Solar-powered plane grounded 9 months in Hawaii by battery damage

A solar-powered plane halfway through an attempt to circle the globe will be grounded in Hawaii for at least nine months because of battery damage sustained during its record 118-hour flight to Oahu from Japan, the project team said on Wednesday.

The spindly, single-seat experimental aircraft dubbed Solar Impulse is not expected to take off on the next leg of its journey - a planned four-day, four-night flight to Phoenix, Arizona - until late April or early May 2016, the team said.

Additional time is needed to repair the plane's four batteries, which store energy from the sun during daylight hours to keep the aircraft powered overnight, allowing it to remain aloft around the clock on extreme long-distance flights.

The repairs and testing will then push the next available window for completing the plane's trans-Pacific crossing to next spring, in terms of both weather conditions and sufficient hours of daylight.

The batteries became overheated during the aircraft's initial climb after takeoff on June 29 from Nagoya, Japan, en route to Hawaii on the eighth and most challenging leg of the circumnavigation quest, officials for the mission team said.

Still, the pilot, Swiss aviator Andre Borschberg, and his team successfully completed the Japan-to-Hawaii leg, safely landing near Honolulu on July 3 after five days and five nights, or 117 hours and 52 minutes, airborne.

The trip shattered the 76-hour world duration record for a nonstop, solo flight set in 2006 by the late American adventurer Steve Fossett in his Virgin Atlantic Global Flyer. It also set new duration and distance records for solar-powered flight.

Borschberg and co-founder of the project, fellow Swiss pilot Bertrand Piccard, are aiming to achieve the first round-the-world solar-powered flight, alternating turns at the controls for each leg of the voyage.

A nine-month hiatus, while a setback for the crew, does not disqualify the team from claiming a place in the official world aviation record books if successful.

It merely adds to the total elapsed time for accomplishing the feat, said Art Greenfield, director of contests and records for the National Aeronautic Association, the U.S. chapter of the Swiss-based Federation Aeronautique Internationale, or FAI.

Citing the world body's "sporting code" for solar-powered airplanes, Greenfield said the operative rule states: "Any time spent on the ground between the start and finish shall be counted as flying time."

Subsequent teams may end up doing it faster, but "everybody remembers the first," Greenfield said.

The Swiss team hopes eventually to cross the finish line in Abu Dhabi, where they started on March 9.