Rumor mill was in full tilt

The air defenses did not work, the border guards were caught flat-footed, but one thing did work when flier Mathias Rust arrived here: the rumor mill. On Friday morning, several Soviet office workers say, Mr. Rust's landing of a private plane in Red Square on Thursday was the main topic of conversation. ``We started hearing rumors about it when we arrived at 10:00,'' said one. By lunchtime, the grapevine was saying that the plane had come from Finland.

The nationality of the flier was a subject of some dispute. Most informal news sources seemed, however, to have agreed that Mr. Rust was a Westerner. ``Poles do not fly into the Soviet Union,'' one person remarked when asked if the flier might have been East European.

The sources of the rumors could have been Western radio stations.

In any case, there is little doubt who in the Western community knew about the plane first. It was the nanny network - foreign women, many of them students of Russian, and some of them married to Russians, who look after children of diplomats and journalists.