NTSB Factual Report

On December 23, 2017, about 1415 central standard time, a X-Air LLC XA85 single-engine airplane, N20XA, collided with power lines while maneuvering at a low altitude near Oskaloosa, Iowa. The private pilot was fatally injured, and the airplane sustained substantial damage. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Day visual meteorological conditions prevailed for the personal flight that departed Oskaloosa Municipal Airport (OOA) about 1345 with the intended destination of Marshalltown Municipal Airport (MIW), Marshalltown, Iowa.

There were several witnesses who reported seeing an airplane flying at a low altitude in the general area of Oskaloosa, Iowa. One witness, who was driving south on Highway 63, reported seeing an airplane flying westbound at a low altitude near 210th Street. The location of the witness was about 1/2 mile east of the accident site. There were no witnesses to the final portion of the flight.

A preliminary review of available Federal Aviation Administration (FAA) air traffic control (ATC) radar data revealed no transponder data associated with the flight. Further review of available radar data did not reveal any primary track data that could be conclusively associated with the flight. The lower limit of ATC radar coverage at the accident site was about 2,000 ft above ground level (agl).

The accident site was in an open agricultural field. The initial impact was with a power line located about 35 ft above the ground. The damage to the airplane was consistent with it impacting the ground in a nose-down pitch attitude on a south heading. The airplane subsequently came to rest inverted about 230 ft from the initial impact with the power line. The main wreckage consisted of the entire airplane. A 80 ft section of steel-braided power line was found wrapped around the main landing gear. The nose gear had separated from the airframe. All major structural components and flight controls were identified at the accident site. Flight control continuity was confirmed at the accident site. The wing flaps were found fully retracted. First responders reported that they turned the electric master switch from ON to OFF. The electric fuel pump switch was in the ON position. Both electronic ignition switches were in the ON position. The starting fuel control was in the OFF position. The carburetor heat control was in the OFF position. The cabin heat control was in the ON position. The altimeter's Kollsman window was centered on 30.24 inches of mercury. The communication radio was turned-on, and the active frequency was set to the common traffic advisory frequency (122.8 MHz) for the departure airport. First responders reported that they observed fuel leaking from the estimated half-full fuselage tank. The fuel tank was subsequently removed from the fuselage. The fuel selector was found in the ON position. The engine remained attached to the fuselage through its engine mounts. An external examination of the engine did not reveal any damage. The two-blade, carbon-composite propeller was fragmented. The damaged propeller was removed from the engine to facilitate an operational engine test run. The engine, a 85-horsepower Jabiru 2200J, serial number 22J795, started and ran at various engine speeds without any hesitation or anomalies. The postaccident airframe examination and operational engine test run revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

The airplane was equipped with a Dynon EMS-D10 electronic engine monitor. The undamaged device was removed from the instrument panel and its non-volatile data was downloaded. A review of the recovered engine parameter data revealed consistent readings throughout the approximately 36 minute flight and no anomalies with engine operation. According to the engine parameter data, recorded at 10-second intervals, the engine was operating at a typical cruise power setting (2,850 rpm) before it experienced a sudden decrease of engine speed and oil pressure, consistent with an impact with a power line and terrain.

The airplane was equipped with a Garmin GPSmap 396. The GPS device was normally installed in a cradle located on the right-side of the instrument panel. The GPS device was recovered outside of the airplane cabin with no apparent damage. The device had separated from its antenna coaxial cable and external power supply during the impact sequence. The device was powered-on using its battery, and its non-volatile track data was downloaded. A review of the downloaded data established that the last recorded flight was on December 16, 2017, from MIW to OOA. There was no track data recorded on the day of the accident. Further examination of the last recorded map position, alerts, and calendar/clock established that the GPS device was not powered-on during the accident flight. A review of the device settings revealed that it was configured to automatically power-on when an external power source was detected and to automatically record the airplane's flight path. The GPS device normally received power through the airplane's electrical system, and was protected by a 3-ampere, fast-acting fuse installed on the primary buss. A postaccident examination of the fuse associated with the GPS external power supply revealed that it had blown. However, the GPS battery remained installed and was capable of powering-on the device when the power button was depressed.

A postaccident review of available meteorological data established that day visual meteorological conditions prevailed at the accident site. The nearest aviation weather reporting station was located at OOA about 12 miles southeast of the accident site. At 1415, the OOA automated surface observing system reported: wind 350° at 9 knots, a clear sky, 10 miles surface visibility, temperature -6°C, dew point -11°C, and an altimeter setting of 30.24 inches of mercury.