A British Airways flight bound for Chicago from London Heathrow reportedly declared an emergency while flying over Ireland on Monday after rapidly losing altitude, according to flight-tracking data cited by British media.

Flight BA295, operated by a Boeing 777-200ER, was travelling from Heathrow to Chicago O’Hare when it transmitted the international emergency transponder code 7700.

The aircraft, registered as G-VIIA, had taken off from Heathrow Terminal 5 at around 11:50 am local time. It had climbed to approximately 37,000 feet during the flight before descending sharply to about 9,000 feet while over Ireland, the tracking data indicated.

The sudden altitude change occurred roughly an hour after departure, as the aircraft was beginning its transatlantic journey towards the United States.

Aircraft reportedly heads back to Heathrow

Flight-tracking information subsequently showed the aircraft turning towards the United Kingdom, indicating that the scheduled Chicago flight had been abandoned and the plane was returning to Heathrow.

The exact reason for the emergency was not immediately known.

There was no immediate information on whether the descent was prompted by a technical issue, a medical emergency or another operational concern. British Airways had not initially released details about what happened or confirmed the reason for the aircraft’s reported return.

What does squawk 7700 mean?

The 7700 code is used internationally by aircraft crews to alert air traffic controllers that they are dealing with a general emergency.

Once activated through the aircraft’s transponder, the code is displayed on air traffic control systems and can prompt controllers to give the aircraft priority or arrange other assistance.

However, the code itself does not reveal what has gone wrong. It can be used for a range of situations, including technical problems, medical emergencies, severe weather or other circumstances requiring immediate attention.

Air traffic controllers typically establish contact with the flight crew after receiving the 7700 signal to determine the nature of the emergency and coordinate the appropriate response.

Further details about BA295, including the reason for the emergency descent and the aircraft’s final destination, were awaited.