The report, obtained by The Associated Press, also disclosed that there have been three other incidents this year in which an F-16 pilot unintentionally fired during nighttime strafing missions. It did not say where and when the other incidents occurred, but the report noted that, like the New Jersey case, no one was hurt.
The report called the Nov. 3 New Jersey incident an "unfortunate and unintentional mistake." It said the pilot never intended to strafe the Little Egg Harbor Township Intermediate School and suggested computer software changes to the aircraft control systems to prevent another incident.
In an F-16, the same trigger is used to produce a laser marker to focus on a target and to fire the gun in certain modes of operation.
"In my opinion, using the same trigger for both laser marking and firing the aircraft's gun significantly increases the risk of human error and an unintentional gun discharge," Col. Kevin W. Bradley, the president of the Accident Investigation Board, said in the report.
The pilot was identified as Maj. Roberto Balzano of the 113th Wing of the District of Columbia National Guard, based at Andrews Air Force Base in Maryland. The report said his commander will determine if any punitive or administrative action should be taken, and whether any retraining is necessary. Balzano has more than 2,000 hours of experience flying planes, 975 hours of which were in the F-16s.
Air Force spokesman Lt. Col. Mike Milord said military officials would not answer any questions regarding the incident until meeting with residents Friday evening in Little Egg Harbor Township.
Balzano, referred to in the report as the "mishap pilot," or MP, was verifying his aircraft position in relation to his intended ground targets on the Warren Grove Gunnery Range in southern New Jersey, 17 miles northeast of Atlantic City. The school is about four miles from the range.
"Unfortunately, the MP forgot that his aircraft's air-to-ground gun mode was selected and armed ready to fire. The MP immediately realized his error when the aircraft gun's discharged," the report said.
Balzano was on a nighttime training sortie conducting basic surface attacks at the range. A briefing session was held before the mission and Balzano was cautioned not to use his laser marker with the air-to-ground gun mode selected and the gun armed, the report said.
However, shortly after 9 p.m., Balzano was flying at approximately 7,000 feet over the range when he pulled the trigger, firing 27 rounds of 20mm ammunition. Eight of the 2-inch lead rounds punched through the school's roof, knocking down ceiling tiles. At least one rounded struck a child's desk, and others scuffed the asphalt in the parking lot.
Balzano immediately told the control tower something had gone wrong, scrapped his mission and returned to Andrews.
The range reopened Thursday. Sen. Frank Lautenberg, D-N.J., had called for the range to be closed until the investigation was completed, and officials shut it down.