Nation: Sky Jams

NASA advises pilots: Look out!

The collision of a Boeing 727 and a tiny Cessna over San Diego that killed 144 last September raised a disturbing question: How often do planes come harrowingly close to each other in the crowded U.S. skies? In an unpublished report now being circulated among Government and industry aviation experts for comment, the National Aeronautics and Space Administration supplies some answers, and they are not reassuring.

Between July 1, 1976, and Nov. 30, 1978, NASA collected 2,856 confidential reports from pilots describing near mid-air collisions, 65% of them...