Sunday, 9 April, 2000, 07:51 GMT 08:51 UK
US military trial plane crashes
The Osprey MV-22 has only just come into service (courtesy US Navy)
A plane under development with the United States Marine Corps has crashed in a fireball while landing at an Arizona airport, killing all 19 people on board.
Analysts described the accident as a serious setback for a key Pentagon development programme.
Police said the MV-22 Osprey came down at about 2000 (0300 GMT) at Avra Valley Airport in Marana, west of Tucson, in fair weather.
Firefighters at the crash scene
Witnesses reported seeing the revolutionary plane plunge after an explosion in the sky.
"It was fully engulfed and there were small explosions," said Katy Heiden, a fire service spokeswoman.
Television pictures showed smoke rising from a smouldering wreckage that was lit up by lights from emergency vehicles.
In a statement, President Clinton mourned a "terrible loss of life" which he said was a reminder of how many men and women in the US military put their lives at risk every day.
The plane had flown from a Marine air station at Yuma, about 400 km (240 miles) away. All those on board were Marines. Four were crew, the rest passengers.
The Marine Corps' Osprey is a new, tilt-rotor aircraft undergoing final evaluation. It was introduced only last September, and flies like a plane but can land and take off like a helicopter.
Its two propjet turbines power two huge propellers.
The Osprey MV-22
Capable of 640 kph (400 mph)
Altitude up to 25,000ft
Can carry 24 troops
Seven-month evaluation began in October
Full deployment by 2015
The Osprey flies at twice the speed, has twice the range and can carry heavier loads than the Vietnam-era CH-46 helicopters it will replace in the Marine Corps' inventory.
Military planners see the aircraft as a means of getting more troops and pilots safely out of danger zones.
On search and rescue missions, the aircraft can fly long distances at low altitudes, and hover to pick up survivors.
But there have been criticisms of the plane's cost and safety.
Early safety concerns plagued the aircraft, but the manufacturers - Bell Helicopter Textron and Boeing - say modifications from the original design have made it lighter and safer.