THE AIR Accident Investigation Unit is investigating the circumstances surrounding a US plane making an emergency landing at Shannon last weekend.
The operators of the cargo aircraft declined to say what was on board this particular flight but confirmed that it is licensed to carry ammunition, as well as depleted uranium and that the US military is one of its customers.
A spokeswoman for the Department of Transport has said it has "no record" of an application from any airline to transport depleted uranium through Irish airspace - or to land at an Irish airport.
However, she did not say what procedures, if any, are in place to establish the contents of such commercial cargo aircraft travelling through Irish airports.
The department spokeswoman last night confirmed that Friday night's incident is being investigated by the department's Air Accident Investigation Unit.
She said the carriage of weapons and munitions on board flights is prohibited unless an exemption has been obtained from the Minister for Transport, Noel Dempsey. While the Minister granted 1,495 such exemptions last year, his department has no record of any application from "any airline to transport depleted uranium through Irish airspace or to land at an Irish airport", she said.
"On 25th March, Murray Air notified the Department of Transport that one of its aircraft would be operating a technical/fuel stop at Shannon on the 28th March 2008," she said.
"Murray Air indicated that no dangerous air cargo or hazardous material would be on board the flight. Accordingly, there was no requirement for Murray Air to apply for an exemption under the above legislation.
"However, if hazardous goods or munitions had been carried, Murray Air would have been obliged to apply for an exemption under the above legislation."
But speaking on RTÉ radio's Liveline programme yesterday, Tracy Bell, a spokeswoman for Murray Air, said it is licensed to carry explosives, armaments and other munitions. Asked if the licence included the carriage of depleted uranium, she said it did.
"It's an insurance-based licence. we are insured to do so, we are therefore licensed to do so. That does not necessarily imply that we have used the licence to transport uranium," she said.
Ms Bell said Friday night's flight was en route to Doha in Qatar from Shannon when it encountered a compressor failure in one of its engines, forcing the pilot to return to Shannon airport.
Despite some eyewitness claims to the contrary, she said the airplane did not "dump" fuel as a result of the emergency procedure.
She also insisted that the aircraft in question was not carrying any explosives or other armaments. But she declined to say what its contents were, or who her client was. The DC 8 aircraft took off from Shannon airport at approximately 10.20pm on Friday night, en route to Qatar.
Shortly after take-off the aircraft experienced an engine problem. Loud bangs were heard in the local area and some flames were seen coming from an engine.
As a result, the pilot made a precautionary shutdown of the number one engine, re-started it and carried out a precautionary landing with four engines back at Shannon, according to the Department of Transport.
Preliminary indications are that the aircraft suffered a compressor stall, which is a restriction of airflow through the engine, possibly due to a build up of ice in the engine intake, the department spokeswoman added.