The glitch on Singapore Airlines flight SQ37 saw the aircraft sending a 7500 transponder code shortly after departure.

However, the flight carried on its normal course while the transponder code was no longer being received indicating a glitch, according to the Daily Mail newspaper in London.

A spokesman for the airline confirmed there was no emergency on board the plane and that it had contacted the pilots of the aircraft. However, he did not explain why the code was sent out.

“The pilots have confirmed that there is no emergency on board. The flight is en route to Singapore and is scheduled to arrive on June 12 at around 7.50am local time,” he said.

The 7500 transponder code is one of three international emergency codes. It is sent by pilots in the event of hijackings, to alert air traffic controllers and for the appropriate action to follow.

The only time Singapore Airlines suffered a hijacking was in 1991 when four Pakistani men took over the aircraft soon after take-off from Kuala Lumpur, demanding the release of the husband of Benzar Bhutto, then Pakistan’s prime minister.

Negotiations were held after the plane landed in Singapore, but armed forces stormed the plane eight hours later and killed all four men. None of the hostages were killed.