Plane struck power line before disappearing: TSB
A plane that went missing in June with a flight student and an instructor was flying too low and hit a power line, according to a report from the Transportation Safety Board of Canada.
Crews scoured the Fraser River in Maple Ridge on June 6 after a witness reported seeing a small plane flying low above the river before going into the water and disappearing from view.
The plane and its occupants haven't been found.
The TSB report, published Thursday, says the International Flight Centre Inc. Cessna 172M aircraft was conducting a training flight from Boundary Bay Airport with one student and one instructor on board.
Shortly after 1 p.m., the aircraft began a descent from 2,200 feet (660 metres), flying over the Fraser River near the Fort Langley water aerodrome.
The plane had levelled at 200 feet over the river when radar contact was lost at about 1:12 p.m.
A minute later, the aircraft flew into a power transmission line that was strung across the Fraser River, about 125 feet above the water, the report said.
Observers in the area reported seeing a low-flying aircraft, and then seeing a splash in the river. They then saw the aircraft partly submerged. The first 911 call was received at 1:19 p.m.
When emergency responders arrived, the aircraft could no longer be seen. Over the next several months, the RCMP used boats, helicopters, divers and underwater imaging equipment in an attempt to locate the aircraft.
However, the report says the water level in the river was high at the time of the crash, which hampered the first few months of the search.
At the time, Mounties said the flight plan submitted by the missing pilot didn't take the plane into the area where it was reportedly seen going into the water.
Authorities say the aircraft was equipped with an emergency locator transmitter, but no signal was detected.
According to the TSB report, the power transmission lines aren't considered an obstacle to air navigation.
However, in 2008, Transport Canada had determined the crossing to be an obstacle because of the proximity of the power lines to the flight route through the Glen Valley Area. As a result, lights were installed on the towers, and the power transmission lines were included on navigational charts for the area.
The report notes that at the time of the crash the lights hadn't been activated, but that the plane was at an increased risk because of its altitude.
“Intentionally flying at a low altitude increases the risk of an accident,” the report states, adding that when flying at heights under 300 feet, obstacles can be difficult to see as they might not be physically marked or indicated on navigational charts.
“Flying at low altitude also reduces the margin of safety in the event of engine failure, a loss of control or any other unexpected circumstances, and increases the risk of an impact with the ground or an obstacle.”
The report notes that while the flight training program outline provided to the student didn't contain a policy on acceptable minimum altitudes for low-level flying activity, the senior flight instructor had verbally directed his instructors to not go below 500 feet during flight instruction.