Over Milford, New Hampshire – July 13, 1951
On July 13, 1951, a T-33A training jet (#49-943A), took off from Grenier Air Force base in Manchester, New Hampshire, for a training flight to Westover Air Force Base, in Chicopee, Massachusetts. Twelve minutes into the flight, while the aircraft was at 15,000 feet over the town of Milford, the rear third section of the Plexiglass canopy exploded without warning. Pieces of the canopy struck the wings and other portions of the aircraft causing substantial damage, however the pilot and instructor aboard weren’t injured.
The aircraft immediately returned to Grenier Field without further incident. Investigators suspected the cause was due to a malfunction with the cockpit’s pressure regulator and relief valve.
The aircraft was repaired and put back into service.
Source: Air Force Aircraft Accident Investigation Report, #51-7-13-6