On Jan 17th 2026, a TAP Air Portugal Airbus A320-200N, registration CS-TVG, came alarmingly close to terrain during approach to Prague after descending far below its cleared altitude, triggering air traffic control warnings and a terrain escape manoeuvre.
Operating flight TP-1240 from Lisbon to Prague, the aircraft was cleared for an ILS approach to runway 06. Approximately 17 nautical miles from the threshold, the jet was maintaining its assigned altitude of 4,000 feet when it suddenly entered a steep descent. The aircraft dropped to about 2,600 feet mean sea level—2,425 feet according to ADS-B pressure-compensated data—placing it roughly 1,000 feet above ground level in an area where the minimum safe altitude was 3,600 feet MSL.
According to information received by The Aviation Herald, the descent occurred at high speed and with a high sink rate. Czech investigators later reported the rate of descent was approximately 3,000 feet per minute, accompanied by increasing airspeed.
On Feb 12th 2026, the Czech Republic’s Ústav pro odborné zjišťování příčin leteckých nehod (UZPLN) confirmed that air traffic control detected the violation of the cleared 4,000-foot altitude and issued warnings to the crew. The controller alerted the flight twice. During the second warning, the crew reported a terrain warning and initiated an immediate climb.
Investigators stated that the aircraft’s lowest recorded radio altitude was 968 feet above terrain. The crew then performed a terrain escape manoeuvre, climbing sharply to approximately 5,850 feet before stabilizing. The aircraft entered a left 360-degree turn, subsequently levelled at 4,000 feet, and repositioned for another approach.
The second approach was uneventful, and the aircraft landed safely about 11 minutes after the premature descent. Despite the serious nature of the event, the jet later departed Prague for its return flight on schedule.
The UZPLN has classified the occurrence as a serious incident and continues its investigation. The event highlights how quickly altitude deviations during approach can erode critical safety margins—and how layered defenses, from ATC monitoring to onboard terrain warning systems, play a vital role in preventing controlled flight into terrain.
