Your Friends Name:
Your Friends Email:
By Bernard Choi
The airplane starts accelerating down the runway. In the flight deck, Captain Paul Stemer feels the weight of the situation.
"It's a lot of mass, a lot of energy. I have to stay ahead of it."
It's up to Capt. Stemer to command RC521, the second 747-8 Freighter, into defying gravity and lifting more than 1 million pounds into the air. It's a feat neither he nor any Boeing Flight Test pilot before him has ever attempted.
While the airplane gathers speed, 100 knots, 120, 140, now 160 knots, the amount of available runway quickly evaporates.
RC521 still needs to go faster before Capt. Stemer can command the elevator to rotate the airplane, increasing the wing's angle of attack and generating lift.
"With only 7,000 feet (2,133 m) of a 15,000-foot (4,572 m) runway remaining, it's obvious the margin of error is small," says Capt. Stemer.
"It's a big deal for us and as an engineer it's a badge of honor."
Andy Hammer, 747-8 Flight Test manager
This moment makes clear why Boeing engineers and technicians spend months in the California desert conducting exhaustive tests to certify the new airplane.
"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."
Boeing engineers stretched the fuselage of the iconic 747 to create the new 747-8 Freighter. The bigger airplane boasts a designed maximum takeoff weight (MTOW) of 975,000 pounds (442,253 kg), compared to the 875,000 pound (396,900 kg) MTOW of its predecessor, the 747-400 Freighter.
To prove the airplane is capable of taking off with such a heavy burden, the Boeing Test & Evaluation team loaded RC521 with plenty of fuel and stacked dozens of steel plates, each weighing 3,000 pounds, into the cargo hold.
When it was all packed and loaded, the airplane weighed about 1,005,000 pounds (455,860 kg).
"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."
That brings us back near the end of the runway. Only about 4,500 feet (1,372 m) remain but Capt. Stemer is confident.
"Airplane and systems control and operation are excellent and now it's 'all go'".
With the new GEnx-2b engines providing the thrust, RC521 lifts off the ground and soars into the California sky.
"It's incredible to think that people, the men and women of the Boeing Company, together with the partners around the world can build such a magnificent flying machine that is capable of lifting over 1 million pounds into the air," says Capt. Stemer.
After a four-hour flight, Capt. Stemer and the U.S. Federal Aviation Administration's Capt. Bob Stoney landed RC521 safely back in California, completing the flight that began with the heaviest takeoff in Boeing's history.
"It's a big deal for us and as an engineer it's a badge of honor," said Hammer. "It's a testament to the initial design that it is doing more than was initially envisioned."