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Boeing and CFM International have begun flight testing of the LEAP-1B engine on a modified 747 flying testbed at GE Aviation Flight Test Operations in California.

LEAP for Boeing 737 MAX makes first flight

At the end of April, Boeing and CFM International initiated flight testing of the LEAP-1B engine on a modified 747 flying testbed at GE Aviation Flight Test Operations in Victorville, CA.

The flight testing is a major milestone in a two-year program that will culminate in engine certification in 2016 and delivery of the first Boeing 737 MAX in 2017. The LEAP (leading edge aviation propulsion) engine is said to have performed well and completed multiple aeromechanical test points at various altitudes during the 5.5 h first flight.

According to Chief Test Pilot Steven Crane, CFM, "These engines are demonstrating a maturity that you don't always see in new products." CFM is a 50/50 joint venture between Snecma and GE.

The LEAP-1B engine is the exclusive powerplant for the Boeing 737 MAX family and is part of “the most extensive ground and flight test certification program in CFM's history.” The first LEAP-1B engine began ground testing on June 13, 2014, three days ahead of the schedule set when the program was launched in 2011. Keith Leverkuhn, Vice President and General Manager, 737 MAX program, Boeing Commercial Airplanes, says the 737 MAX is on track to deliver 14% more fuel efficiency than today's most efficient Next-Generation 737s and 20% more efficiency than the first Next-Generation 737s to enter service.

Throughout May, the flight test program will consist of a comprehensive test schedule that will gauge engine operability, stall margin, performance, emissions, and acoustics. It also will further validate the advanced technologies incorporated in the engine, including the woven carbon fiber composite fan, the Twin-Annular, Pre-Mixing Swirler (TAPS) combustor, ceramic matrix composite shrouds in the high-pressure turbine, and titanium aluminide blades in the low-pressure turbine.

"The LEAP engine has been doing incredibly well throughout a very rigorous ground and flight test program," said Allen Paxson, CFM Executive Vice President. "All of these engines are heavily instrumented, many of them deliberately deteriorated, to calibrate performance and durability in the most extreme conditions. We have successfully completed several major certification tests, including icing, flocking bird ingestion, large-bird ingestion, and even a fan blade-out test. We have passed them all and the results are right in line with what we predicted and where we wanted this engine to be."

To date, the LEAP-1B-powered 737 MAX has accumulated 2724 orders from 57 customers worldwide. The total program encompassing all three LEAP engine variants includes 28 ground and CFM flight test engines, along with a total of 32 flight test engines for the aircraft manufacturers. The LEAP-1A is an option for the Airbus A320neo and the LEAP-1C is the only Western powerplant option for the COMAC C919.

Over a three-year span, these engines will accumulate approximately 40,000 engine cycles leading up to entry into service. By the time this engine enters service, CFM will have simulated more than 15 years of airline service with 60 different engine builds.

CFM officially launched the LEAP engine, which is the company's first all-new centerline engine in nearly 40 years, in 2008. The engine was being designed to bring double-digit improvements in fuel efficiency, emissions and noise, while maintaining the reliability and low cost of ownership of its predecessor, the CFM56 engine family.

In 2011, Boeing selected the LEAP-1B as the sole powerplant for its new 737 MAX, extending a more than 30-year relationship. CFM has been the only engine provider for the 737 aircraft family since the 737 Classic entered service in 1984.

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