April 18 – Reuters: “KLM says test flight reveals no damage from ash“
NATS (Sunday morning): “the restrictions currently in place across UK controlled airspace will remain in place until at least 0100 (local time) tomorrow, Monday 19 April.”
NATS (Sunday April 18, 1500-UK): “the restrictions currently in place across UK controlled airspace will remain in place until at least 0700 (local time) tomorrow, Monday 19 April.” Next decision at around 2100 (local time), today. Though they do now concede that they “are working closely with Government, airports and airlines, and airframe and aero engine manufacturers to get a better understanding of the effects of the ash cloud and to seek solutions“.
Reuters: “German airlines complain over airspace closures“ (Lufthansa raises issue of claiming damages).
“The closure of the air space happened purely because of the data of a computer simulation at the Volcanic Ash Advisory Centre in London,” said Air Berlin Chief Executive Joachim Hunold, speaking to Bild am Sonntag. Perhaps UK forecasters got it wrong again and it was simply “the wrong kind” of ash
3:40pm – British transport minister Andrew Adonis: “European Union transport ministers will consider on Monday whether flights could resume even if volcanic ash from Iceland remains in the atmosphere“.
4:51pm – BBC: “Europe’s airlines and airports question flight bans“.
NATS (Sunday April 18, 2100-UK): “the current restrictions across UK controlled airspace due to the volcanic ash cloud will remain in place until at least 1900 (local time) on Monday 19 April.” . . . . The next update will be issued at approximately 0300 (local time).

NATS say they are “currently awaiting CAA guidance” and the CAA say they are “working with NATS and UK airlines to ensure safety compliance during the current restrictions on airspace.” This does not seem to imply – to me at least – that the CAA was involved the decision. It is simply making sure aircraft don’t fly where NATS tells them they can’t. I would expect some severe buck-passing over the next few days as well as a reverse-ferret from the media.

Monday April 19, 0830: NATS extended it to at least 0100 (local) on Tuesday 20th April.

The CAA has said : “The Civil Aviation Authority (CAA), the UK’s independent specialist regulator with oversight of aviation safety, today issues new guidance on the use of airspace. This is issued in conjunction with the Irish Aviation Authority (IAA) and covers the Anglo Irish Functional Airspace Block (FAB).

The 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.

Making sure that air travellers can fly safely is the CAA’s overriding priority.

The CAA has drawn together many of the world’s top aviation engineers and experts to find a way to tackle this immense challenge, unknown in the UK and Europe in living memory. 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.

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.

The CAA will also continue to monitor the situation with tests both in the air and on the ground.”

NATS follwed up at 2040(UK) with “NATS has received new direction from the UK’s safety regulator, the CAA, on applying restrictions to UK airspace following the volcanic eruption in Iceland.

As soon as revised accurate information is available from the Met Office on the location of the dense ash cloud, NATS will review airspace availability and provide an update to airline operators on any airspace that has been restricted for safety reasons. We will issue a further statement by 2200.”

Reuters: “Britain reopens all its airspace“. Curiously, this report says “The first British Airways flight from Vancouver landed at London Heathrow, normally the world’s biggest international airport, shortly before 2100 GMT” (ie 2200 current UK time).

Tuesday April 20, 2300 (UK): NATS welcomes new CAA guidance and reopens airspace
“We are delighted to report that most restrictions on UK airspace began to be lifted at 2134 (local time) this evening, following new guidance from the UK’s safety regulator, the Civil Aviation Authority on restrictions to UK airspace as a result of the volcanic eruption.”