The vehicle, with Bertrand Piccard at
the controls, left Mandalay in Myanmar (Burma) just after 21:00 GMT on Sunday,
and is heading for Chongqing in China.
The intention is to make a brief stop
there, and then try to reach Nanjing on the east coast of the country.
This would set up Solar Impulse for
the first of its big ocean crossings - a five-day, five-night flight to Hawaii.
Mission control will not make a
decision on the Nanjing leg until late on Monday.
The decision may rest on the state of
the energy reserves held in the plane's batteries.
China's air traffic authorities would
like the team to start the sixth leg before dawn. But if the reserves are
marginal then Solar Impulse will be held in Chongqing until the batteries can
be charged.
The problem with this scenario is that
poor weather is forecast in the Chongqing region in the coming days, and if
Solar Impulse does not leave straightaway, it could be delayed for perhaps a
week.
Solar Impulse took off from Mandalay
International Airport in darkness at 03:36 local time, Monday (21:06 GMT
Sunday). Leg five is long one - about 1,375km - and is expected to take roughly
19 hours.
It would see Solar Impulse landing
around midnight local time at Chongqing Jiangbei International Airport.
