India’s largest passenger airline IndiGo has ordered more than $20bn of LEAP-1A engines from CFM International, a joint venture of GE Aviation and Safran Aircraft Engines.

The contract includes spare engines and an overhaul support agreement and is reportedly the largest ever single engine order in history.

IndiGo also signed a long-term service agreement to support its new LEAP-1A fleet.

The engines will power IndiGo’s fleet of 280 Airbus A320neo and A321neo aircraft. Delivery of the first LEAP-1A-powered A320neo is scheduled in 2020.

The LEAP engine has recorded approximately five million engine flight hours in less than three years of commercial service.

IndiGo chief aircraft acquisition and financing officer Riyaz Peermohamed said: “The CFM LEAP engine will allow IndiGo to maintain its strong focus on lowering operating costs and delivering fuel efficiency with high standards of reliability. This new partnership will allow IndiGo to continue to provide affordable fares to its customers.”

IndiGo has been a CFM customer since 2016. The airline currently operates a fleet of 17 A320ceo aircraft powered by CFM56-5B engines.

With its fleet of more than 230 aircraft, IndiGo offers 1,400 daily flights, 54 domestic destinations and 19 international destinations.

CFM International president and CEO of Gaël Méheust said: “Since the LEAP entered into service in 2016, it has consistently delivered on every promise we made to our customers when we launched the programme in 2008.

“We are fully committed to helping IndiGo optimise its operations by providing them with the industry-leading asset utilisation, fuel efficiency, and overall cost of ownership.”

In total, CFM International has more than 500 CFM56 engines and 60 LEAP engines currently in operation in India.

Apart from IndiGo, Peach Aviation has also signed an agreement with CFM International for the purchase of 20 LEAP-1A engines to power the airline’s new fleet of Airbus A320neo family aircraft.

The agreement is valued at $294m at list prices and the aircraft were ordered in 2016.