Boeing Revises 737 Max Fuel-Burn Advantage Upward

 - November 4, 2013, 11:40 AM
Boeing revised upward its estimated fuel-burn advantage for the 737 Max over the current 737-800NG. (Photo: Boeing)

Boeing said it has completed aerodynamics, engine and weight audits that together have given it a clearer picture of the future operating performance of the new 737 Max. The manufacturer now says the re-engined narrowbody will burn 14 percent less fuel than today’s 737-800NG, one percent better than it previously estimated.

Boeing executives announced the updated fuel-performance estimate during a teleconference with reporters on October 29. The manufacturer earlier achieved firm configuration and systems definition milestones for the 737 Max 8 fitted with new CFM Leap-1B engines. In July, upon completing firm configuration, or defining the design requirements, Boeing said the jet would be 13 percent more fuel efficient than the current 737NG.

Michael Teal, 737 Max chief project engineer, said half of the 1-percent gain in fuel savings over Boeing’s previous estimate comes from an aerodynamic improvement that is realized when integrating the new engines and nacelles with the wing. “On the NG, there are some characteristics of how shock waves work on the inboard wing that actually cause drag,” he said. “The integration of the engines with the wing has enabled us to minimize that shock wave, which improved the drag.” The other half percent relates to the aerodynamics of the 737 Max’s “advanced-technology winglet,” which Boeing already credits for 1.5 percent in fuel savings, and the completed engine system audit.

Teal said the 14-percent fuel-burn advantage applies to 737 Max 7, 8 and 9 versions. He repeated Boeing’s assertion that the Max 8, which the company expects will enter service in the third quarter of 2017, will provide an 8-percent operating cost advantage per seat over “the competition,” a reference to the Airbus A320neo. “While it is true that the Max will experience some weight growth due to the larger, more optimized engine that gives us the 14 percent [fuel-burn advantage]…the Max will remain the lighter airplane because of our overall structural efficiency,” Teal declared.

Boeing will introduce an enhanced digital flight-data acquisition unit and a new network file server, both supplied by Teledyne Controls, to provide a centralized data-collection system with more storage capacity for maintenance data on 737NGs, followed by the 737 Max. It will incorporate offboard broadband connectivity on 737NGs beginning in 2015 so that airlines can prepare for maintenance actions ahead of the aircraft landing.

Some built-in test equipment (Bite) will be brought into the 737 flight deck to accelerate maintenance; at present technicians gain access to fault data in the forward electronics bay. Boeing tested some of the new systems on its 737-800 “ecoDemonstrator” testbed last year. “Through careful testing and selective application [on] the next-generation 737 before the Max enters service, we will ensure that these systems are ready to enhance the management of the customer’s fleet,” Teal said.

Boeing reports orders for more than 1,600 copies of the 737 Max from 28 customers. Keith Leverkuhn, 737 Max program manager, said the revised fuel-burn estimate should enhance the aircraft’s appeal. “We went to the market with less than 14 percent,” he said. “Fundamentally we’re really pleased with the market response to the Max and we can only see this adding to it.”