The fact that a solar airplane prefers sunshine and clear skies might seem logical but not always sufficient. There are other conditions that need to be met for Solar Impulse to fly, turbulence and strong winds being the ultra-light, large wingspan aircraft’s least favorite. This means that in both takeoff and landing cities as well as at different altitudes along the way, the weather needs to be mild.  

That’s why Solar Impulse has its own team of meteorologists and analysts who constantly monitor the weather, inputting the data to develop multi-variable forecasts. Unfortunately, the unfavorable weather windows are still more frequent than the favorable ones for the Dallas (TX) to St. Louis (MO) leg. Clear skies and low turbulence rarely make a team in this unstable, tornado-struck period.

These conditions might cause flights to be delayed but the consequences have been nothing but positive. It has allowed the Solar Impulse team to open the hangar doors to the public more frequently than initially planned and it’s also turning out to be the perfect training exercise for the meteorologists and pilots alike. For example, during the flight from Phoenix to Dallas, André made good use of his long career as a pilot: the landing at Dallas Fort Worth was challenging with winds peaking at 30 knots, (meaning the plane was flying at zero groundspeed) and had to approach the runway sideways, a situation never experienced before in this airplane.

“When we set out for this endeavor we always knew the path wasn’t going to be smooth, but in true Solar Impulse spirit we prefer to keep a positive outlook on things and turn problems into opportunities.” This is Bertrand and André’s most famous sentence and, I must admit, it’s quite contagious!