Land shortages in Japan, which have complicated the search for sites for Tokyo's long-required third international airport, may be side-tracked if the proposals of the Mega-Float consortium receive government approval.

Shipbuilders and heavy engineering feature strongly in the consortium of no fewer than 17 major Japanese industrial companies, including such names as Ishikawajima-Harima, Kawasaki, and Mitsubishi HIs, and Nippon Steel Corporation. The practicality of a floating airport is currently being proved by operational trials of a scaled-down 1,000 meter long experimental model assembled in Tokyo Bay. Proof-of-concept flights by light commuter aircraft, including a Dornier Do 228 and Britten-Norman Islander, began earlier this month.

Construction of the experimental floating airport, from an $11.4 billion budget, followed three years of research from 1995 into large structures with lifetimes of over 100 years, using an initial experimental model measuring 300 x 60 meter, and 2 meters deep. A steel-pile mooring system was developed which accommodated tidal and other sea movements, and offered limited impact from earthquake threats. The larger experimental model now under test has a useable runway length of 900 meters, and a parking area at one end of 120 meters width, resulting in an overall area of 8.4 hectares.

Mega-Float has designed its first operational floating airport with a length of 3,000 meters, and options for one or two runways, plus terminal facilities. Costs are said to be competitive with those of land reclamation, which is currently Japan's most likely prospect for a new airport. Claimed advantages include vast inner storage and functional space, shorter construction time, easy expansion of existing facilities, and less impact on the natural environment.

By John Fricker