The plane that shot Itself down

September 21, 1956. Grumman test pilot Thomas W. Attridge Jr. is flying a pre-production F11F-1 fighter prototype, tail number 138620, at 20,00 feet.

The actual aircraft that he was flying that day: Tail Number 138620

It's a small, quick plane, the first naval fighter to be capable of supersonic speeds, and armed with four powerful Colt 20mm cannon. Attridge finds an empty patch of ocean and enters a dive at 20 degrees. at 13,000 feet of altitude, he fires a four second burst, and then enters a steeper dive, engaging afterburner and breaking the speed of sound. He shoots again, emptying the ammunition belts.

At 7,000 feet he pulls out of the dive, and starts a climb back to altitude. Twenty seconds later the plane suddenly rattles and shakes, and the windshield shatters. Attridge immediately lowers the throttle and slows down to prevent the windshield from caving in completely.  He then turns the plane to land at Grumman's Long Island testing field, maintaining a speed of 200 knots and radioing the field that a bird strike had occurred and that the only damage appeared to be a large gash in the right intake lip and the broken windshield. More concerning, however, the engine wouldn't go above 78% power without severe shaking and roughness.

2 miles out from the runway, at 1,200 feet and with flaps and gear down, it became clear to Attridge that he wouldn't make the runway at that low of a power setting. Raising the power to prevent a crash, the engine started to make a noise like "a hoover vacuum cleaner picking up gravel from a rug." The engine then died completely. The F11F-1 did have an ejection seat, but for some reason (that I couldn't find) Attridge decided to stay with the aircraft. Having no other option (other than ejection), he raised the landing gear, braced himself, and landed in some trees half a mile from the runway, gouging out a path 300 feet long as the state-of-the-art fighter slid along the ground. A fire started, but Attridge was able to cut himself free and was rescued by a helicopter shortly after.

So What Happened?

I think you already have an idea of what happened, so I'll keep this brief. The first four-second cannon burst initially had a velocity well over 2000 mph, air resistance quickly slowed down the bullets to about Mach 1. Right after firing the burst Attridge nosed the plane over and exceeded Mach 1. As he fired the second burst the original burst was still arcing through the sky above him, and as he pulled up he caught up to the bullets! Only three rounds impacted the plane: One in the windshield, one on the right intake lip, and one going into the intake and getting lodged inside of the jet engine's compressor.

The bulled that killed the engine

Attridge shattered his leg and broke three vertebrae in the crash, but returned to flight six months later. He went on to be project manager for LEM-3, the first lunar module rated for human flight, flown on Apollo 9. He then served has Vice President of Grumman Ecosystems, Grumman's environmental management and research division.

The F11F was flown by the Blue Angels for a few years