What happened
On 13 May 2015, an Airbus A319-111, registration G-EZDN, was performing a commercial passenger flight from Glasgow to Bristol Airport. While the crew had originally prepared for an ILS approach to Runway 09, a change in wind direction and preceding traffic led them to request a visual approach to Runway 27.
To facilitate this, the commander disconnected the autopilot and autothrend, transitioning to a manual flight profile. During this maneuver, the commander turned the aircraft toward a point near the runway threshold. However, the crew failed to update their navigational range ring, which remained centered on the threshold of the previous runway. As the aircraft descended, the crew became increasingly disconnected from their intended flight path. The commander misidentified airfield lighting as the runway threshold and turned the aircraft onto an intercept heading that was significantly north of the centerline.
As the aircraft descended through 1,800 ft, the first officer noticed the aircraft was off-track. Despite the commander's reassurance, the first officer identified communication masts near the village of Dundry in an unexpected position, confirming they were not on the correct path. The aircraft had descended to an altitude of 1,200 ft, and the radio altimeter showed a minimum height of 488 ft agl as the aircraft crossed a ridgeline. Realizing the loss of positional awareness, the crew initiated a go-around and subsequently landed safely using an ILS approach.
The investigation
The investigation examined the flight's history, the crew's manual flight techniques, and recorded data from the aircraft's wireless quick access recorder and Bristol Airport's noise monitoring system. Investigators analyzed the crew's use of the navigation system, specifically the 5 nm range ring, and their adherence to noise abatement procedures. The investigation also reviewed the cockpit's operational state, noting that the go-around altitude was not set in the Flight Control Unit until after the maneuver had already begun.
Findings
- The crew implemented a significant change to their briefed approach without updating their internal briefing, which prevented the co-pilot from effectively monitoring the flight.
- The commander likely failed to update the 5 nm range ring to the new runway threshold, leading to a loss of situational awareness regarding their lateral position.
- The crew did not communicate their growing uncertainty regarding their position until the first officer requested a go-around.
- The failure to set the go-around altitude prior to the maneuver suggests the landing checklist was either incomplete or performed inadequately.