History of Occurrence
On the evening of 23 June 2014, a Robinson R44 Raven II helicopter, registration YR-BKR, operated by S.C Becker Aviation Trans S.R.L, was performing avio-chemical flights near Slobozia, Giurgiu County. The helicopter, with only the pilot on board, landed at a farm to establish a working point. The pilot conducted two utility flights of about five minutes each, taking off in an east-west direction. Obstacles approximately 100 meters away prompted the pilot to choose a new take-off direction without close obstacles, but the area was covered with wheat crop about 1 meter high.
During the subsequent take-off, the helicopter used ground effect over 50-70 meters but reached only 10-12 meters altitude and could not exceed 20 knots. When the pilot attempted to increase speed to clear obstacles, a low rotor speed warning sounded. To prevent engine shutdown, the pilot lowered the collective pitch and turned left to pass below power lines. The helicopter suddenly lost altitude; the utility ramp and left landing gear skid contacted the vegetation, causing deceleration and a nose-down attitude. The pilot pulled back on the controls abruptly, causing the main rotor blades to strike and sever the tail boom. The helicopter then leaned left and impacted the ground. The pilot shut off electrical switches and exited without injury.
Damage
The helicopter sustained substantial damage: main rotor blades destroyed, tail boom sectioned, drive shaft and tail rotor control destroyed, tail rotor propeller damaged, and utility equipment damaged. No fire occurred.
Aircraft and Pilot Information
The helicopter was a Robinson R44 Raven II (MSN 12055, manufactured 2008), registered in Romania as YR-BKR. It was owned by SALAMANDRA FLY GMbH and operated by S.C Becker Aviation Trans S.R.L. The engine was a Lycoming IO-540-AE1A5 piston engine using Avgas 100. The aircraft was equipped with a liquid spraying system per STC SR01215CH, without a quantity indicator for the liquid tank. Total flight hours at the time were 775.
The pilot, a 36-year-old male, held a valid CPL(H) license and a Class 1/2 medical certificate. His total helicopter flight experience was 640 hours, including 390 hours on the R44.
Weather
At the time of the accident, the temperature was approximately 28°C, wind calm, and visibility greater than 10 km with clear sky. The meteorological conditions had no influence on the occurrence.
Conclusions and Probable Cause
The investigation commission noted that the flight field was chosen without prior risk assessment. The take-off site had obstacles including power lines, poles, and buildings. The pilot could not accurately measure the liquid amount in the utility tank, so gross weight was approximated. The pilot was pressed for time due to approaching sunset and did not adequately assess the work area.
The cause of the accident was the sudden loss of helicopter altitude during take-off and the hanging of the landing gear’s left skid in the overflown wheat crop. A contributing factor was the wrong choice of take-off heading towards an area with high vegetation, which prevented optimal helicopter acceleration during take-off in ground effect.