KC-135 Pressure Test Explosion

[Hubris Boy]

This is what happens when you don't pay attention and don't read the manual.

A KC-135 was being pressurized at ground level. The outflow valves, which are used to regulate the internal pressure of the aircraft, were capped off during a 5 year overhaul and never reopened. The post-accident investigation revealed that a civilian depot technician, who "had always done it that way," was using a homemade gauge, and no procedure.

The technician's gauge didn't even have a max "peg" for the needle, and so it was no surprise he missed it when the needle went around the gauge the first time. As the technician continued to pressurize the aircraft, and the needle was on its second trip around the gauge, the aircraft went "boom" - the rear hatch was hurled over 70 yards, and came to rest behind a blast fence.