The UK Civil Aviation Authority said that new arrangements put in place since last year’s volcanic ash cloud would ensure high levels of public safety while helping to limit any disruption in the event that volcanic ash affects UK airspace. But the CAA warned that disruption to aviation couldn’t be ruled out.
Since last year’s volcanic ash crisis, measures have been put in place to ensure preparedness for a similar event. In the event that UK airspace is affected, the following arrangements will apply:
- Areas of high, medium and low density ash will be identified using information provided by the Met Office’s Volcanic Ash Advisory Centre. This is based on data provided from the source of the volcano, satellite, and weather balloons, as well as ground based instrumentation such as radar,
- Information on the high and medium density zones will be communicated to the aviation industry by means of a Notice to Airmen (NOTAM),
- Any UK airline wishing to operate in areas of medium or high density ash, will need to have a safety case accepted by the CAA. Many airlines already have such safety cases in place and agreed for medium density.
- A safety case sets out the measures airlines will put in place to mitigate the risk of flying through ash. They also include input from aircraft and engine manufacturers. Safety cases have been used by airlines for many years to set out how they will safely deal with other unusual or challenging issues.
The three levels of ash density are defined as:
- Area of Low Contamination: An airspace of defined dimensions where volcanic ash may be encountered at concentrations equal to or less than 2x10-3 g/m3, but greater than 2x10-4 g/m3.
- Area of Medium Contamination: An airspace of defined dimensions where volcanic ash may be encountered at concentrations greater than 2x10-3 g/m3, but less than 4x10-3 g/m3.
- Area of High Contamination: An airspace of defined dimensions where volcanic ash may be encountered at concentrations equal to or greater than 4x10-3 g/m3, or areas of contaminated airspace where no ash concentration guidance is available.
The CAA has led work within Europe to update requirements for operating in and around Volcanic Ash. These operational requirements have now been published by the International Civil Aviation Organisation and are available to view here: http://www.paris.icao.int/documents_open/files.php?subcategory_id=63