A Korean Airways cargo flight made an emergency mayday landing at Heathrow airport when the fire alarm on board was triggered over the Irish sea.
Gas masks in place, the crew proceeded to investigate. Instead of a blaze, they found that the 390 sweaty cows in cargo had inadvertently set off the alarm.
Cows produce a high level of methane gas - the second most significant heat-trapping emission. This raised humidity levels inside the aircraft, triggering the alarm.
According to the Daily Mail, "the Korean Airways landing at Heathrow is one of 88 mayday calls reported to the Civil Aviation Authority (CAA) last year. A mayday landing is the highest level of emergency and is rarely used except in the most urgent cases."
Mayday landings have occurred in the past for many reasons including sick crew members, terrorism suspects and low fuel levels. Flatulent cows is probably a first though.