United Airlines halted all mainline flights across US on Thursday after a fire alarm triggered an emergency evacuation at its Chicago-area operations centre.The alarm sounded at the airline’s Network Operations Center in Arlington Heights. It led to a temporary nationwide ground stop, affecting hundreds of flights. United Airlines confirmed that employees were moved to a nearby backup facility as a precaution.“A fire alarm sounded at our operations center, which caused employees to move to our nearby backup facility and resulted in a brief nationwide ground stop of United aircraft,” the airline said in a statement to Fox News. “Employees have returned to our primary operations center, and the ground stop has been lifted.”The federal aviation administration (FAA) issued an advisory around 6:30 pm local time, confirming the temporary suspension of United’s operations. Although no fire was confirmed at the facility, the decision to halt all flights was taken out of caution.The disruption led to over 200 delays across the country by Thursday evening, according to flight tracking website FlightAware. Service was restored within about an hour.United Airlines operates the world’s largest fleet, with more than 1,000 aircraft, according to the Mirror. The latest incident adds to a string of operational problems faced by the carrier. In 2023, a software issue led to a similar ground stop, delaying hundreds of flights.Just over a week ago, on July 16, a United flight bound for Sarasota, Florida, was forced to return to Chicago’s O’Hare International Airport shortly after takeoff due to an engine warning. The Boeing 737 crew reported low pressure in engine number two, prompting an emergency landing.Social media was flooded with images of grounded planes and passengers waiting for updates during Thursday’s halt.
