What happened
On 19 November 2010, a Cessna 501 Citation, registration G-VUEM, was performing a cargo flight from Belfast Aldergrove to Birmingham Airport. The mission involved transporting a transplant organ. During the ILS approach to Runway 15, the aircraft encountered a sudden and unexpected bank of fog that had moved over the airfield.
As the aircraft descended, the co-pilot was flying manually after disconnecting the autopilot because it had failed to capture the localiser. While the crew had previously maintained visual references, the sudden loss of visibility caused the commander to become focused on searching for the runway lights. During this period, the aircraft descended below the Decision Altitude without the required 'decision' or 'go-around' call being made. The aircraft subsequently struck the glideslope antenna tower, causing a fire to break out on the left wing.
The aircraft slid across the grass, leaving a wreckage trail. The impact caused the left main landing gear to detach and the aircraft to come to rest on its belly. The co-pilot evacuated the cabin and sustained minor flash burns, while the commander was initially trapped in his seat due to the deformation of the instrument panel. He was eventually rescued by fire crews.
The investigation
The AAIB investigation examined the aircraft wreckage, radar data, and meteorological records. Investigators found that the aircraft's left wing fuel tank had ruptured upon impact, feeding a short-duration fire. The investigation also reviewed the cockpit procedures, noting that while the crew had performed standard altitude callouts, the critical decision-making call was omitted.
Meteorological analysis revealed that while the approach began in clear conditions, a sharp and rapid fog bank had moved into the area. Additionally, the investigation looked into the response of the Airport Rescue and Fire Fighting Service, noting that one fire appliance became bogged down in the soft, waterlogged ground because its differential locks had not been engaged before leaving the paved surface.
Findings
- The aircraft entered unexpected instrument meteorological conditions (IMC) late in the approach due to a rapidly moving fog bank.
- The absence of a 'decision' call led to the aircraft continuing its descent below minima without the crew initiating a go-around.
- The commander's attention was likely diverted by the sudden loss of visual references.
- The aircraft struck the glideslope antenna tower, which caused the subsequent fire and structural damage.
- The ground conditions were unusually soft due to higher-than-average recent rainfall.