What happened
During an instrument landing system (ILS) approach to runway 2lar in St. John's, Newfoundland, the crew of a Super Puma helicopter realized just before touchdown that the landing gear remained in the retracted position. As the pilots attempted to transition into a hover to correct the error, the nose of the Super Puma struck the runway surface. The aircraft was able to establish a hover, at which point the gear was lowered, and the helicopter completed the landing without further incident. There were no injuries to the two crew members or 11 passengers, though the aircraft sustained damage to the fuselage structure and two communication antennae.
The investigation
The investigation established that the flight was part of a demanding schedule involving a mission to the Hibernia oil platform. Due to deteriorating weather, the crew had experienced delays and was operating in a time-restricted environment. During the approach, the crew engaged in a complex radio exchange with Gander Area Control Centre regarding their intentions for a missed approach, which served as a significant distraction.
Furthermore, the crew maintained a higher approach speed than usual to maintain separation from following traffic. This caused the automated flight control system to initially overshoot the glidepath, requiring the pilots to perform several power adjustments to stabilize the descent. While the landing gear warning system was found to be fully functional, the investigation noted that the aural warning tones for the radar altimeter and the landing gear were very similar in frequency, making them difficult to distinguish when activated in close succession.
Findings
- The crew intentionally delayed the pre-landing check due to the high-workload environment and the need to manage the approach speed and radio communications.
- The crew failed to recognize the landing gear warning because the simultaneous or near-simultaneous activation of the radar altimeter warning led them to misinterpret the alert as a routine, non-critical advisory.
- The captain's focus on the visual landing maneuver in low-visibility conditions likely prevented the recognition of visual warning lights in his peripheral vision.
Safety action
- The operator has updated procedures to require the pre-landing check to be completed at 10 miles from the landing site to avoid interference with higher-priority tasks.
- A new "final landing check," performed silently by the non-flying pilot, has been implemented to verify gear, lights, and instruments.
- The company is investigating modifications to the aircraft's warning systems to ensure the landing gear and radar altimeter tones are more distinct.