Boeing Begins Certification Testing on 737 Performance Improvements [video]

SEATTLE, Nov. 16, 2010 /PRNewswire/ -- A Boeing (NYSE: BA) Next-Generation 737-800 in the new United Airlines livery successfully completed its first test flight late last week, signifying the start of certification for a package of 737 performance improvements. Testing and certification will continue through April 2011. Aerodynamic and engine changes included in the package will reduce fuel consumption by 2 percent. Boeing is phasing the changes into production mid-2011 through early 2012.

One percent of the savings comes from reducing resistance as air flows around the airplane. The upper and lower anti-collision lights change from round to a more aerodynamic, elongated teardrop shape. Wheel-well fairings are re-contoured to smooth the air flow near the main landing gear. A redesign of the environmental control system, exhaust vent and streamlined wing slat and spoiler trailing edges round out the aerodynamic changes.

CFM is introducing the new CFM56-7BE engine enhancement program to coincide with Boeing's airframe changes. Low- and high-pressure turbine modifications will result in a 1 percent reduction in fuel consumption. In addition, Boeing is optimizing the engine's primary nozzle and plug. Together, the changes result in cooler-running engines that may provide up to 4 percent lower maintenance costs.

Boeing's continuous efforts to improve the Next-Generation 737 family have resulted in an accumulated 5 percent gain in fuel efficiency since the first airplane was delivered in 1998. The new improvements will give operators an airplane that is 7 percent more efficient than the first Next-Generation 737s delivered.

In late October, Boeing delivered its first two Next-Generation 737-800s with the new Boeing Sky Interior. The interior features new cove lighting and curving architecture that create a more open feel in the cabin. Updated sidewalls and window reveals add a modern feel, and larger stowage bins enable passengers to store more luggage while giving them more headroom. Deliveries to new operators continue each month.


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As he stepped onboard the Next-Generation 737 that is fitted with numerous aerodynamic improvements to reduce fuel burn, Boeing engineer David Mathews remembered all the work that went into just one of the design changes.

"There were times we didn't think it was going to happen," he said.
Mathews and his colleagues spent years working with a supplier to come up with a new, more aerodynamic anti-collision light. The light, mounted on the top and bottom of the fuselage, had to meet strict federal regulations for light intensity.

"It's more than just two wires and a light bulb," said Mathews. "We tested numerous iterations. If the aerodynamic improvements weren't there, we would start all over again."
There was also the added challenge of coming up with a new design without changing the forces on the proven 737 fuselage or drastically altering the established production process at the Boeing factory in Renton, Wash.

"All those kinds of things have to be considered," Mathews said.
While Mathews worked on the anti-collision light, other teams of Boeing engineers went through the same painstaking process to further improve other portions of the Next-Generation 737 airframe.

The result is a package of performance improvements that includes:

• Wheel well fairings re-contoured to smooth the air flow near the main landing gear
• Environmental control system exhaust vent re-designed
• Slat and spoiler trailing edges streamlined

These modifications - which reduce resistance as air flows around the airplane - are projected to add up to a 1 percent reduction in fuel burn.

At the same time, CFM is introducing the new CFM56-7BE, an enhanced version of its already fuel-efficient engine. Boeing predicts all of the changes combined will translate into a 2 percent fuel burn reduction. That would mean saving an average of $120,000 per airplane, per year, based on current fuel prices. Airlines will not have to pay extra for the improvements, which will also reduce the airplane's carbon footprint.

"A small change here, a small change there, it all adds up," said Mathews. He and his team finally decided on a tear-shaped design that is smaller and more streamlined, while still projecting the same light intensity.


Now, the Boeing Test & Evaluation team takes over to put all of the changes to the test.

"We have to validate to the customers that we are going to get the performance improvements that we predicted through all the design analysis," said Erin Henderson, a ground operations engineer. "The other thing we have to do is certify all of these improvements to the FAA (Federal Aviation Administration) to prove they're safe for flight and they're safe to sell for our customers."

Recently, the team conducted its first test flight on the Next-Generation 737, which is painted in the new United Airlines livery. There will be many more tests in the months to come before the modifications are phased into the Next-Generation 737 production line in mid-2011.
For David Mathews, who got the chance to fly onboard the first flight, all the hard work has been well worth it.

"When you come up with a fine piece of equipment and it goes on the airplane, it's very rewarding."