NLR Research Aircraft Examines Volcanic Ash in Air Space

AMSTERDAM, April 20, 2010 - The National Aerospace Laboratory's (NLR) research aircraft has
investigated the volcanic ash cloud hovering over the Netherlands. The
purpose of this flight was to verify the accuracy of atmospheric models
currently being used to predict the movements of the ash cloud.

From the flight undertaken by the Cessna Citation on Sunday night above
the Netherlands' southern provinces, it emerged that the ash cloud is highly
visible. The edges of the ash cloud hovering above the country's southern
provinces were also highly visible, which is crucial information for pilots
when the air space is (temporarily) opened.

The objective of this flight was to verify the accuracy of the models the
Royal Netherlands Meteorological Institute (www.knmi.nl) uses to
calculate the movements of the volcanic ash cloud. These measurements are
then used by the Dutch aviation authorities to take decisions regarding the
closing and (re)opening of air space.

Sunday night's flight revealed that the models had accurately estimated
the location of the volcanic ash layer. The NLR's research aircraft flew over
the ash cloud, which at the time was hovering at a height of 3 kilometres and
was comprised of varying thicknesses.

There are very few methods currently available in Europe for precisely
measuring and tracking volcanic ash. Moreover, there are no set regulations
in place for determining which ash particle concentration levels necessitate
the opening (or closing) of air space. NLR researchers are therefore
currently working closely with other institutes, including the Royal
Netherlands Meteorological Institute, the National Institute for Public
Health and the Environment, the Dutch Ministry of Defence, the Ministry of
Transport, Public Works and Water Management, and Eurocontrol. This joint
research will determine the best methods for quickly and safely launching
sensors and measuring instruments capable of accurately monitoring volcanic
ash.

NLR, Sam Lampers, lampers at nlr.nl, Office: +31(0)20-5113032