What happened
On 25 March 2019, a Boeing 737-800, registration G-TAWA, was operating a scheduled international flight from London Gatwick to Lanzarote Airport. The aircraft was performing a VOR A approach to runway 2/1 with 181 passengers and 7 crew members on board.
During the approach, the flight crew began descending through 3,648 feet. As the aircraft progressed along the approach, the crew manually adjusted the altitude settings on the Mode Control Panel (MCP) in increments, selecting 2,100 feet, then 1,400 feet, and finally 1,000 feet. During this descent, the aircraft's altitude dropped below the required minimums for the specific flight segment.
At 13:47:27 local time, while the aircraft was 5.25 NM from the DME LTE, the Enhanced Ground Proximity Warning System (EGPWS) issued a "CAUTION TERRAIN" alert. Shortly after, at 4.75 NM from the DME LTE and at an altitude of 1,280 feet, the system issued a more severe "TERRAIN, TERRAIN, PULL UP" warning.
Because the flight was operating under daylight Visual Meteorological Conditions (VMC) and the crew could visually confirm that no terrain or obstacles were in their immediate path, they chose not to execute the full terrain avoidance maneuver. Instead, the crew disconnected the autopilot and autothrottle, leveled the aircraft, and resumed a corrected descent profile. The aircraft landed safely on runway 21 at 13:49:33 without further incident or damage.
The investigation
The investigation examined the flight path, the crew's use of the MCP altitude windows, and the aircraft's descent profile relative to the established approach minimums. The investigation also reviewed the operator's Quick Reference Handbook (QRH) and operating manuals regarding the crew's response to EGPWS alerts.