Solar Impulse 2 has taken off for the final time, but its crossing of the Saudi desert – managing no-fly zones, wind and heat – could make its last flight the most difficult.
Swiss pilot Bertrand Piccard, who took off from Cairo on Sunday and is expected to land in Abu Dhabi on Tuesday, will be navigating a region riven by tensions and conflicts that prevented him from taking the most direct path to Abu Dhabi.
High temperatures will also test the limits of the plane, forcing Mr Piccard to wear an oxygen mask for extended periods.
“We have never had to deal with temperatures so high before on our round-the-world tour, but a little challenge at the end of our mission is always good,” the team said on its blog.
Thermals, caused by heat rising from the desert, were likely to create turbulence for the plane. In those conditions, autopilot cannot be activated and Mr Piccard will have to be alert to stabilise any tilting.
To avoid the worst of the turbulence, Mr Piccard is likely to ascend to a higher altitude in the unpressurised and unheated cockpit for longer than is typically required. Holding in areas for hours on end to reach certain altitudes could drain the plane’s batteries.
And the on-board electronics – which rely on ambient air to cool – could cause overheating at higher altitudes, leading to a drop in air density.
Without a fan to cool them, Mr Piccard will need to take care to not overheat the devices that could help to save his life in a clinch.
The most challenging part, and coincidentally the hottest, will be upon arrival at Abu Dhabi’s Al Bateen Executive Airport, where the plane will encounter 35°C heat.
The estimated ambient air and runway temperature were the leading causes behind the team’s decision to land at night.
After leaving Cairo at 3am UAE time on Sunday, Mr Piccard described his view of the Saudi coastline while crossing the Red Sea.
“Thank you #SaudiArabia for this very friendly welcome over your country,” he said on Twitter.
The final flight of the historic round-the-world journey was delayed in Cairo last week because of a last-minute turn in weather conditions.
Mr Piccard also had an upset stomach that would have meant problems over the duration of the flight. Solar Impulse took off in Abu Dhabi in March last year and the Masdar-sponsored project has since stopped in 16 cities to raise awareness about the viability of renewable energy.
Andre Borschberg, the project’s co-founder and co-pilot, described the effort to complete the first solar-powered, zero-fuel circumnavigation of the Earth.
“Today we are living the final moments of a once-in-a-lifetime adventure contributing to setting a new milestone in aviation,” Mr Borschberg said.
“It is one centred not on speed or height, but instead on exploring new clean and efficient technology that can almost make it possible for the plane to fly with unlimited endurance, a week, a month; something that was never done.”
(via The National)