TSB report into helicopter crash at Edson airport warns of the dangers of trying to land in VRS conditions

Article content

A report into the May crash of a helicopter at the Edson airport cites the importance of approach planning and being aware of power management, particularly when conducting a downwind approach to a landing site.

On May 4, the Airbus Helicopters AS350 B2 helicopter was conducting a return flight to Edson Airport from a forest firefighting staging area when the crash occurred, according to a Transportation Safety Board of Canada report.

Article content

The pilot tried to avoid another plane that was attempting to land from the other direction and ended up flying into a Vortex Ring State (VRS), which caused him to crash, according to the report.

The pilot suffered minor injuries and was able to extract himself from the wreckage. The report noted the dangers of flying in VRS situations.

“Helicopters are susceptible to an aerodynamic phenomenon known as VRS. VRS occurs when a
helicopter’s flight path, airspeed, and rate of descent coincide with the helicopter’s downwash,” the report reads.

“In a fully developed VRS, the helicopter may experience un-commanded pitch and roll oscillations, and the rate of descent may approach 6000 fpm (feet per minute).”

The pilot of the AS350 B2 helicopter was approaching his landing at the airport when a flight of 4 Canadair CL-215T aircraft was approaching the runway from the opposite direction.

The pilot, not wanting to delay the group’s arrival, decided to approach the airport downwind and to the north of the runway, between the runway and the taxiway, with the intent of conducting a tight right turn to align the helicopter into the wind.

Article content

Just before entering the right turn toward the hangar, the helicopter began an uncontrolled descent from between 50 and 30 feet above ground level, before the aircraft struck the ground and rolled onto its right side.

The report stated that the helicopter struck the ground between the runway and the taxiway in a tail-low attitude, causing the tail rotor assembly to fracture. The helicopter then rotated to the right and struck the ground forcefully enough to break the right skid.

“Typically, a helicopter in VRS will lose considerable altitude before it is able to resume normal flight. If
insufficient altitude is available, the helicopter may impact the ground before it is able to recover from
VRS. Ideally, helicopters should be positioned into the wind for final approach to reduce the risk of
entering VRS,” read the report.

“Any potential time saved by attempting a downwind approach must be carefully weighed against the risks
that it may present.”

Related Stories

Share this article in your social network