FTW93FA192

An air ambulance helicopter impacted high tension power lines while on initial takeoff climb from the median of an interstate highway after picking up one patient who had been involved in an automobile accident. The weather was reported as 500 feet overcast with 4 miles visibility in fog and rain showers. The pilot stated that he did not see the four unmarked high tension wires prior to executing his takeoff

History of flight

On June 20, 1993, at approximately 1742 central daylight time, a Bell 206L 3 helicopter, N911MT, was substantially damaged upon impact with power lines and the ground near West Monroe, Louisiana, while on initial takeoff climb. The helicopter was owned and operated by Metro Ambulance of Monroe, Louisiana, a 14 CFR Part 135 on demand air taxi operator. The airline transport pilot, the emergency medical technician, and the litter patient, sustained minor injuries. Instrument meteorological conditions prevailed at the time of the accident.

According to the operator, the helicopter was dispatched to the site of a single vehicle automobile accident to transport one of the occupants of the automobile who was complaining of having difficulty breathing. The medical technician aboard the helicopter stated that the pilot circled south of the accident site to clear the area as soon as the landing zone was identified. A normal approach was completed to the flares outlining the landing area on the median of the highway.

Witnesses at the site reported that after the patient was secured in the aircraft, the helicopter was brought to a hover with a pedal turn to align the aircraft for an east departure. As the helicopter initiated its takeoff climb, the main rotor blades impacted four unmarked power lines that crossed the highway from north to south at approximately 45 feet above the highway. After cutting all four wires, the helicopter landed hard on the shoulder of the road, collapsed the right landing gear skid, and slid for 45 feet before coming to rest.

In the enclosed pilot operator report, the pilot stated that he could see a set of power lines in front of him prior to lift off. Those wires were covered with a large black insulation material and contrasted against the gray overcast. He added that he did not see the smaller set of gray power lines close to the helicopter. Upon recognizing the power lines during the initial takeoff climb, he elected to attempt to fly under the wires, and the wires impacted the rotor blades and main rotor mast.

The nearest weather observation facility reported 500 feet overcast and 4 miles visibility in fog and rain showers.

Aircraft information

The helicopter was equipped with a wire strike protection system. A review of the helicopter and engine historical records by the Federal Aviation Administration inspector, did not reveal any anomalies or uncorrected maintenance defects prior to the flight. Weight and balance calculations were performed using figures provided by the operator. The helicopter was found to be within its limits at the time of the accident. No mechanical malfunctions were listed on the enclosed accident report submitted by the pilot.

Wreckage and impact information

The wreckage was scattered in a linear pattern paralleling the left shoulder of the eastbound lane of the interstate highway on a measured heading of 100 degrees. The four power lines impacted by the helicopter were suspended approximately 33 feet above the ground, approximately 431 feet from the point of takeoff. There were three high voltage lines and one shield line. All helicopter components and wreckage was located within 110 feet from the point of initial impact. The helicopter came to rest on a measured heading of 125 degrees.

Additional data

The wreckage was released to the owners at the accident site on June 21, 1993, upon completion of the field investigation.