N11TGAnthony Mattioli AR-1 · 2020

On December 12, 2020, about 1523 eastern daylight time, an experimental amateur-built AR-1 gyroplane, N11TG, was substantially damaged when it was involved in an accident near San Mateo, Florida. The private pilot was fatally injured. The gyroplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

Automatic dependent surveillance broadcast (ADS-B) data showed the gyroplane departed Deland Municipal Airport – Sidney H. Taylor Field (DED), Deland, Florida, about 1350. The pilot performed two circuits in the traffic pattern before departing the traffic pattern around 1400. After departing the area, the pilot maneuvered north of DED remaining below 1,200 ft mean sea level (msl) for the remainder of the flight. At 1523:23, the ADS-B data ended about 1 nautical mile south of the accident site. The final 2 minutes of the data showed the gyroplane descending from 950 ft msl and 725 ft msl and its groundspeed increasing from 58 knots to 76 knots.

According to the kit manufacturer, the gyroplane’s “general cruise” speed was 47 to 86 knots (55 to 100 mph).

Concerned family members contacted the Federal Aviation Administration and an alert notice (ALNOT) was issued about 2130 for the missing gyroplane. It was located the following morning in a heavily wooded state forest with limited roads in the area.

A review of photographs taken by first responders revealed that the gyroplane came to rest in a densely wooded area on the left side of the fuselage The empennage remained attached to the fuselage. First responders reported that there was no odor of fuel at the accident site, and during recovery, they noted the fuel tank remained intact and contained an undetermined amount of fuel. There was no evidence of fire at the accident site.

Examination of the airframe confirmed continuity from the controls in the cockpit to the main rotor and the rudder. The empennage was separated from the fuselage during the recovery and the left side of the empennage was impact-separated. The main rotor remained attached to the fuselage and one of the blade tips was impact-separated and located in the vicinity of the main wreckage. In addition, chordwise scratching was noted on the blades. The two droop stops for the two main rotor blades were bent in a downward direction. There were no anomalies with the airframe that would have precluded normal operation.

The engine remained attached to the fuselage. The carburetor float bowls were removed and examined. The left carburetor float bowl had yellow fuel in it and no anomalies noted with the floats. The right carburetor float bowl contained yellow fuel with a brown, crusty substance in it. The fuel from both float bowls was tested with water finding paste; water was noted in the right carburetor float bowl, but not the left carburetor float bowl. Fuel was drained from the fuel tank sump and no water was noted when tested with water finding paste. Oil was noted in the lubrication system and coolant was noted in the cooling system. The engine was started using the ignition system and remaining fuel in the fuel tank. The engine ran up to full powerwith no anomalies noted.

The propeller blade remained attached to the engine. One of the three propeller blades was impact separated from about midspan. The other two blades remained attached to the hub, were undamaged, and did not display chordwise scratching.

An iFly GPS and an MGL Avionics Stratomaster Xtreme were retained for data download. Both devices turned on when power was applied, however neither device contained data.

The turbo control unit was downloaded at the engine manufacturing facility under NTSB supervision. The device recorded up to eight parameters and had a sample rate of about once a minute. The device would overwrite itself after an unspecified amount of time, but for the accident flight it recorded the parameters beginning at 27:24 and ending at 27:41, indicating that the engine had a total of 27:41 hours of operation time. Starting at 27:24, the engine rpm was 4,724 and the throttle position was at 52%. At 27:25, the engine rpm went to 5,305 and the throttle position was 100%. From 27:26 through 27:41, the engine rpm remained between 4,518 and 4,804 with the throttle position between 47% and 50%. Then, the next data point at 27:41, at unknown seconds, the engine rpm decreased to 418 and the throttle position went to 92%. The final data was recorded again at 27:41, with the engine rpm at 1113 and the throttle position was at 92%. In addition to the reduction in rpm, over the final three data points the airbox temperature dropped from 29°C to 24°C.