A $16bn order from Dubai carrier Emirates that was described as saving the Airbus A380 programme has reached a deadlock over the engines, according to reports.
Emirates, which is by far the largest operator of the A380, firmed up the order for 20 aircraft and 16 options in February after months of talks.
Bloomberg cited sources as saying the deal is now being held up by negotiations between Emirates and Rolls-Royce on the price and fuel burn of the engines.
The companies have already missed a deadline to select engines, which could delay the first delivery of planes from the order in 2020 or even see it scrapped entirely, according to the sources.
Emirates operates more than half of the A380 order book and the February order brought its commitment to 178 worth more than $60bn.
It switched to Rolls-Royce engines for the craft a few years ago having previously used a joint venture of General Electric and Pratt and Whitney named the Engine Alliance.
The latter has not received an order for years and is understood to not be aggressively pursuing a rival bid to Rolls-Royce, according to reports.
An Engine alliance spokesperson said the venture had offered to provide Emirates with GP7200 engines.
“We look forward to an Emirates announcement, and we are also focused on supporting their fleet for decades to come.”
Rolls-Royce has been unable to meet fuel burn guarantees since winning a $9.2bn deal to power 50 aircraft in 2015.
Should the Emirates deal fall through, the future of the A380 programme will once again be questioned.
Airbus is cutting production from 15 craft a year in 2017 to six from this year due to limited demand.
Emirates president Tim Clark had previously indicated the carrier would commit to purchasing options from the February order “sooner rather than later”.