The sun-powered plane Solar Impulse 2 has made a successful test flight in Hawaii, where it has been grounded for repairs on its round-the-world trek, the Swiss-based project said Saturday.

"The first Solar Impulse 2 maintenance flight took place on Friday 26 of February (and) was uneventful. The plane took off from Kalaeloa airport at 4:32PM UTC [GMT] with our test pilot, Markus Scherdel, in the cockpit, and landed at 6:05PM UTC," it said on its blog.

Lasting an hour and a half and reaching an altitude of 8,000 feet (2,400 metres), the flight enabled technicians to run checks on the stabilisation and cooling system, "which both performed superbly," the project said.

The plane completed nearly half of an unprecedented round-the-world journey without using a drop of fuel before battery damage during a gruelling five-day leg from Japan to Hawaii in July forced its grounding.

On December 20, Solar Impulse spokeswoman Alexandra Gindroz told AFP that, after securing funds to complete the repairs and finance the next phase of operations, the plane would be ready to fly again by April 20.

The aircraft took off from the United Arab Emirates (UAE) on March 9, powered by 17,000 solar cells, with the aim of promoting renewable energy through a round-the-world flight.

Pilots Andre Borschberg and Bertrand Piccard have divided the flying throughout the groundbreaking project.

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UNITED TECHNOLOGIES