(AP) -- A Swiss team planning to circle the globe in a solar-powered plane has postponed a 24-hour test flight because of an equipment problem.
Bertrand Piccard, co-founder of the Solar Impulse team, says he cannot say when the next attempt will be made.
But he says the test flight has to happen before the beginning of August because after that the days will be too short to charge the plane's batteries to last through the night.
Pilot Andre Borschberg says the problem is with a piece of measuring equipment.
Piccard told supporters and reporters at the Payerne airfield in Switzerland on Thursday that it was the team's first setback.
"If this project was easy, everybody else would have already done it," he said.
Explore further: Swiss team plans to fly solar plane all night