The Pentagon's admission that at least five bombs went astray and hit the French Embassy and civilian homes during last month's raid against Libya brings to mind an old mud soldier's warning: "Trying to do precision bombing with an airplane is like trying to do brain surgery with a bayonet."

Retired colonel John B. Keeley -- an infantry officer during the Korean War, a battalion commander in Vietnam, a brigade commander in West Germany and the author of that from-the-ground view -- said bombing by fallible human beings in planes hurtling along at more than 400 miles an hour is bound to be imprecise at times, no matter how smart the crews or the weaponry.

Many fliers, especially those with combat experience, agree. They warn that collateral damage -- the term for killing innocent people and destroying houses in the target zone -- is likely to be more extensive if President Reagan opts for larger bombing raids in the future to retaliate for terrorist acts. The short history of the bombing raids against Libya undersores their point.

The limited Navy bombing during the Gulf of Sidra penetration in March apparently was on target. The wider Air Force-Navy raid against Libya on April 15 killed civilians and destroyed homes despite the great care taken by the air crews and the employment of "smart weapons," including guidance by laser beam.

Limited collateral damage occurred in last month's raid even though the planners were told to select targets big enough to reflect radar beams so that "smart," precision bombs could be employed. This target selection contrasted with the Dec. 4, 1983, bombing of Lebanon when Navy planes had to dive on targets to see them because they were so small. This increased the bombers' vulnerability to ground fire. Two of the 28 attacking Navy bombers were downed over Lebanon compared to one of 25 over Libya (not counting the five Air Force F111s and two Navy A6E bombers that aborted before dropping their bombs).

In the three weeks following the raid against Libyan leader Muammar Qaddafi's compound in Tripoli and air fields and other military facilities, military planners at the Pentagon, Central Intelligence Agency and White House have refined their target folders for an even larger bombing raid against Libya in case Reagan opts to escalate the conflict. The new targets include Libyan oil pumping and storage facilities and the potential weaponry includes cruise missiles with conventional warheads.

The history of the Vietnam air war also suggests Third World nations such as Libya and Syria would turn to their super-power sponsor, the Soviet Union, to upgrade their air defenses if convinced they are about to be bombed by the United States.

Retired Air Force general William W. Momyer, who commanded the Seventh Air Force in Vietnam from July 1966 until August 1968, wrote in "Air Power in Three Wars" that this is what happened after the United States started bombing North Vietnam on Aug. 5, 1964.

"Rather than shocking their leaders and disrupting their war machinery with a concentrated, strategic air offensive," wrote Momyer, "we had merely alerted them the North Vietnamese to start work on what would become a superb air defense system of MiGs, surface-to-air missiles and antiaircraft artillery."