IAA defends ash calculations

The chief executive of the Irish Aviation Authority Eamonn Brennan has defended the methodology used to ascertain levels of ash density in the atmosphere.

Speaking this morning, Mr Brennan denied the authority uses a single source of data to determine the safety of the skies over Ireland.

Mr Brennan was reacting to a call from Aer Lingus chief executive Christoph Mueller who told RTÉ radio that the current method of mapping the presence of volcanic ash is not reliable.

Mr Mueller advocated the use of different measurement techniques as used in the Americas where he said computer models and measurements are in place which allow aircraft to fly around ash clouds with "high precision".

Aer Lingus called for specialist aircraft “equipped with appropriate measurement devices” to be deployed around the Atlantic rim as a part of a European initiative to respond “swiftly and decisively to any approaching ash cloud”.

While the IAA’s Eamonn Brennan agreed that more test flights would be of value, he insisted comparisons with countries such as Alaska were not valid as conditions there are ‘completely different’.

Mr Brennan told RTÉ's Morning Ireland the current ash cloud occurred in an area very close to intense air traffic where Europe has some 1,900 flights a day across the north Atlantic and as many as 30,000 flights a day over Europe.

The IAA chief executive said the methodology used has to be “evidence based”.

He said the IAA uses the VAAC [the UK Met Office’s Volcanic Ash Advisory Centre] model, which is the accepted norm as it is approved by the engine manufacturers. He said results from test flights conducted by other countries were also taken into consideration.

He also added that the IAA is in contact with the Icelandic met office, the Icelandic CAA and also uses weather radar and satellite technology to determine levels of ash in the atmosphere.

“We wouldn’t rely on a single source to make a decision and nobody in aviation would do that”, Mr Brennan said.

Ryanair issued a statement supporting the Aer Lingus call on the use of US-style measurement methodologies.

It accused EU governments (and their regulatory authorities) of engaging in "excessive and inappropriate" closures of EU airspace where the airline claimed no evidence of volcanic ash concentrations or diminution of air safety is present.

Ryanair called on EU governments to adopt similar volcano response measures as in the US (which establishes small no fly zones around volcanoes), and to stop "these inappropriate and unnecessary closures of vast swathes of European airspace", some of which it said are "thousands of kilometres from Iceland".

The call followed confirmation by the airline yesterday that two of its aircraft that landed at Belfast City Airport at the weekend had traces of ash in their engines.

The two planes, which were due to fly to London, were grounded on Sunday. They were returned to service yesterday following a six-hour "deep clean".

Stephen McNamara of Ryanair said the traces were "safe levels" of volcanic ash. The ash was found on aircraft which flew between Ireland and the UK in open unrestricted airspace on Sunday.

"Even when airspace is open there still may be remains of volcanic ash. It doesn't disperse straight away but these levels are safe", Mr McNamara said.

"There’s absolutely nothing to worry about. First of all, these levels were low and second of all they were [with]in the manufacturer’s guidelines and third of all, they were identified", he said, adding that "nobody was exposed to any risk whatsoever”.