AT 9:16 a.m. on Jan. 6, a Canadian Forces C-130 transport plane lumbered into the air from Ferihegy Airport, near Budapest, Hungary. During the next three hours the plane traced a huge, misshapen figure-eight in Hungarian airspace, varying its altitude from 1,500 to 4,900 meters as it flew. This flight was the first test of procedures for the scheme of mutual surveillance overflights known as ``open skies.'' The plane carried no cameras or special radar: ``We saw what we could out of the aircraft window,'' says a Canadian diplomat. But the test was judged a complete success, demonstrating that inspection overflights could be set up safely and fast.
Open skies now looks as if it might become reality. At this week's Ottawa conference of NATO and Warsaw Pact foreign ministers, other issues had center stage: notably, a new structure to manage German reunification, and agreement on reducing US and Soviet troops in Europe. But the ministers also agreed that barring unforeseen complications they should sign an open skies pact in Hungary in May.
Canadian Minister for External Affairs Joe Clark says the concept had achieved a ``political launch,'' though many details still need to be negotiated.
Thus, an idea first proposed in the 1950s by President Dwight Eisenhower, is coming to fruition in an era of more favorable superpower relations.
In today's world of spy satellites, the concept of surveillance overflights seems old-fashioned, like black-and-white TV or big cars with fins. But real open skies would be useful for two main reasons, experts say.
First, it would be a tremendous confidence building measure for Warsaw Pact and NATO nations to allow the other guy to fly around their territory at will. The new openness in East-West relations would have a literal manifestation.
Second, it could indeed yield valuable insights into the disposition of military forces. ``There is information you can get from airplanes you can't get from satellites,'' says the Canadian diplomat.
With airplanes, it's easy to change lenses or zoom in for a closer look at a suspect spot. Planes can move on short notice, and are easier to repair or replace than systems in space.
Spy planes are also much cheaper than spy satellites. Scanning Central Europe with planes would cost about 1/20th the amount of scanning it from space.
This cost effectiveness makes open skies attractive to smaller alliance members. It would put big-league surveillance capabilities within their reach. Small nations could pool their resources for extra economy - the Netherlands and Belgium are exploring the possibility of establishing one Benelux unit for the purpose of open skies monitoring.
The Soviet Union wants to go even further, and create a joint NATO-Warsaw Pact fleet of surveillance planes. Flight crews and observers of these planes would, similarly, be of mixed nationality. This proposal has drawn criticism from NATO nations that want alliances to keep separate planes.
Nations should give 16 hours notice before flying over to begin an inspection tour, under NATO's proposal. The crew would file a flight plan. The nation being surveyed would have 24 hours to inspect the plane to make sure it contained no proscribed equipment, and could place an observer on flights.
Points still in dispute include:
Data sharing. The Warsaw Pact position is that nations joining open skies should share data from overflights with the others. NATO wants members of each alliance to decide among themselves how to distribute data.
Number of flights. Both sides have agreed on annual ``quotas'' of flights - but they have not said how large that quota will be. NATO has proposed that larger nations be subject to more flights. The Warsaw Pact has called generally for equality between the alliances in flight numbers.
Sensor types. A list of allowed sensors has yet to be agreed to. NATO says it wants to prohibit devices that can pick up ``signals intelligence'' - radio communications and the like. Warsaw Pact nations say they do not want overflight planes to be capable of transmitting their surveillance data by radio.