Accident Sequence
On November 22, 2022, at 1157 eastern standard time, a Robinson Helicopter R44, registration N7094J, sustained substantial damage when it impacted terrain in Charlotte, North Carolina. The commercial pilot and one passenger were fatally injured. The flight was conducted as a Title 14 Code of Federal Regulations Part 91 aerial observation flight to provide video training for a WBTV staff meteorologist over a simulated news scene.
Radar, automatic dependent surveillance-broadcast (ADS-B) data, and surveillance video indicated that the helicopter departed the WBTV heliport at 1150 and proceeded southbound for about 5 minutes until it was over Interstate 77 (I-77). The pilot then initiated a series of left 360° turns over I-77. During the third turn, the helicopter entered a rapid descent and impacted a grassy area adjacent to the southbound lanes of I-77.
The pilot was in contact with Charlotte (CLT) air traffic control tower at the time; however, a review of communication recordings did not reveal any calls of distress. Recordings on the local helicopter common frequency (123.025 MHz) included the pilot appearing to call out, “Three’s going down Sky Three’s going down” before impact.
Several witnesses provided statements. One witness reported a strange sound from the rotors before the accident, followed by a quick left pitch change and then a more severe left pitch change greater than a 45° left roll. The helicopter then descended abruptly behind trees and impacted the ground. Another witness observed the helicopter circling and, during the second or third turn, it “turned sideways 90 degrees” and then rapidly descended.
Maintenance History
The most recent maintenance recorded on the helicopter was on October 21, 2022, at 13,541.1 hours total aircraft time, when a damaged main rotor pitch link was replaced on blade “A.” The most recent inspection was a 100/300-hour annual inspection completed on October 16, 2022. A field overhaul was completed on August 15, 2019, during which the Lycoming O-540-F1B5 engine was replaced.
Company records showed the helicopter was operated on 26 flights, including the accident flight, after the October 16, 2022 inspection, all with the accident pilot at the controls. The operator’s Director of Maintenance confirmed that the forward left control rod end to the stationary swashplate (Robinson Helicopter Company part number D 173-1), along with the other two adjacent upper rod ends, were replaced during the field overhaul of August 15, 2019. The lower rod ends were also replaced during that overhaul. Inspection of the attaching hardware of these rod ends was required during each preflight inspection and during the most recent 100-hour inspection.
Wreckage Examination
The helicopter came to rest about 20 ft from the point of initial impact, oriented on a heading of 015°. There was no postaccident fire. Fractured portions of the landing gear were found within the initial impact crater. All primary structural components and rotor blades were located within the main wreckage.
The cabin area was completely collapsed downward with flat upward crushing of the entire lower fuselage. The rotor, transmission, and rotor mast were attached to the airframe but displaced forward 90°, rotated about the base of the transmission. The transmission/rotor mast assembly remained intact. The pilot and copilot seats and their supports were collapsed downward. The cockpit instrument panel was detached but remained in the forward cabin area. The tail boom was attached to the aft airframe structure and extended 7 ft to a separation at the aft section of tail boom bay 4. The separated section of tail boom (approximately 6 ft) had the vertical and horizontal stabilizers, tail rotor gear box, and tail rotor assembly attached.
Both main and auxiliary fuel tanks separated from the fuselage; both tanks had bladders installed, contained some fuel, and fuel caps were in place. The engine remained within the engine compartment but mounts were fractured; the engine was restrained by drive belts. The drive sheave and fan were attached with associated baffling in place. The four drive belts were present but had shifted off their grooves on the sheave. The engine starter ring had cut into metal baffling.
Examination of the Lycoming O-540-F1B5 engine found that compression and suction were observed on all 6 cylinders. Upper spark plug electrodes and lower spark plugs from cylinders 2, 4, and 6 were light gray with no mechanical damage. Lower spark plugs from cylinders 1, 3, and 5 were oil-soaked with no mechanical damage. The oil sump suction screen was clear. Fuel was observed in the carburetor bowl and the carburetor finger screen was clear. The gascolator contained fuel and tested negative for water. The left magneto sparked when turned by hand; the right magneto was impact damaged. The oil filter was cut open with no metallic particles identified.
Further examination of the transmission, main rotor drive, main rotor, and tail rotor did not reveal evidence of a mechanical malfunction or anomaly that would have prevented normal operation.
Cyclic and collective control continuity was established from the cockpit aft to the stationary swashplate through multiple breaks in the control tubes. All bell cranks and control tube rod end connections were present except for the upper forward left control rod to the swashplate flange. The forward left control rod end connection to the stationary swashplate flange was not connected, and the fastening hardware (threaded bolt, nut, palnut, two washers, and two hat-shaped spacers) was missing. The rotating swashplate had witness marks on the forward rotating face and underside in line with the forward left control tube rod end. The control tube rod end had witness marks on its outer diameter, the palnut was not present, and the rod end was extended (unscrewed) ¾-inch from the control rod. The upper forward portion of the rotor mast fairing and control rod had damage consistent with the control rod repeatedly impacting the interior of the fairing.
The stationary swashplate with attached pitch change link and yoke assemblies, main rotor blade pitch horn piece, and two forward upper flight control tube assemblies were forwarded to the NTSB Materials Laboratory for examination. Bolt thread contact marks were observed on the end fitting bearing outer race, bolt thread wear marks in the swashplate lug bore hole, and rubbing contact damage on the contact face of the swashplate lug. Witness marks on the lug and rod end were consistent with one of the two hat-shaped spacers being installed backwards.
Examination of maintenance records revealed that Robinson Helicopter Company Service Letter (SL) 50 had not been complied with. SL 50 instructed operators to replace certain cadmium-plated nuts (MS21042L4) with D210-series nuts due to corrosion and cracking issues. The D-210-series nuts should have been replaced during the field overhaul in August 2019 (a complete set was included in the overhaul kit). A mixture of MS21042L4 and D-210 nuts was found throughout the flight controls on the accident helicopter. The type of nut that liberated from the forward left control rod/stationary swashplate could not be determined.
Medical Information
According to the autopsy report from the Mecklenburg County, North Carolina, Medical Examiners’ Office, the cause of death of the pilot was blunt force injuries due to the helicopter crash.
Toxicology testing by the FAA Forensic Sciences Laboratory detected tramadol in the pilot’s urine at 19,593 nanograms per milliliter (ng/mL) and in liver tissue. Tramadol’s metabolites, o-desmethyltramadol and n-desmethyltramadol, were detected in urine at 5,199 ng/mL and 3,737 ng/mL, respectively; both metabolites were also detected in liver tissue. Quinine was detected in the pilot’s urine and liver tissue. No blood specimens were available for analysis.
During the pilot’s most recent FAA medical examination on June 30, 2022, he reported taking no medications and a history of hay fever. His personal medical records revealed that the pilot was prescribed methotrexate, an injectable biologic, prednisone, and tramadol by a rheumatologist as part of a treatment plan for psoriatic arthritis and polyarthralgia.