Incident Overview
A helicopter pilot reported that prior to beginning aerial application flights for the day, he calculated that approximately 490 pounds of chemical would bring the helicopter's weight near the manufacturer's maximum gross weight limitation. After completing an aerial application flight, he landed on a platform atop a chemical reloading truck and refilled the chemical tank with the pre-calculated amount.
Sequence of Events
Once the tank was reloaded, the pilot maintained a stabilized hover over the truck and transitioned to forward flight. As the helicopter cleared the truck, the engine made a lower sound, and the main rotor low revolutions per minute (RPM) horn activated along with the caution light. The pilot immediately added power, lowered the collective to restore main rotor RPM, and pitched forward to gain airspeed. However, the helicopter would not climb. He then decided to perform a roll-on landing on the adjacent field, but the helicopter landed hard.
Damage and Mechanical Status
The helicopter sustained substantial damage to the tail cone, tail rotor blades, and fuselage. The pilot reported no preaccident mechanical failures or malfunctions that would have precluded normal operation.
Weight and Balance Recalculation
After the accident, the pilot recalculated the helicopter's weight and balance. He determined that during the reloading operation, the chemical tank was not empty, with about 80 pounds of chemical remaining, and the added precalculated amount of chemical exceeded the maximum gross weight limitation.