What happened
On 2 March 2001, an Airbus A320-214, registration G-OOAR, was conducting a public transport charter flight from Lanzarote to Dublin. While descending through 4,200 feet approximately 18 nm south of Dublin Airport, the aircraft's Enhanced Ground Proximity Warning System (EGPWS) triggered a 'Terrain, Terrain - Whoop, Who 0up, Pull Up' alert.
In response to the warning, the flight crew executed a standard avoidance manoeuvre, applying full aft sidestick and maximum takeoff/go-around thrust. During this sudden pitch-up, a cabin crew member lost her balance in the aft galley and fell, resulting in a fractured collar bone. The aircraft subsequently landed safely at Dublin, where medical assistance was provided for the injured crew member.
The investigation
The investigation examined the circumstances surrounding the EGPWS activation and identified that the aircraft was flying at an indicated airspeed of approximately 298 knots. Although the aircraft was maintaining a safe altitude above the ground, the rapid change in terrain elevation caused the radio altimeter to detect a high rate of closure with the ground. Specifically, the system measured a peak closure rate of roughly 9,000 feet per minute, which fell within the activation envelope for EGPWS Mode 2A.
Investigators also noted a similar event involving another Airbus A320, G-OOAD, in the same geographic area just weeks later. The investigation highlighted that while the aircraft remained well above the required terrain separation, the combination of high airspeed and rapidly rising terrain was triggering nuisance alerts.
Findings
- The EGPWS alert was triggered by a high rate of terrain closure measured by the radio altimeter as the aircraft traversed rapidly rising terrain.
- The aircraft was operating at a high airspeed (298 kt) while descending through an area with significant topographical changes.
- At the time of the alert, the aircraft was still at a safe altitude of at least 1,700 feet above the local terrain.
- The injury to the cabin crew member was caused by the physical forces of the sudden avoidance manoeuvre.