WASHINGTON (AP) _ During the flight of Payne Stewart's Learjet, the senior military officer involved in monitoring its course consulted the Defense Department's written guidance for the destruction of uncontrolled airborne objects, a Pentagon official said Tuesday.

Pentagon spokesman Kenneth Bacon also said that shortly before the Learjet crashed Monday, an officer on the Joint Staff at the Pentagon raised the question of what actions the military might be asked to take if the business jet were to suddenly veer from its steady northerly course.

Bacon said the question may have been raised by Navy Vice Adm. Scott A. Fry, the Joint Staff director of operations, who was monitoring the Learjet's path on radar in the National Military Command Center in the Pentagon.

``Admiral Fry or someone working with him said, 'You know, if this thing suddenly veers off course and heads to Chicago, we'll have some really tough decisions to make.' It was that type of thinking,'' Bacon said. ``It was not saying, 'OK, let's get ready.' It never got to that point.''

Several unarmed Air Force and Air National Guard fighter jets were directed toward the plane to observe and try to establish contact. Bacon said Tuesday that near the end of the drama, two armed Air Force F-16 air defense jets from Fargo, N.D., were sent aloft briefly but did not reach the Learjet before it crashed.

Bacon said the determination was made early in the Learjet's 1,400-mile flight that it was headed toward a sparsely populated region and therefore no drastic actions would be required.

The spokesman said there are no written Pentagon instructions for destroying a manned civilian aircraft in flight. He said extreme measures were not even a theoretical consideration until the Learjet neared the point when military officers calculated it was about to run out of fuel.

Bacon said he reviewed the sequence of events in a telephone conversation Tuesday with Navy Vice Adm. Herb Browne, the deputy commander in chief of U.S. Space Command at Peterson Air Force Base, Colo., who was in charge because the space commander, Air Force Gen. Richard Myers, was at the Pentagon. Using radars, satellites and other means, Space Command tracks all objects in U.S. airspace and in outer space.

``As they reached the point where they figured the plane was running out of fuel, in the next half an hour to an hour, obviously the question of what do we do if it veers off course became more urgent than it was early on in the operation,'' Bacon said.

``One of the things Admiral Browne did was check the Joint Staff regulations that deal with destruction of derelict airborne objects to find out what was required. But the conversations about action to take never really went beyond the sort of `what-if' that I gave you. You know, `what if' it suddenly veers off course, then we'll have really tough decisions to make. Those decisions were not made.''

The regulation Bacon referred to, dated July 31, 1997, is titled ``Instructions for Destruction of Derelict Airborne Objects.'' It cites as examples unmanned balloons, moored balloons, kites or unmanned nonnuclear rockets or missiles. There is no specific reference to aircraft, civilian or otherwise.

The language most relevant to Monday's incident says, ``For unmanned derelict airborne objects that become a hazard to domestic air navigation or a threat to domestic ground facilities or public safety, military personnel may be required to perform surveillance and-or destroy the unmanned derelict airborne objects.''

The regulation requires that the secretary of defense approve any request for destroying airborne objects over U.S. or international airspace. Bacon said that if the object were a civilian plane the president would have to be notified.