Solar Impulse’s seven-week wait to cross the Pacific just got longer

Solar Impulse 2 was again grounded on Tuesday after a three-week wait in Japan for an elusive clear-weather window.

That window deteriorated just as pilot Andrew Borschberg was preparing in the cockpit for a five-day, five-night journey to Hawaii.

“We are at the limits of what we can do in terms of weather forecast, but I would not leave if I wasn’t confident,” said Mr Borschberg, who is also chief executive and co-founder of the project, earlier in the day.

The team behind the solar-powered aircraft had already been forced to divert the plane to Nagoya after takeoff in Nanjing, China, for the trans-Pacific leg. Bertrand Piccard, pilot and chairman of Solar Impulse, on Tuesday described the wait for safe weather conditions. “It’s the most difficult decision we have ever taken at Solar Impulse until now,” he said on Twitter.

The team has now been waiting seven weeks to move on to Hawaii because of previous delays in Nanjing. “We’re looking at third time lucky now,” Mr Borchberg said.

“It’s really a bad moment,” said Mr Piccard. “Andre was in the cockpit … we saw the conditions worsen. It was on the edge. It was yellow, green. We took the decision to go but not everybody was enthusiastic, but we had the consensus it was worth trying it. Now it is not worth trying.”

The crew was waiting for takeoff when a team member showed Mr Piccard the latest weather pattern. “I just saw on the screen that the corridor that the plane was supposed to go was full of clouds. Again, it changed,” he said.

The team had announced earlier on Tuesday that it planned to take off at 2.30am local time, but later said it had postponed take-off to perform checks. The team posted pictures of Mr Borschberg hugging his wife, Yasemin, before preparing for the journey.

Solar Impulse 2 took off from Abu Dhabi on March 9 on a historic round-the-world flight attempt without using fuel. The aircraft is powered by more than 17,000 solar cells placed on 72-metre wings.

This will be the eighth and longest of 13 expected legs of the journey. The planning for what could be a record-breaking flight took 12 years of development. Masdar and Abu Dhabi are mission partners.

Flight updates are available at www.solarimpulse.com.