In an abrupt twist, Britain plans to phase in an opening of its air space tonight at 10 p.m. London time, which would be shortly from when I am posting this around 1.30 p.m. Pacific time.
Let me note, there is some remarkable stuff in this statement from the UK Civil Aviation Authority (CAA), which has come front and center amid growing criticism of two for-profit companies that have been largely setting the agenda in British response to the crisis, the National Air Traffic Services (NATS) and the Met Office. Both NATS and the Met Office have been criticized for allegedly overreacting to the situation starting last week.
An example of some remarkable stuff in the announcement: The news that aircraft manufacturers (whose specifications are sunk into the bedrock of aviation safety standards) have "increased tolerance levels" for flying near low-ash areas.
Anyway, here is the statement from the CAA, the UK’s aviation safety regulator, issued in conjunction with the Irish Aviation Authority.
"New guidance allows a phased reintroduction from 2200 tonight of much of the airspace which is currently closed due to the volcanic ash plume over the UK. There will continue to be some 'no fly zones' where concentrations of ash are at levels unsafe for flights to take place, but very much smaller than the present restrictions. Furthermore, the Met Office advise that the 'no fly zones' do not currently cover the UK.
... The CAA has drawn together many of the world’s top aviation engineers and experts to find a way to tackle this immense challenge ... Current international procedures recommend avoiding volcano ash at all times. In this case, owing to the magnitude of the ash cloud, its position over Europe and the static weather conditions, most of the EU airspace had to close and aircraft could not be physically routed around the problem area as there was no space to do so.
We had to ensure, in a situation without precedent, that decisions made were based on a thorough gathering of data and analysis by experts. This evidence-based approach helped to validate a new standard that is now being adopted across Europe.
The major barrier to resuming flight has been understanding tolerance levels of aircraft to ash. Manufacturers have now agreed increased tolerance levels in low ash density areas. [Italics mine]
Our way forward is based on international data and evidence from previous volcanic ash incidents, new data collected from test flights and additional analysis from manufacturers over the past few days. It is a conservative model allowing a significant buffer on top of the level the experts feel may pose a risk.
In addition, the CAA’s Revised Airspace Guidance requires airlines to:
--Conduct their own risk assessment and develop operational procedures to address any remaining risks;
--Put in place an intensive maintenance ash damage inspection before and after each flight; and
--Report any ash related incidents to a reporting scheme run by the CAA."