Accident Overview
On September 10, 2023, about 1345 Pacific daylight time, a Bell 212 helicopter, registered N873HL, was destroyed in an accident near Balch Camp, California. The pilot sustained serious injuries. The flight was operating under Title 14 Code of Federal Regulations Part 133 as a firefighting mission, under contract with the United States Forest Service.
Flight Details
The helicopter was equipped with a Simplex 304 Fire Attack System, consisting of a 375-gallon belly-mounted tank, a hover refill pump, and cockpit controls for water dispensing. The pilot reported completing eight water drops at altitudes between 6,000 and 7,000 ft msl before returning to Sanger, California, to refuel. During two water pickups earlier that day, the pump continued running after the snorkel was withdrawn but stopped when the switch was jostled.
At 1315, the pilot departed for Pine Flat Reservoir to pick up water at about 2,000 ft msl. While hovering over the reservoir and deploying the snorkel, he noticed water spilling from the tank. He disengaged the pump and activated the tank doors, but observed no movement. After climbing to about 20 ft above water, the doors moved when he cycled the tank power switch. He then successfully loaded water and proceeded to the fire area.
The fire was located between 7,000 and 8,000 ft msl, surrounded by 100-ft-tall pine trees. The pilot approached from higher terrain but noticed the helicopter required more power than expected. He decided to jettison the water load, but pressing the drop switch twice did not open the tank doors. As he turned toward a meadow, the low rotor rpm horn activated and the main rotor contacted a tree. The helicopter descended rapidly and impacted the ground, followed by a post-crash fire.
Load and Performance Calculations
Before the accident flight, the pilot completed a load calculation dated September 9, 2023, for an "initial attack fire" mission. The calculation referenced performance for Bell 212HP helicopters equipped with Boundary Layer Research FastFin (BLR FF), installed in 2018. Total calculated helicopter weight with equipment, personnel, and fuel was 8,642 lbs, with a jettisonable allowable payload for hovering out of ground effect (HOGE) of 1,858 lbs. The pilot listed the actual payload as 1,858 lbs.
The pilot estimated he had about 90-180 gallons of water onboard at the time of the accident. He estimated water quantity by observing engine torque, discontinuing water collection when torque reached 75% and 78%. No updated load calculation was performed for the accident drop.
NTSB calculations determined a base helicopter weight of 8,741 lbs without payload, based on an equipped weight of 7,141 lbs, crew 200 lbs, and fuel 1,400 lbs at water collection. Performance calculations at 2,000 ft pressure altitude and 30°C showed that at 75% torque the hover in ground effect (HIGE) weight was 9,965 lbs, and at 78% torque 10,280 lbs. Water payload at pickup was 1,224 lbs at 75% torque and 1,539 lbs at 78% torque. Operating weight at the accident site, at 8,000 ft and 20°C, with estimated fuel consumption of 120 lbs, would have been 9,845 lbs at 75% torque or 10,160 lbs at 78% torque. According to BLR FF HOGE charts, the weight limit at 8,000 ft and 20°C was 10,000 lbs.
Post-Accident Examination
The helicopter was destroyed by post-crash fire, consuming most of the airframe and components. The main drive shaft to the input quill was intact but thermally damaged, with circumferential scoring near splined ends. Main rotor blades showed no preimpact failure. The tail rotor drive shaft was mostly consumed; remaining portions confirmed continuity through the intermediate gearbox. Flight control continuity could not be established due to fragmentation and fire.
Both engines separated from the airframe and were examined at the manufacturer's facility with NTSB oversight. Neither engine exhibited evidence of a preimpact mechanical anomaly that would have precluded normal operation.
Historical maintenance records showed no abnormal performance of the Simplex fire attack system on the accident helicopter. The flight manual supplement for the system provided emergency jettison instructions: using the DOORS OPEN switch on the cyclic control box, holding for 3-5 seconds, and if doors fail to open, turning off the MASTER switch on the cockpit display box.