Record-breaking solar plane nears Hawaii

A solar-powered plane on the riskiest leg of a round-the-globe bid is closing in on Hawaii after a record-breaking flight which has tested its exhausted pilot to the limit in "difficult" conditions.

Veteran Swiss aviator Andre Borschberg, who has spent more than four days flying from Japan in the Solar Impulse 2, was expected to land on the Pacific US island state yesterday if all goes well.

"After the longest and most tiring night of this flight, bringing the pilot and aircraft to the limits, Andre is now back under the oceanic sunlight," the mission organizers said in the latest update.

By 0200 GMT the plane had traveled 91 percent of the way to the tropical US state, having flown 7,471 kilometers (4,642 miles), with just 700 kilometers to go -- barely 12 hours of flying time, in theory.

More importantly, it had crossed a last cold weather front before Hawaii, which organizers described as "jumping over the wall" before the final stretch towards the Pacific archipelago.

The organizers' latest estimate for arrival is 1600 GMT, although that could change depending on conditions.

So far Borschberg has flown more than 104 hours -- easily beating the previous longest solo endurance flight by Steve Fossett, who flew for 76 hours and 45 minutes in 2006.

The whole trip from Japan to Hawaii was expected to take 120 hours.

The Swiss aviator is napping for only 20 minutes at a time to maintain control of the pioneering plane. He is equipped with a parachute and life raft, in case he needs to ditch in the Pacific.