History of Flight
On August 28, 2020, at about 0902 eastern daylight time, an Aero Commander 500-S, registration N900DT, was destroyed when it impacted a building near Pembroke Park, Florida. The commercial pilot and airline transport pilot were fatally injured. The flight was conducted under 14 CFR Part 91 as a familiarization flight, with the right-seat pilot serving as pilot-in-command to familiarize the left-seat pilot with the airplane.
Before departure, maintenance personnel asked the pilot whether he wanted to fuel the airplane or have it towed to the fuel pump. The pilot responded that he planned to fuel at the intended destination, Miami-Opa Locka Executive Airport (OPF). Takeoff occurred about 0852, and the airplane proceeded southeast to the shore, then flew south-southwest just offshore. At about 0858, an occupant contacted the OPF air traffic control tower, advising that the airplane was inbound. The airplane climbed to 1,100 ft mean sea level (msl). At 0859:49, an occupant reported an “engine problem” and stated they would divert to North Perry Airport (HWO). The controller approved the frequency change. ADS-B data showed the airplane turned southwest and climbed to about 1,250 ft msl. A witness about 2.8 nautical miles east-southeast reported hearing engines accelerating and decelerating, followed by a popping sound. At 0900:47, the airplane turned west-northwest, then north-northwest until near the accident site. Witnesses on a golf course reported seeing the airplane flying westward with no engine sound; it banked left and descended. Another witness about 440 ft northeast heard no sound before impact, observing the right wing strike the building, then the airplane rotated left and fell to the parking lot. No ground injuries occurred.
Personnel Information
The right-seat pilot was the chief pilot for a Part 135 cargo operation and was tasked by his company to familiarize company pilots in the airplane. The left-seat pilot’s mobile phone contained no relevant personal data from the accident date, but did include internet searches related to airplane performance made five days before the accident and a video taken four days before, showing the accident airplane taxiing on an airport ramp. No anomalies were noted in the video.
Aircraft Information
The airplane was manufactured in 1969. Its fuel system comprised five interconnected synthetic rubber cells with a total usable capacity of 156 gallons, serviced through a single filler port on the right wing. Fuel quantity was measured by a single transmitter in the center cell and indicated on a panel-mounted gauge. An optional Fuel Low Level Warning System was not installed. The maintenance manual required checking fuel quantity system calibration whenever a calibration-affecting component was replaced and every 1,000 hours or annually. The most recent annual inspection, completed August 14, 2020, followed 14 CFR Part 43 Appendix D and the Aero Commander 500 S maintenance manual. Neither Appendix D nor the inspection form specified calibrating the fuel quantity indicating system. Maintenance records showed only one documented entry for work on the fuel quantity system: a 1,000-hour inspection of the transmitter on December 11, 1981, at 3,086.0 hours. The fuel quantity indicator, though not documented in records, had a manufacture date of January 31, 1983, indicating it was replaced about 37.5 years before the accident. The airplane had accumulated about 7,215 hours since the last documented transmitter work.
The pilot was reportedly advised by maintenance personnel to operate the engines with mixture controls full rich because both engines had been top overhauled in February 2019 and were still being broken in. As of the annual inspection, the engines had accrued 2 to 33 hours since cylinder work. The engine operator’s manual recommended cruise at 65% to 75% power during break-in but did not require full rich operation.
The airplane was last fueled with 51.4 gallons of 100 low-lead aviation fuel on August 19, 2020, at OPF. The fueling individual stated the request was a top-off and that the right-seat pilot checked the tank after fueling. ADS-B data indicated the airplane had flown about 3 hours 42 minutes on three flights since that fueling, excluding the accident flight. Fuel consumption calculations estimated between 105 and 141 gallons were used on those flights, leaving an uncertain amount for the accident flight. For the 10-minute accident flight, calculations estimated 8 to 10 gallons were required.
Wreckage and Impact Information
Examination of the accident site revealed an impact mark on the building consistent with a 35° right bank. The wreckage came to rest on the ground adjacent to the building. No fuel odor was detected, but oil leakage was noted. No evidence of fire was found. The fuselage front was fragmented; wings were attached but heavily damaged; both engines separated. The right main landing gear was down and locked. Flight controls remained attached with binding attributed to impact damage. The rudder trim tab was set near 0°; left elevator trim tab was between 0.5° and 0.75° trailing edge up, while the right was near 0°, indicating possible chain misalignment.
Cockpit examination showed the fuel quantity indicator connector broken, the indicator destroyed, and no needle slap mark. The flap selector was down; left flap visually extended between 10° and 15°. Left throttle was 3/4 forward, right throttle full forward. Left propeller control full forward; right propeller control bent. Both mixture controls full forward; left fuel boost pump on; left ignition selector on left magneto.
Fuel system examination found 5 ounces in left front tank, 11 ounces in left rear, 7 ounces in right rear. No fuel in right front or center tank; the right front bladder and center tank drain valve were impact damaged. No water in recovered fuel. Minimal leakage was noted.
The fuel quantity transmitter showed an open circuit between the wiper and resistor element, preventing operational testing. X-ray imaging revealed a fractured conductor in the wire between the wiper and connector pin C. Bypassing the fracture, resistive readings were normal. Visual examination showed no damage to wire insulation. A manufacturer representative stated that such a fracture could cause the fuel gauge to read extreme ends or respond erratically. NTSB Materials Laboratory examination found fatigue striations on some wire fracture surfaces, consistent with mechanical fatigue, and no ductile features. Both engines sustained extensive impact damage that precluded detailed examination.