First, the aircraft appeared as an indiscernible speck of white and blue lights in the western horizon and as it closed in, it looked much like a vampire bat swooping in for the kill. Completing the second leg of its record-breaking attempt to fly around the world using only sun's rays, Solar Impulse 2 (SI-2), landed in Ahmedabad late Tuesday night.

"This is an attempt in aviation to inspire people to fulfil their dreams, take some risks in their lives and reach their goals. Aviation is really the symbol of pioneering," Bertrand Piccard, Chairman of SI-2, told BusinessLine , immediately after he stepped out of the cockpit.

Nobler cause

However, there is a much nobler cause behind SI-2. "The flight is an experiment into using solar energy for flying and other day-to-day needs," said Piccard, who piloted the plane on the second leg from Muscat to Ahmedabad's Sardar Vallabhbhai Patel International Airport.

This leg is also a milestone in the plane's 35,000-km journey, as it completed the first sea crossing by flying over the Arabian Sea. The plane does not use fossil fuels, and flies solely on solar energy.

SI-2 features

SI-2 is a single-seater aircraft made of carbon fibre. It has a 72-metre wingspan, much larger than that of Boeing 747 and weighs 2,300 kg. Of the total weight, 30 per cent is that of batteries, which enable the propeller-driven aircraft to fly even at night.

"The one-word behind SI-2 is innovation. This has already inspired many people to think out of the box and the flight has already become a movement over the Internet," said Tony Henshaw, Chief Sustainability Officer at Aditya Birla Group.

Aditya Birla Group is the India host for the SI-2.

The journey

An idea born in Switzerland, SI-2 started its round-the-world trip from Abu Dhabi, with the first pit stop at Muscat, Oman. From its second stop in Ahmedabad, it would fly to Varanasi on March 15, and then to Myanmar, and to China.

The aircraft will fly across 10 countries, making 12 stopovers and will fly over Pacific and Atlantic oceans before finally ending the journey at Abu Dhabi.

"The moment of truth is while flying over both the oceans, when it has to fly non-stop for five days and five nights. This is also a human challenge, and a challenge for the machines," said SI-2 Chief Executive Officer Andre Borschberg, who flew the first leg of the journey.

The aircraft had invitations from Mumbai and New Delhi airports, but has decided to make its stopover in Ahmedabad as there are many products and technologies in the plane manufactured by companies with presence in Gujarat. Bayer, ABB and Solvay are among those companies.

Unmanned solar flight

The duo has plans to develop an unmanned solar plane that would fly 20,000 metres high and stay in the air for much longer. "This is feasible in the next five years," said Piccard.

On the commercial viability of the aircraft, Borschberg said citing the example of Wright Brothers who also did not have the technology at the time of their first flight.

"But it will be definitely possible," he added.