What aircraft was involved and where did it happen?

The accident on 2011-03-11 involved a Robinson R-44 II, at -, BE.

What was the probable cause of the accident?

The accident was caused by the helicopter operating at an altitude too low to clear the high-voltage ground wire.

Robinson R44 strikes high-voltage line near Bredene

A private helicopter flight in Belgium resulted in contact with a high-voltage power line, causing damage to the aircraft but no injuries.

What happened

On 11 March 2011, a Robinson R4/4 II, registered OO-PTA, was conducting a private leisure flight near Bredene, Belgium. The pilot, returning from training in the United Kingdom, had invited two passengers for a flight to capture aerial photographs. After departing from Zeebrugge, the helicopter flew at altitudes between 200 and 400 feet AGL.

While maneuvering near the Nukkerbrug, the helicopter performed a left turn at an altitude of approximately 133 feet. During this maneuver, the main rotor made contact with the ground wire of a 150 kV high-voltage power line. The impact severed the cable and caused fragments of the wire to puncture the aircraft's windscreen and cabin structure. Following the strike, the pilot performed a controlled descent and landed the aircraft safely near a power pole. All 3 persons on board escaped without injury.

The investigation

Investigators from the AAIU(Be) examined the wreckage and analyzed GPS data to reconstruct the flight path. The investigation confirmed that the helicopter was airworthy and the pilot held a valid license. The analysis focused on the proximity of the aircraft to the electrical infrastructure and the visibility of the lines.

Technical examination of the wreckage revealed that the main rotor blade had struck the ground wire approximately one meter from its tip. The investigation also noted that the pilot's flight preparation did not include a review of the Low-Air maps for the Bredene area, which would have identified the power lines. Furthermore, the investigation found that the sun's position contributed to the pilot's inability to visually detect the lines or the poles during the turn.

Findings

The Robinson R44 II was flying at an altitude of 133 feet, which was significantly below the height of the high-voltage ground wire (approximately 159 feet).
The low altitude of the flight was the primary cause of the accident.
The pilot did not notice the presence of the high-voltage lines due to the sun's orientation and the lack of specific obstacle awareness during the maneuver.