The pilot of a civilian Second World War stunt plane was killed today when he crashed while practising for an air show, US officials said.

A helicopter belonging to the Nato-led international security force in Afghanistan crashed in the west of the country today, killing 17 Spanish troops. The cause was not immediately clear.

NATO has launched its training mission for Iraqi forces by sending a small group of officers to the country to consult with authorities and to prepare logistics.

Just two days before Columbia’s mysterious break-up during its fiery descent, a safety engineer warned by e-mail about risks of “catastrophic” failures from extreme heat causing the shuttle’s tyres to burst inside the spacecraft, Nasa has disclosed.