RC521 Flies More Than 25,000 Pounds Over MTOW

Under normal circumstances, its inadvisable to attempt a departure well over maximum takeoff weight, but certification is not "normal circumstances." And so, Boeing engineers last week loaded up the second 747-8 test aircraft to more than 25,000 pounds over its 975,000 designed maximum weight, and pointed it down the runway.

File Photo

It wasn't that easy, of course. Boeing said in a prepared report that weeks of planning went into the test. "In flight test, we test the airplane's capabilities above and beyond the normal operating conditions," says Andy Hammer, flight test manager for the 747-8. "This way, we can clearly demonstrate to the customers, the regulatory agencies, and the passengers that the aircraft is capable of performing at these levels."

For the test, RC521 was first filled with literally tons of fuel. Then, dozens of steel plates weighing 3,000 each were loaded into the lower cargo hold. The result was an airplane that weighed 1,005,000 pounds when it started down the 15,000 foot runway. "It's a lot of mass, a lot of energy. I have to stay ahead of it," said Captain Paul Stemer as the runway in front of him rapidly vanished.

Engineers Load Steel Plates Boeing Photo

Then, with about 4,500 feet of pavement left, the airplane lifted into the air. "A lot of planning went into this," Hammer said. "We had to demonstrate that the wheels, tires and brakes are in position to support it. We had to demonstrate the performance of the aircraft, from an aero perspective, is okay."

After getting airborne, Stemer flew the heavy 747-8 for 4 hours before landing back at the California airport. The flight is now in the books as the being the heaviest takeoff in Boeing history.

FMI: www.boeing.com