Boeing has two new planes, the 747-8 Intercontinental and the 747-8 Freighter. They are testing all their systems now. That includes the brakes, which means a rejected takeoff test with a fully loaded plane. This is how they did it:
1. They took a 747-8 Freighter to a long runway in California.
2. They loaded the plane to maximum capacity. That means have it full of fuel and cargo up to its takeoff weight limit: 975,000 pounds—308,000 pounds of that is the 747-8's payload capacity.
3. They took off the set of brakes and installed 100% worn-out brakes.
4. Then Captain Kirk Vining took the aircraft to the beginning of the runway and put its four General Electric GEnx-2B67 to full throttle, each of them delivering 66,500-pound-force to a combined force of 1,184 kilonewtons.
5. After a few seconds, the aircraft reached 200 miles per hour, almost the point of no return. At that time, Captain Vining slammed the brakes hoping for the best. No air braking is allowed. This is a job exclusively for the brakes.
And the best happened: The 747-8 Freighter stopped even before it was planned, its worn-out braking discs hot bright orange—reaching a temperature of 1400 degrees Celsius or 2552 degrees Fahrenheit— and no signs of fire, just some smoke. In fact, the firefighting crew was not supposed to throw water on the brakes for five minutes just to see if any fire started. It didn't, leaving ruined tires and brakes, but the rest of the aeroplane completely untouched. [Boeing]