A London-bound Cathay Pacific Airbus A350-1000 (CX257) triggered a NATO Quick Reaction Alert after failing to establish contact with Romanian air traffic control over Romanian airspace on 4 July 2026, prompting Hungarian Gripen fighters to visually intercept the aircraft. The alert, ordered at 13:42 CET, resulted in two fighter jets taking off at 13:51 and issuing a visual warning near the Hungarian border before the flight re-established communication. Hong Kong’s Civil Aviation Department expressed serious concern and mandated a comprehensive investigation report within one week. The airline confirmed safety was never compromised, communications were restored, and the flight continued to Heathrow as planned. The technical cause of the temporary communication loss remains undisclosed and under investigation.