Flying wing debris collected
By Jan TenBruggencate
Advertiser Science Writer
MANA, Kaua'i — Most of the drifting wreckage of the Helios solar flying wing was recovered from the Kaulakahi Channel between Kaua'i and Ni'ihau by sunset yesterday, although it was unclear how much of the plane had sunk.
A Navy boat, a landing craft from Ni'ihau Ranch and a helicopter from Ni'ihau Helicopters participated in the recovery. Debris was to be hauled to the Pacific Missile Range Facility for assessment, said Navy spokeswoman Agnes Tauyan.
The unmanned solar-powered aircraft appeared to break up in flight before its wreckage fluttered out of the sky Thursday, NASA officials said. It had taken off from the runway at the Pacific Missile Range Facility shortly after 10 a.m. Thursday and was in an altitude-gaining pattern between Kaua'i and Ni'ihau.
The craft was 3,000 feet above the ocean's surface when it began breaking apart for reasons still not determined, said Alan Brown, spokesman for NASA's Dryden Flight Research Center in Edwards, Calif.
Helios was a high-tech and expensive aircraft. Brown said the solar photovoltaic cells in its 247-foot wing were valued at $10 million and its airframe at another $5 million. Brown had no estimate for the value of an experimental high-altitude fuel-cell power system that had been designed specifically for Helios.
The plane was to test that fuel cell at altitude for the first time Thursday night, after the power of the solar cells had taken the plane to about 50,000 feet.
Shifting winds delayed the takeoff Thursday. Helios had been prepared to take off from one end of the runway when officials determined that the winds had changed and were blowing from behind it. They towed the craft to the other end of the runway so it could take off into the breeze. One report indicated that the wing dipped dramatically to one side immediately after takeoff, but then appeared to fly normally.
Helios carried the heaviest load it has ever handled. The plane weighed just 1,600 pounds in 2001 when it set a world altitude record of 96,863 feet, but the additional weight of two 180-pound hydrogen tanks, the fuel cell, compressor and associated plumbing brought its total weight to more than 2,300 pounds, Brown said.
The plane flew for 29 minutes, reaching a point roughly midway between Kaua'i and Ni'ihau.
The Coast Guard issued a notice to mariners to avoid the crash site, whose coordinates were listed as 22 degrees 5 minutes north, 159 degrees 56 minutes west.
A helicopter with a camera was following Helios, but it didn't get photos of the breakup, and it was unclear what video images were available, Brown said. But the plane did send electronic data throughout its flight, and that information has been "saved and impounded" for use in the investigation.
A five-member crash investigation panel was named yesterday. Its members are Thomas E. Noll, chairman, Langley Research Center, Hampton, Va.; John M. Brown, National Oceanic and Atmospheric Administration's Forecast Systems Laboratory, Boulder, Colo.; Stephen D. Ishmael, Dryden Flight Research Center, Edwards, Calif.; Marla E. Perez-Davis, Glenn Research Center, Cleveland; Geary C. Tiffany, Ames Research Center, Moffett Field, Calif.
Brown said it was too early to know what caused the plane to begin breaking up. One suspect —though certainly not the only one — is the single composite beam that supported the entire, bendy wing. Brown said there was no evidence it was struck by a flying object, but he could not say whether it had been damaged at some point earlier, was overloaded by weather conditions or had been weakened by the stress of multiple flights.
The spar was built of carbon fiber. It was wrapped in other high-tech materials for additional strength where needed.
AeroVironment, the firm that designed and built Helios, said further testing this summer will use its predecessor solar plane, Pathfinder-Plus. The firm said it and NASA hope to build another Helios or a similar aircraft, though Brown said NASA at this time does not have the money to build a new plane.
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