Introduction
On July 23, 2023, about 1420 eastern daylight time, a Bell 206-L4 helicopter, registered as N482TJ, sustained substantial damage in an accident near Caldwell, Ohio. The commercial pilot, operating under Title 14 Code of Federal Regulations Part 133 for Sky Aviation Corporation, received serious injuries. The helicopter had been housed at Cambridge Municipal Airport.
Pre-Accident Operations
A ground crewmember and the pilot arrived at the airport about 0710. The pilot conducted a preflight examination, and the crewmember took fuel samples from the helicopter and trailer fuel tanks, all described as "clean, clear, and bright." The helicopter and trailer were positioned at an off-airport landing zone (LZ2) for external load cargo drops. Operations began between 0800 and 0900, with the pilot completing eight cargo drops during the morning. The helicopter was refueled via hot fueling from the trailer tank as needed. No unusual observations were reported.
About 1215, the pilot returned to LZ2 and shut down the helicopter. A crewmember refueled it with 335 pounds of fuel. The pilot reported no issues with the helicopter and checked fluid levels, noting a known oil leak but adequate oil level.
Afternoon Flights and Accident
The helicopter departed LZ2 about 1330 for eight additional external load drops. Eight bags totaling 1,070 pounds were attached to eight release hooks on the external load carrier. The cargo release button on the cyclic control stick opened the respective hook; an emergency cargo release was found in the closed position. The maximum hook capacity was 2,000 pounds.
Flight track data showed the pilot maneuvering southeast of LZ2 for about 45 minutes. One bag weighing 130 pounds was dropped, leaving 940 pounds of external load. The helicopter then circled over the accident site before descending through trees in a near-vertical path and impacting terrain.
Pilot Memory and Witness Accounts
The pilot did not recall whether the second bag (also 130 pounds) was dropped, nor the descent and impact. He did not remember unusual helicopter sounds, annunciations, or weather issues. The ground crew did not witness the accident.
Structural and Systems Examination
The cockpit was substantially damaged by impact. The tailboom separated aft of the intercoastal support and rested near the fuselage; both horizontal stabilizers remained attached. Cyclic and collective controls on the pilot side fractured at the base but showed corresponding servo actuator movement. Control tube continuity was observed to all three servo actuators. Directional control continuity from tailboom to cockpit and tail rotor blades was established. No preimpact anomalies were found in main rotor or tail rotor drive systems.
The long line, measuring 122 feet, was partially wrapped around the main rotor mast and tangled in trees near the wreckage. The cargo hook and emergency release were found closed. When tested, the hook opened and the long line separated. The line exhibited tearing and abrasions about 14 feet below the cargo hook connection, consistent with wrap-around damage. All eight cargo hooks on the external load carrier were found closed; the second drop zone bag was located 20-30 feet from the main wreckage.
Engine and Rotor Examination
The engine remained installed, mostly undamaged except for bent/broken mount legs and a dented discharge tube. No leaks were detected. The N1 and N2 systems turned freely and were continuous. The compressor disassembly revealed rub marks between impeller and shroud, consistent with engine operation during the accident sequence. The oil filter was clean; oil appearance and smell were normal.
Both main rotor blades had significant fragmentation and leading-edge impact damage, with trailing edges split open. Trim tabs were located, but blade tip portions were missing. Both tail rotor blades remained installed without deformation or fragmentation; gearbox oil appeared normal. No mechanical anomalies were found that would have precluded normal operation.
Performance Study
The NTSB conducted an aircraft performance study to reconstruct the flight path and ground track. The estimated helicopter weight at the time of the accident was about 4,126 lbs. Performance data from the Rotorcraft Flight Manual indicated adequate hover out-of-ground-effect performance for the load and environmental conditions, assuming a skid height of 40 feet and gross weight of 4,550 lbs or less.