Accident Summary
On March 6, 2009, at approximately 1453 eastern standard time, an experimental amateur-built Stewart S51, registered N551X, was destroyed when it struck trees and terrain in a recreational vehicle park in Ocala, Florida. The owner/pilot, the sole occupant, was fatally injured. The flight was conducted under 14 CFR Part 91 as a personal test flight. Visual meteorological conditions prevailed, and no flight plan was filed.
Aircraft and Pilot Information
The aircraft was a two-place, 70% scale replica of the North American P-51 fighter, of all-metal construction with retractable landing gear and electrically driven flaps. It was powered by a liquid-cooled, port-injection Chevrolet 612 cubic inch engine producing approximately 400 to 600 horsepower, driving a four-blade Hartzell constant speed propeller. The fuel system consisted of integral wing tanks with a total capacity of 68 gallons.
The pilot, aged 80, held an airline transport certificate with multi-engine land rating, commercial certificates for single-engine land, sea, rotorcraft, and glider, a flight instructor certificate, and an airframe and powerplant mechanic certificate. He had approximately 13,980 total flight hours, with only 0.3 hours in the accident aircraft, logged the day before the accident. His most recent flight review was completed in September 2007.
The aircraft kit was purchased by its first owner and completed by its second owner in 2002. The second owner flew it about 15 hours before selling it partially disassembled to the accident pilot in March 2003. A special airworthiness certificate was issued in July 2008, with operating limitations restricting flights within a 40-mile radius of the Ocala VOR.
Witness Accounts
Seventeen witnesses provided information. Most observed the airplane flying low and slow; nine reported the engine sputtering or making unusual sounds, and five, including a Florida Highway Patrol officer, saw that the engine was not operating. The airplane was seen descending, banking sharply to avoid a cell phone tower, then striking trees before impacting the ground between two unoccupied recreational vehicles. A fire ensued.
The pilot's widow stated that the pilot had reassembled the airplane at his home airstrip, and he described the first flight on the previous day as "absolutely perfect." She watched him take off for the accident flight at about 1435 to 1440.
A friend indicated the pilot had struggled with fuel leaks, which were eventually resolved. During taxi tests, the engine ran roughly and cut out on multiple occasions, apparently from fuel-related issues. The friend reported that after high-speed taxi tests, fuel filters or screens were found clogged.
Another S51 builder stated that the pilot used a sloshing sealant (PPG Aerospace PR-1005-L) to correct fuel leaks, which left a white oxide residue and had been known to cause problems in other kit aircraft. He noted that the pilot conducted at least two high-speed taxi tests, and both times the engine quit due to clogged filters.
Wreckage and Impact
The accident site was 11.3 miles south-southeast of Idle Wild Airport (FL63), the pilot's home field. The airplane impacted the ground between two unoccupied RVs, damaging them with debris. A fence separated the RV park from a wooded area to the south. The main wreckage lay about 60 feet north of the fence; a portion of the left wing was found 35 feet south of the fence, and the tailwheel was located approximately 225 feet south of the fence. A cell phone tower, about 500 feet tall, stood 475 feet south-southwest of the main wreckage, with no damage to the tower or its guy wires.
The aircraft, engine, and propeller sustained significant fire damage. The tailwheel was suspected to be in the extended position, but the main landing gear position could not be determined. Engine control positions were unascertainable.
Fuel System Issues
A partially used can of PPG Aerospace PR-1005-L slosh sealant was found in the pilot's hangar. This sealant conforms to MIL-S-4383C and is intended for integral fuel tanks as a topcoat. However, the S51 builder's guide specified the use of Pro-Seal (MIL-S-8802E or MIL-S-8784B) applied between components during assembly. The PR-1005-L sealant, which is applied after assembly, had been reported by other builders to flake off and clog fuel screens.
Examination of the wreckage revealed that the interior surfaces of the fuel bays were coated with a charred brown/black material consistent with fire-damaged coating. One in-tank fuel pickup finger screen was partially occluded by this material. The pre-accident condition of the screen could not be determined, nor could the condition of other screens.
Toxicology and Medical
An autopsy listed the cause of death as multiple blunt force injuries. Toxicological testing detected triamterene, a prescription diuretic for high blood pressure, in the blood and urine. Triamterene is generally approved by the FAA and not typically expected to cause impairment. The pilot did not list any medications or medical conditions on his most recent medical certificate application (March 2007).
Additional Information
No communications with air traffic control were identified, and no radar targets were associated with the accident flight. The pilot's logbook showed very little flying activity in the months before the accident: 0.7 hours in the previous 30 days, 1.3 hours in 60 days, and 3.5 hours in 90 days. The aircraft's construction and maintenance records were minimal. No direct witnesses to the application of the slosh sealant were located.