HENDRICKSON FLYING SERVICE INC: http://registry.faa.gov/N10009
FAA Flight Standards District Office: FAA Springfield FSDO-19
NTSB Identification: CEN16LA284
14 CFR Part 137: Agricultural
Accident occurred Monday, July 25, 2016 in Minonk, IL
Aircraft: TEXAS HELICOPTER CORP OH 13H/M74A, registration: N10009
Injuries: 1 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On July 25, 2016, about 1050 central daylight time, a Texas Helicopter Corp OH-13H/M74A, N10009, was substantially damaged during loading operations near Minonk, Illinois. The pilot was not injured. The helicopter was registered to and operated by Hendrickson Flying Service; Rochelle, Illinois, as a 14 Code of Federal Regulations Part 137 agricultural application flight. Visual meteorological conditions (VMC) prevailed and a visual flight rules (VFR) flight plan for the local flight had not been filed.
The westbound agricultural application nurse truck was stationary and parked on the right shoulder of a paved rural county road and was completely clear of the roadway surface. The helicopter was parked on the elevated helipad on top of the nurse truck with the helicopter's engine operating and the rotor blades turning. The nose of the helicopter was oriented to the north, and the helicopter's tail boom and the rotor disk then extended over the north edge of the east-west paved road.
While the loader was standing on top of the elevated helipad and reloading the helicopter's product tanks, a westbound 18-wheeler truck drove underneath the rotor disk and impacted the helicopter's tail boom. The impact resulted in the complete separation of the aft half of the tail boom and dislodged the helicopter from its position on the helipad. The helicopter remained upright and remained on the top of the helipad. The uninjured loader also remained standing on top of the helipad.
The driver of the 18-wheeler truck was not injured, but the right exhaust stack and the top right edge of the trailer showed damage which corresponded to the impact with the helicopter's tail boom.
The closest official weather reporting station was at KPNT, Pontiac, Illinois; located 17 miles east from the accident location, At 1055 the Automated Surface Observation System at KPNT, reported wind from 330 degrees at 4 knots, visibility 10 miles, clear skies, temperature 26 degrees Celsius (C), dew point 23 degrees C, with an altimeter setting of 30.02 inches of Mercury.