A Ryanair captain issued a distress call just moments before landing after losing contact with air traffic control.
Flight FR642 left Valencia Manises Airport to undertake the two-and-a-half-hour flight to London Stansted Airport on Monday, September 22.
But the Boeing 737-800 reportedly lost communication with controllers on the ground due to a radio system failure.
Crews on board the 189-seat plane were forced to issue an emergency squawk code 7600 as it approached the Essex transport hub, according to FlightAware data.
The Civil Aviation Authority's Rules of the Air manual states that pilots must use the signal "to indicate a state of radio-communication failure”.
“In the event that the radio on the aircraft fails to function properly, communication can get cut off. This can lead to grave safety risks,” California Aeronautical University said.
“Because the aircraft cannot let the ATC (air traffic control) know verbally, they can immediately change the code in their transponder to Squawk 7600.”
They added: “This alerts ATC and, as the aircraft continues to travel as they should to their airport, ATC can make the necessary adjustments with those they can communicate with to ensure everyone in the sky is safe as the mute aircraft lands.”
The Ryanair flight kept steady at 9,000 feet for around 15 minutes while circling three times before arriving at Stansted at 12.40pm.
Pilots occasionally lose contact with air traffic control due to equipment failures or adverse weather conditions such as thunderstorms.
To mitigate these issues, pilots have established protocols, including switching to an emergency frequency or using a text messaging system.
The Standard has approached Ryanair for comment.
