Czechs Investigate TAP A320 Low Altitude Incident Near Prague

Czech aviation authorities have launched a formal investigation into a serious incident involving a TAP Air Portugal Airbus A320neo that descended significantly below its cleared altitude during approach to Prague. The event, which occurred on January 17, 2026, triggered multiple automated warnings and intervention from air traffic control, averting a potential Controlled Flight Into Terrain (CFIT) accident.

The Czech Ústav pro odborné zjišťování příčin leteckých nehod (ÚZPLN), the nation's Air Accidents Investigation Institute, has classified the event as a "serious incident" and is leading the inquiry. The incident highlights the effectiveness of modern, layered safety systems while underscoring the persistent risks associated with approach and landing phases of flight, particularly in adverse weather.

Incident Details

The aircraft involved was an Airbus A320neo, registration CS-TVG, operating as flight TP1240 from Lisbon (LIS) to Prague (PRG). According to a preliminary notification published by the French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA), the crew had been cleared to descend to an altitude of 4,000 feet. However, the aircraft continued its descent well below this minimum safe altitude.

Data indicates the aircraft reached a low point of approximately 300 meters (968 feet) above the terrain while still about 30 kilometers west of the Prague airport, near the area of Křivoklát Castle. At the time of the deviation, the aircraft's descent rate was approximately 3,000 feet per minute. The crew initiated a climb and go-around maneuver only after receiving two distinct warnings from Air Traffic Control (ATC) and a terrain warning from the aircraft's onboard systems. The flight subsequently executed a new approach and landed safely. Weather conditions at the time were reported to be poor, with mist, patches of fog, and low clouds.

Investigation and Official Response

The ÚZPLN officially opened its investigation on February 12, 2026, under the provisions of European Parliament and Council (EU) Regulation No 996/2010, which governs civil aviation incident investigations. Josef Bejdák, deputy director of the ÚZPLN, confirmed the core details, stating, “Radar systems detected a deviation from the assigned flight altitude of 4,000 feet above ground level. The crew responded to instructions from air traffic control. We are investigating the situation as a serious incident.”

The investigation will likely focus on several areas, including human factors, crew situational awareness, and the technical performance of the aircraft's flight management and autopilot systems. Aviation analyst and pilot Jiří Hořínka commented on the potential causes: “Descending below the minimum sector altitude of 3,600 feet is a serious violation of regulations – and of common sense. The cause may have been an incorrectly selected autopilot mode or interference from a false signal from the Instrument Landing System (ILS).”

The Role of Layered Safety Systems

This TP1240 incident serves as a key case study in the successful function of modern aviation safety nets. The initial alert was generated by a ground-based Minimum Safe Altitude Warning (MSAW) system, which notified the air traffic controller of the aircraft's dangerous proximity to terrain. This prompted the controller to issue urgent instructions to the flight crew.

Simultaneously, the Airbus A320neo's onboard Terrain Awareness and Warning System (TAWS) would have provided audible and visual alerts inside the cockpit, commanding the pilots to take immediate corrective action. The combination of the ground-based MSAW and the onboard TAWS provided critical, redundant warnings that ultimately led to the crew executing a go-around, a standard procedure for discontinuing an unstable or unsafe approach. The prevention of a CFIT event in this case demonstrates how these systems are designed to work in concert to mitigate risk.

What Comes Next

The ÚZPLN will conduct a thorough analysis of flight data recorders, cockpit voice recorders, ATC communications, and crew statements to determine the root cause of the altitude deviation. A final report with safety recommendations is expected to be published upon the conclusion of the inquiry, though this process can often take a year or more. The BEA has published a preliminary notification of the serious incident, and the final findings will be made public by the Czech Air Accidents Investigation Institute.

Why This Matters

This incident is a significant event in European aviation safety. While alarming, it powerfully demonstrates the resilience of the current safety ecosystem, where automated ground and cockpit systems successfully backed up human operators to prevent a potential catastrophe. The findings from the investigation will be crucial for reinforcing pilot training on automation management and situational awareness, especially during approaches in challenging weather conditions, providing valuable lessons for airlines and regulators worldwide.

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