United 737 Gets TCAS Alert as Black Hawk Crosses Final at Santa Ana

SANTA ANA, Calif. — A California National Guard UH-60M Black Hawk helicopter crossed the final approach path of a United Airlines Boeing 737-800 on March 24, triggering an automated collision avoidance alert near John Wayne Airport.

The incident occurred around 8:40 p.m. as United Flight 589 descended through 2,000 feet. The Traffic Collision Avoidance System alert prompted the jet crew to level off at 1,425 feet to maintain vertical separation from the helicopter, identified as Callsign Knife 25, which was conducting a routine training mission returning to Joint Forces Training Base Los Alamitos.

The Federal Aviation Administration opened a formal investigation following the Resolution Advisory. According to data analysis from flight recorders and air traffic control audio, the aircraft were approximately 525 feet vertically and 1,422 feet laterally apart at their closest point. The close call raises questions about air traffic control procedures in high-traffic coastal corridors, occurring less than a year after the January 2025 Potomac crash near Reagan National Airport that led to new mandates for radar-based separation of helicopters and airliners.