India’s IndiGo airline, one of the world’s fastest-growing low-cost carriers, said on Friday it will use fuel-efficient LEAP-1A engines from CFM International to power its fleet of 310 new Airbus A320neo, A321neo and A321XLR aircraft. The agreement, one of the largest in CFM’s history, includes 620 new installed engines and associated spare engines, as well as a multi-year service agreement. “This is a pivotal milestone that reflects our long-standing commitment to rapidly strengthen our network both domestically and internationally,” said IndiGo CEO Ronojoy Dutta. “This expansion will serve as a catalyst to boost India’s economic growth and the mobility of its people.”

CFM International is a 50-50 joint venture between GE and Safran Aircraft Engines. CFM started developing the LEAP jet engine nearly two decades ago. The engineers were able to lower fuel consumption by 15%, lower CO2 emissions and make it quieter than the engine’s predecessor, the CFM56, by using breakthrough materials and technologies. The LEAP engine has logged more than 10 million engine flight hours in less than five years of commercial service. “We are incredibly honored by IndiGo’s renewed trust in CFM,” said Gaël Méheust, president and CEO of CFM International. “We are fully committed to helping IndiGo optimize its operations by providing them with industry-leading asset utilization, fuel efficiency and overall cost of ownership.“

In 2019, IndiGo selected LEAP-1A engines and signed a long-term service agreement for engines to power 280 A320neo family aircraft. This new agreement, therefore, secures the LEAP-1A engine and its long-term service agreements for a total of 590 IndiGo A320neo family aircraft.

Riyaz Peermohamed, IndiGo’s chief aircraft acquisition and financing officer, said he was “pleased to extend our partnership with CFM” for the new addition to the airline’s fleet. “The introduction of the CFM LEAP engines in our fleet will allow us to maintain our strong focus on lowering operating costs and delivering fuel efficiency with high standards of reliability,” he said.

For example, the engine uses parts made from advanced, lighter-weight, more heat-resistant materials, including ceramic matrix composites (CMCs) that can handle temperatures approaching 2,400 degrees Fahrenheit, where even the most advanced alloys grow soft. In general, jet engines can operate more efficiently at higher temperatures. “I thought it would be the holy grail if we could get it inside machines, and get more power and savings out of our jet engines,” said Krishan Luthra, the GE researcher who spent several decades working on the material. “It could really make an impact.”

IndiGo currently operates seven A320neo and 15 A321neo planes with LEAP-1A engines. “India’s aviation sector is poised to grow from strength to strength, and we will continue on our mission of building a world-class transportation network,” IndiGo CEO Dutta said. “We are here to deliver on our promise of providing low fares and a courteous, hassle-free experience to all our customers.”

Image credit: IndiGo.

This article originally appeared on GE Reports.