Qatar Airways has dropped Pratt & Whitney from its order for Airbus A320neo-family jets, switching instead to the rival CFM International Leap-1A.
The Middle Eastern carrier had originally been scheduled as the launch operator for the A320neo family, having ordered 50.
But it became engulfed in a row over the reliability of the Pratt & Whitney PW1100G engine, and the launch operator position was ultimately taken by Lufthansa.
Qatar started cancelling individual A320neo deliveries as the engine dispute persisted.
It subsequently threatened to swap powerplants to CFM and, two years ago, scrapped the entire A320neo order in favour of a revised deal for 50 of the larger A321neo.
The Doha-based airline has confirmed that it is switching the engine selection, choosing the Leap-1A for all 50 jets in a deal it values at $4 billion including service contracts.
Qatar's fleet of conventional A320s comprises 38 aircraft but only eight are fitted with CFM56 engines.
It says the first A321neos will arrive in 2020, later than the original delivery date of 2019 given in the original order disclosure.
Chief executive Akbar Al Baker says the Leap engine has "proven efficiency" in operation.
"This engine addresses our strategy to operate a state-of-the-art fleet with the most advanced technologies in the industry," he adds.
Qatar Airways is taking the 'Cabin Flex' version of the A321neo, with its reconfigured door arrangement.
In the aftermath of the PW1100G dispute the airline also negotiated an agreement to take Boeing 737 Max jets, which are exclusively powered by the Leap-1B.