WASHINGTON – An Air National Guard pilot who fired on a New Jersey school during a training exercise was to blame for the incident, but poorly designed controls in the F-16 also played a role, the Air Force concluded Friday.

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.