The F16 fighter jet can withstand incredible forces and pressures. Engineers and test pilots have identified a long list of limits that must not be exceeded in flight. Exceeding those limits can result in minor aircraft damage or catastrophic structural failure. One of the most dangerous limits is speed. Speed through the air creates pressure on the aircraft. The faster an aircraft travels, the more pressure the aircraft structure must endure.
Every kid has rolled down the car window and stuck his hand out into the breeze to feel the pressure of the air rushing past at 70 mph. The same thing happens in airplanes: the faster they go the greater the pressure generated by the wind on every surface of the aircraft. The term “wind” is not quite the right way to describe what’s happening since the air isn’t moving – the aircraft is moving through the air. Engineers use the term “relative wind” to talk about the speed and quality of the air as an aircraft
As you might imagine, the air pressure created by “relative wind” moving past a supersonic fighter jet is almost unimaginable. Pilots who have lived to tell of an emergency ejection from an aircraft traveling at speeds of Mach 1 are few and far between. You might compare it to the experience of water skiing at high speed. Falling off a water ski below about 30 mph isn’t that big of a deal. But increase that speed to 40 or 50 mph and you’ll wonder how water could ever be so hard. What if you were plunged – belly buster style – into that water at over 300 mph? Now imagine how it must feel to explosively emerge from the shelter of a fighter cockpit while traveling in excess of 1,000 miles per hour. Death is almost guaranteed. Supersonic shockwaves actually form on the body of the pilot. Arms and legs are flailed, fractured, and flung from their sockets. Skin is torn, ripped or even shredded. Eyelids are blown open and you don’t want to know what happens to the eyes themselves. Protective clothing is useless. The forces at work are immense. Let’s just say you’re going to have a really bad week after you eject at Mach 1.
Whenever an F16 undergoes a major maintenance overhaul, it is a requirement to verify the proper operation of all aircraft systems by conducting a “Functional Check Flight.” One portion of this flight is called the “speed run” or the “Mach run.” The pilot must see to it that the aircraft exceeds Mach 1.6. Prior to this speed the engine control system has not fully utilized all of its mechanisms for controlling the smooth flow of air into the engine. Although the F16 can fly well in excess of Mach 1.6, it is not necessary to do so to confirm that the engine is operating properly.
Several years ago, an F-16 pilot was conducting one of these flights over the Gulf of Mexico just offshore from an Air Force Base in Florida. Having zoomed his F-16 to over 40,000 feet in less than 3 minutes, he leveled off at that altitude and allowed the aircraft to accelerate. He passed quickly through the speed of sound and was quickly on his way to the specified check point of Mach 1.6. On this particular day, the pilot decided to find out just how close he could come to the maximum Mach limit of the aircraft. The aircraft passed Mach 2.0 and the pilot was unable to stop the acceleration before exceeding Mach 2.05. Accident investigators using data recorders on board the aircraft and computer simulations have reconstructed what happened next. The pressure inside the air intake exceeded the limits established by the engineers who built the aircraft and engine. The face of the engine, constructed primarily of titanium, collapsed while spinning at nearly 20,000 RPM. This resulted in a spontaneous titanium fire, which burned at temperatures far beyond the melting point of most metals. If you’ve ever seen a strip of magnesium burning in a science class experiment, magnify that flame by 10 times and you’ll know what a titanium fire looks like. The engine that had propelled the jet to twice the speed of sound had become a plasma-cutting torch. The aircraft was cut cleanly in half in less than a second leaving the nose of the airplane tumbling violently and the tail section falling like a leaf. The pilot had no other choice but to eject before his cockpit literally disintegrated around him.
The ejection seat functioned properly and the pilot left the cockpit cleanly. The wind forces and shock waves dislocated his ankles, knees, hips, shoulders, elbows, and wrists. The skin on his chest was ripped open. His helmet, visor, and oxygen mask protected his head from major trauma but the skin on his cheeks was torn in several places. The water flotation device designed to automatically inflate around his neck was severely damaged in the ejection. An emergency locator beacon activated when the ejection seat left the aircraft and rescue helicopters were scrambled to locate the pilot. They found him with his head halfway into his one-person life raft clearly indicating that he had survived the ejection and the 15-minute descent to the water in his parachute. The life raft was tethered to his parachute harness and he somehow managed to get his head over the side. But there was water pooled inside the raft and, unable to use his arms or legs, the pilot drowned in his own life raft.
The pilot’s funeral was held the following week. Out of respect for his widow and fatherless children, the other pilots in the unit buried him as a hero.
But they remember him as a fool.
