Paris, June 12 2011 РThe solar airplane of Bertrand Piccard and Andr̩ Borschberg, Solar Impulse, who was trying to fly from Brussels to Paris Le Bourget last night, had to turn back half-way and land back in Brussels where it had taken off.

The weather conditions are the primary reason for returning to Brussels. The wet and windy conditions this afternoon delayed the HB-SIA take off until 18:36 (UTC +2) which meant it did not have enough time in the sun to recharge its batteries. The cloud cover, which was greater than estimated, compounded the problem, as did the head winds and down drafts that André Borschberg encountered underneath the cumulus clouds. The HB-SIA was forced to fly at a lower altitude than planned and consequently used up its batteries too quickly putting it at risk before reaching Paris.

Solar Impulse’s Flight Director, Raymond Clerc, decided to favour safety. “It isn’t really a surprise, more of an illustration of how challenging this particular flight is. Under no circumstances will we take a risk. We therefore decided to return to Brussels where the technical team was awaiting the HB-SIA to land. We hope to have a weather window soon that is long enough for a safe flight to Paris.”

André Borschberg, CEO and co-founder of Solar Impulse, said that: “We knew that it would be very difficult due to our late take-off. Because of the weather, the level of charge of the batteries went down faster than expected, and we considered that it was safer to turn back. This setback is at the heart of what Solar Impulse is all about. It is an experimental project and we therefore make attempts that aren’t necessarily always successful.”

For Bertrand Piccard, the initiator and Chairman of Solar Impulse : “What is surprising is not so much that we had a problem last night, but that we never had one until now. The success of the first flights gave a wrong impression that things were easy.”

Flight Report (UTC +2)
Brussels – Idoko – Brussels
Pilot:	André Borschberg, CEO and co-founder
Take-off time:	11/06/2011 18h36
Time of decision to fly back:	11/06/2011 21h39
Time of landing:	11/06/2011 23h49
Flight duration:	5 hours 13 min
Average speed:	40km/h
Average altitude:	915 metres (3000 feet)
Distance :	205 km

Source and photo: Solar Impulse