, with melting from the fire. The composite three-bladed propeller had burned; pieces found in brush included a fragment 8-10 inches long with leading edge damage and fractures perpendicular to the leading edge. No evidence of preimpact mechanical problems was discovered.
Weight and Balance Considerations
A representative weight and balance was calculated by the investigator-in-charge. Pilot and passenger weights were derived from current FAA medical certificate information. The airplane had a 29-gallon fuel capacity; only 7.5 gallons (consistent with a one-hour checkride and 30-minute VFR fuel reserve) were used for the calculation. Empty weight, gross weight, and center of gravity (CG) limits were from the maintenance logbooks.
According to the airplane's official weight and balance, maximum gross weight on floats was 1100 pounds, with CG limits of 10 inches aft and 18 inches forward. Loaded as calculated, the airplane's gross weight was 1136 pounds, 36 pounds over the maximum, but CG was within limits at 17.08 inches. A witness reported that after the checkride, the pilot and passenger planned to fly to a remote lake for fishing, which would have required an additional 7.5 gallons of fuel and 45 pounds of weight, plus fishing and survival gear of unknown weight.
Medical and Toxicological Findings
A postmortem examination of the pilot attributed cause of death to blunt force injuries and thermal charring from the airplane accident. Toxicological testing by the FAA's Civil Aeromedical Institute was negative for alcohol or drugs but detected 28% carbon monoxide in the blood.
Witness reports of smoke, evidence at the site, and fire department response indicated the airplane burned intensely for 30-40 minutes.