'Severe' bending seen in solar craft

By Jan TenBruggencate
Advertiser Kaua'i Bureau

MANA, Kaua'i — The 247-foot wing of the Helios solar airplane bent dramatically, then began flapping before its skin tore and it plunged into the sea, a NASA official said yesterday.

Four of five members of a crash investigation board were on Kaua'i yesterday to attempt to identify a cause for the Thursday crash. There was no indication when the probe would be finished.

"There was severe wing bending and oscillation, then the wing surface ripped and spars broke," said Alan Brown, spokesman for NASA's Dryden Flight Research Center in Edwards, Calif.

Helios was an unmanned experimental flying wing, with propellers and electric motors powered primarily by solar photovoltaic panels under the wing's clear skin.

On its flight Thursday, it was to test a new hydrogen fuel cell that would allow the plane to stay aloft overnight.

Brown said the plane was 29 minutes into its flight, at 3,000 feet above sea level and gaining altitude slowly when the crew of a chase helicopter saw it begin bending and shuddering.

The reason for the sudden loss of stability was not immediately clear, he said. The plane crashed into the sea about 10 miles from Kaua'i.

A recovery effort has picked up 80 percent to 90 percent of the structure of the plane, including both of its hydrogen tanks. But the heavy fuel cell assembly has probably sunk 5,000 feet to the ocean floor, Brown said.

Most of the wreckage was picked up at sea, but some washed ashore in a narrow area not far from the Pacific Missile Range Facility, where Helios took off Thursday morning.

Helios had solar panels valued at $10 million and its airframe cost $5 million, but none are reusable because of the salt water contamination, Brown said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.