What happened
On a scheduled flight from Vancouver to Victoria Harbour, British Columbia, a Helijet Airways S-76 carrying 11 passengers and 2 pilots diverted to Victoria airport due to weather conditions below landing limits. While performing an ILS/DME approach to runway 09 in foggy conditions, the crew initiated a missed approach procedure at the decision height.
During the transition to the climb, the pilot-flying unintentionally allowed the airspeed to drop to approximately 40 knots. When power was applied to begin the missed approach climb, the helicopter experienced a smooth but significant 100-degree turn to the right. This deviation went unnoticed by both pilots for roughly 30 seconds. The captain eventually identified the heading error and directed the pilot-flying to correct the course. Simultaneously, air traffic controllers provided radar vectors to maintain separation from another aircraft on the same approach.
The investigation
The investigation examined the flight profiles and crew experience. While the pilots were properly certified, they had rarely practiced ILS approaches at the low airspeeds (60 to 70 knots) used during this incident, as air traffic control requirements often necessitated much higher speeds. The investigation also looked into the aircraft's handling characteristics during the transition from a descent to a climb at low speeds.
Findings
- The pilot-flying experienced a loss of situational awareness due to unfamiliarity with the low-speed ILS approach profile.
- The aircraft's handling characteristics during the power application were unexpected, as the high rate of descent and low airspeed combined with significant torque-related forces caused the rightward turn.
- The turn was not immediately detected because the effects were masked by other attitude changes and a lack of external visual references.
- The captain's ability to detect the heading error was delayed by his focus on managing the missed approach and assisting the pilot-flying with instrument scanning.
- The pilot-flying lost situational awareness and unknowingly allowed the helicopter to turn 100 degrees away from the published missed approach procedure heading.
- The operator's training program had not previously included practice for ILS approaches at these lower airspeeds.
Safety action
Following the incident, Helijet Airways implemented several changes:
- The pilots involved underwent retraining and recertification.
- The company's training program was updated to include practicing ILS approaches at both high and low airspeeds.
- Standard operating procedures were modified to require a minimum airspeed of 75 knots during instrument approaches.
- An additional annual instrument training flight was introduced for all company pilots to focus on essential instrument scanning and aircraft handling techniques.