Engines
CFM Certifies Leap 1B Engine Durability Kits
Engine maker boosts high pressure turbine and fuel nozzle reliability on 737s
CFM International Leap 1B engine
CFM International has certified reliability modifications on the Leap 1B turbofan that powers Boeing’s 737 Max airliners.

CFM International has completed FAA and EASA certification of a high-pressure turbine (HPT) durability kit for the Leap 1B engine and expects these to be delivered with new production turbofans from early 2027. At a press briefing in London on Sunday, the manufacturer also reported that during the second half of this year, it expects to complete approval for a reverse bleed system (RBS).

According to Tom Levin, vice president for CFM commercial programs, the modifications are a key aspect of efforts to increase time on wing for Boeing 737 Max operators. The HPT kit is already installed on around 40% of the Leap 1A engines that power the rival Airbus A320 narrowbody, and 70% have the RBS, which cools fuel nozzles to reduce coking on these parts.