Around-the-world solar flight nears completion

The final flight, with Bertrand Piccard as pilot, took off from Cairo on July 23 at about 7:30 p.m. Eastern Daylight Time as leg 17 of an effort that began in Abu Dhabi in March 2015.

The concluding hours of flying the aircraft outfitted with 17,000 solar cells were proving challenging because of weather as Piccard, the mission’s co-founder, made his way along the approximately 1,470-nautical-mile course.

“After confronting new flight conditions, including high temperatures, upward and downward drafts, and winds in the flight planning, the night was turbulent and it was difficult for Bertrand Piccard to sleep,” the team reported on its website. “This flight will prove the power of clean technology to change the world; the beginning of the clean technology revolution. (Co-founder) André Borschberg brought Si2 to Cairo, Egypt on July 13 after crossing the Mediterranean Sea and now Si2 is about to complete the full circle, arriving at the beginning of the adventure.”

With 90 percent of the final leg complete about 1 p.m. Eastern Daylight Time on July 25, Solar Impulse 2 was flying at 17,000 feet, its batteries at 95 percent, discharging, according to the mission’s online logbook.

Piccard and Borschberg had alternated flight legs on the mission, with Borschberg concluding his final leg—the Seville, Spain-to-Cairo route—“after two days of flight and a flyover of the pyramids,” the team said.

On the occasion of the July 13 landing in Cairo, AOPA reported that Piccard’s vision of flying an airplane around the world on solar power to promote clean energy had originated in the Egyptian city after he completed a nonstop, round-the-world balloon flight there in 1999.