What happened
The accident occurred during the initial phase of flight immediately following a refueling or servicing event. The pilot was preparing for an agricultural spraying operation and had positioned the helicopter near a truck platform to transfer chemical spray into the onboard hopper. Once the transfer was complete, the pilot initiated takeoff procedures.
However, the hose used to pump the chemical into the hopper had not been disconnected from the aircraft or the ground rig. As the helicopter attempted to lift off, it remained tethered to the truck platform by the unremoved line. The continued application of collective pitch by the pilot to gain altitude placed excessive tension on the hose. This physical constraint prevented normal ascent and caused the helicopter to roll over onto its side.
The investigation
Examination of the scene confirmed that the chemical transfer hose was still attached to the helicopter's hopper inlet at the time of the accident. The connection had not been severed or detached prior to the initiation of the takeoff roll. The physical tethering force exerted by the stationary truck platform directly contributed to the loss of control and subsequent rollover.
Findings
The primary factor leading to this incident was the failure to disconnect the chemical application hose before attempting flight. This procedural error resulted in the aircraft being physically restrained during a critical phase of operation. The pilot's attempt to overcome this restraint through increased collective pitch exacerbated the situation, leading to the rollover.
Safety message
This incident highlights the critical importance of pre-flight checks and equipment disconnection procedures when servicing agricultural aircraft. Operators must ensure that all ground support connections, including fuel lines and chemical hoses, are fully detached and secured before initiating takeoff to prevent tethering accidents.