A flight made an emergency landing because of 390 cows on board. The pilot decided to land the aircraft in Heathrow because the 390 cows were giving off too much heat and set off a fire alarm.

The Boeing 747, carrying 390 cows, was flying over the Irish Sea when a fire warning went off from the deck where the animals were being kept. Thinking there may have been a fire on board, the pilot decided to land. However, there was no fire. Upon inspection, technicians later found that there was no evidence of smoke or flames. The cows were giving off so much body heat that it set off the alarms, the technicians concluded, according to Sunday People.

A cow's average body temperature is 38.6C or 101.48F, which is slightly higher than a human's body temperature. In addition to a high temperature, cows also release 100-200 liters of methane a day through flatulence. Under the circumstances in which close to 400 animals were crowded together, releasing gas emissions and spreading body heat, the temperature on the plane may have increased and set off the alarm.

This emergency landing was one of 1,262 distress signals sent to a UK airport over the past two years according to Sunday People. On average there were two a day. Data from the Civil Aviation Authority showed that 186 of those signals were maydays and 1,076 were less urgent pan-pan situations. Some of the incidents include bird strikes and crew members falling ill.

According to aviation expert David Learmount from the website Flightglobal, "A ­mayday or pan-pan call doesn't mean you will have a ­disaster. Usually ­nobody is hurt."