What aircraft was involved and where did it happen?

The accident on 2007-07-26 involved a MCDONNELL DOUGLAS HELICOPTER SYSTEMS 500N, registration HB-XYP, at Eglisau, ZH, CH.

What was the probable cause of the accident?

The accident was caused by the helicopter striking power lines during low-altitude filming, exacerbated by a lack of prior reconnaissance and an inadequate hazard analysis of the modified flight path.

MD 500N Helicopter Strikes Power Lines During Film Mission

An MD 500N helicopter collided with high-voltage cables at low altitude near Eglisau, Switzerland, resulting in a forced landing and local power outages.

What happened

On July 26, 2007, at approximately 08:54 AM, an MD 500N helicopter, registration HB-XYP, was conducting aerial filming operations near Eglisau, Switzerland. The mission, operated by Fuchs Helikopter AG, involved capturing high-definition landscape footage for a private production. While flying at a very low altitude over the Rhine river, the aircraft struck two high-voltage power lines at approximately 18 meters above the ground.

The impact caused significant damage to the aircraft and severed the cables, leading to a power outage in the Eglisau area lasting about thirty minutes. Despite the collision and subsequent engine warnings, the pilot managed to perform an emergency landing in a field on the northern bank of the river. There were no injuries to the pilot or the passengers on board.

The investigation

An investigation by the Swiss Transportation Safety Investigation Board (SUST) examined the flight preparations, the crew's decision-making, and the technical aspects of the aircraft. The inquiry reviewed flight logs, GPS data, and FLARM obstacle warning data. Investigators also analyzed the film footage captured during the flight, which provided a perspective of the visibility of the obstacles.

The investigation looked into the flight path changes made during the mission. While the initial flight plan was established, the crew made spontaneous deviations to take advantage of lighting conditions. The investigation also evaluated the effectiveness of the onboard FLARM obstacle warning system and the accuracy of the aeronautical charts used by the crew.

Findings

The primary cause of the accident was the collision with two power cables at 18 meters altitude.
The crew failed to perform a prior reconnaissance flight to identify low-level obstacles in the new flight path.
The risk analysis regarding potential hazards was insufficient, particularly when deviating from the planned route.
The pilot and director maintained an overly optimistic view of the visibility of power lines against the dark, wooded background of the riverbanks.
The crew relied on a FLARM warning device that contained an outdated database.
The pilot was unaware that the aeronautical charts in use did not depict obstacles located below 25 meters above the ground.
The director's influence on the pilot's decision-making contributed to the decision to fly beneath known obstacles and into unverified terrain.