Grumman Test Pilot Shoots Himself Down
September 21st, 1956, Grumman company test pilot Tom Attridge showed up for another day of work as a test pilot for Grumman Iron Works. His mission for the day was to take up a Grumman F11F Tiger, bring it up to the speed of sound (Mach 1.0) at twenty thousand feet, then push the nose over into a sustained 20-degree dive down to 7000 feet in altitude. During this descent, Tom would fire off a few short bursts of cannon fire as part of the flight test profile, and upon reaching 7000 feet, the test was over. A literal walk in the park.
After achieving the predetermined altitude for the test, Atteidge bumped up the throttles and accelerated to the speed of sound, then pushed the nose forward to 20 degrees nose down to achieve the appropriate test profile. As Tom pushed forward, at 0.5Gs in a supersonic descent, he fired two bursts from the Tiger's 20 mm cannon. Unknowingly, poor Ol’ Tom was now in a loose formation with his own cannon projectiles somewhere overhead his canopy, and as he reached 7,000 feet over 11 seconds later, commencing his pull-out, his jet was immediately struck multiple times. One shell cracked his windscreen, and the other was ingested by the engine, shredding the compressor blades. Tom had subsequently flown underneath the trajectory of his own cannon rounds, and while pulling out, poor Tom flew unknowingly, and squarely into his own stream of projectiles, effectively, and most unfortunately shooting himself down in the process.
Now very much the innocent victim of his own actions, Tom managed to limp his stricken Tiger back to the Grumman airfield where on short final his engine finally gave way and Tom was forced to put his aircraft down into the trees.
Poor Tom, suffered a very bad day at work, thankfully and luckily only receiving minor injuries and a bruised ego after his unplanned trip to the woods, It was quickly determined that Grumman company test pilot Tom Attridge had inadvertently and again, most unfortunately shot himself down with his own gun.
We were TDY in Lybia for gunnery training in the F-D. After firing while pulling out, you would also jink so you would be out of the path of any ricochet. We caught one in the leading edge of the right wing. I asked the guy in front if he had done a good walkaround and didn’t see the bullet hole.
I dictate into my phone and it doesn’t translate correctly all the time. The word blood should have been bled. :-)
Not sure what the confusion is but as some of you pointed out, yeah the cartridges were ejected horizontally at the same forward speed as the aircraft but they quickly fell behind due to drag. Similarly, while the initial velocity of the projectiles was the plane speed plus the muzzle velocity, all that extra kinetic energy was blood off quickly by aerodynamic drag and soon the projectiles were merely going at terminal velocity, not nearly as fast as muzzle velocity but enough to do some serious damage. :-)
I don’t think any of those cannon rounds were explosive. Explosive projectiles are possible, but they are very unusual. I’m not sure where the idea that these particular rounds were explosive came from.
Projectiles, not cartridges folks. Huge difference. The Tiger had four Colt MK-12 20mm cannon mounted alongside and below the air intakes, with shell casings ejecting below and just forward of the wing roots. Keep in mind this was still the early days of supersonic flight, stuff like this is why test pilots got the “big bucks.” “Hey Tom, do this and see what happens.”
First, the company name was Grumman Aircraft Engineering Corporation, not Grumman Iron Works.
Which airfield was he using? Presumably Calverton rather than Bethpage or Patuxent River.
Leave a comment