What happened
On a daylight courier flight from Moncton, New Brunswick, to Sydney, Nova Scotia, a Swearingen SA-226, registration C-GTMW, operating as Speedair 703, performed an unstable approach that nearly resulted in a collision. While being radar vectored for an instrument landing system (ILS) approach to runway 19, the aircraft intercepted the localizer at a high speed of approximately 290 knots and a steep descent rate exceeding 4,000 feet per minute.
During the maneuver, the aircraft flew through the localizer at an angle of 98 degrees from the final approach course. Radar data indicated the aircraft descended to an altitude of 200 feet above sea level, significantly below the minimum descent altitude. Witnesses on the ground reported that the aircraft passed within 50 feet of the Lingan power generating plant. Following the overshoot, the crew received clearance for a new approach and landed at Sydney Airport without further incident. There were no injuries to the two crew members.
The investigation
The investigation examined the flight path, crew coordination, and air traffic control procedures. Investigators found that the crew had failed to maintain a stabilized approach and had lost situational awareness. A significant error was identified regarding altimeter settings: the pilot flying had updated the altimeter to the correct setting of 29.96 but failed to communicate this change to the pilot not flying, who continued to use an incorrect setting of 29.74. This discrepancy caused the co-pilot's altimeter to read 220 feet higher than the actual altitude.
Furthermore, the investigation looked into the Moncton Area Control Centre (ACC) controller's actions. It was determined that the radar vectors provided did not meet the required standards for intercepting the final approach course and that the controller failed to issue a safety alert despite the developing risk.
Findings
- The crew failed to properly plan and execute the approach, leading to an unstabilized approach.
- The flight crew exhibited a complacent attitude and a loss of situational awareness.
- The aircraft's speed and descent rate exceeded safe operational requirements.
- The controller did not comply with the radar vectoring procedures specified in the Air Traffic Control Manual of Operations.
- The crew's coordination was hindered by a lack of standardized operating procedures (SOPs) and the failure to communicate altimeter changes.