LEAP-1B

Boeing and CFM International have started flight testing of the LEAP-1B engine, which will power the 737 MAX.

A modified 747 flying testbed-equipped with the LEAP-1B engine was flown from GE Aviation flight test operations in Victorville, California, US, on 29 April.

During the 5hr 30min first flight, the engine completed multiple aeromechanical tests at various altitudes.

The tests are said to be a major phase of the programme, to secure engine certification in 2016 with plans to deliver the first Boeing 737 MAX in 2017.

CFM International executive vice president Allen Paxson said: "The LEAP engine has been doing incredibly well throughout a very rigorous ground and flight test programme.

"Results to date are right in line with what we predicted and where we wanted this engine to be."

The flight test programme will soon evaluate engine operability, stall margin, performance, emissions and acoustics.

The programme will also validate advanced technologies in the engine, including the woven carbon fibre composite fan, the twin-annular, pre-mixing swirler (TAPS) combustor, ceramic matrix composite shrouds and titanium aluminide blades in turbines.

"Results to date are right in line with what we predicted and where we wanted this engine to be."

Boeing Commercial Airplanes 737 MAX programme vice-president and general manager Keith Leverkuhn said: "With this major engine milestone and the test results to date, we continue to be confident that the LEAP-1B-powered 737 MAX will provide our customers with the most fuel efficient, reliable and maintainable airplane in the single-aisle market.

"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."

Boeing has so far logged 2,724 orders for the 737 MAX from 57 customers worldwide.

CFM is currently testing 26 LEAP engines with ten additional engines in various stages of final assembly.

Covering all three LEAP engine variants, the programme comprises 28 ground and CFM flight test engines and 32 flight test engines for aircraft manufacturers.

Image: The LEAP-1B engine was tested on a modified 747 flying testbed. Photo: courtesy of CFM International.