The Air Accident Investigation Unit is looking into the circumstances surrounding the emergency landing of a US cargo plane at Shannon Airport last Friday night.

The incident came to light yesterday when listeners to RTÉ Radio One’s Liveline programme called and said they had seen a plane that seemed to be on fire landing at Shannon.

The airline, Murray Air, carries cargo for the US military and has a licence to carry explosives through Shannon Airport.

The Department of Transport says that the carriage of weapons and munitions is prohibited under the Air Navigation Order of 1977, unless an exemption order is made by the Minister for Transport.

The Department confirmed that 1,495 such exemptions were granted by the Minister in 2007.

In a statement, the Department also points out that under the Chicago Convention on International Civil Aviation non-scheduled flights are allowed to make landings, without the necessity of obtaining permission, if these are for non traffic purposes.

This includes fuel or technical stopovers where the aircraft are not putting-down or taking-up passengers or cargo.

The Department was informed last week by Murray Air that one of their flights would be making a stopover at Shannon last Friday night.

But the airline said it was not carrying dangerous cargo or explosives so an exemption was not necessary.

If it had been carrying such cargo, then an exemption would be needed.