The deliveries of a new batch of A380-800s for Emirates are likely to be delayed beyond 2020 as Airbus and Rolls-Royce failed to agree on the specifications of a new engine variant for the units by the scheduled deadline, Bloomberg has reported.

The powerplants delivered by the manufacturer reportedly failed to meet the performance requirements, particularly in regard to price and fuel burn.

In the worst-case scenario, the lack of an agreement between the aircraft manufacturer and Rolls-Royce might even threaten the fulfilment of the deliveries for the Dubai International-based carrier.

Emirates ordered twenty firm A380-800s with a further twenty options in January 2018, effectively throwing a lifeline to the manufacturer which struggled to win orders from other airlines. The carrier is by far the largest user of the type and already operates 105 double-deckers, out of 220 active globally. Including the twenty new jets ordered earlier this year, Emirates still has fifty-eight A380s on order.

According to the ch-aviation fleets module, the first ninety A380s delivered to Emirates were equipped with Engine Alliance GP 7270 engines, while the subsequent fifteen quadjets are propelled by Rolls-Royce Trent 900 units. All the remaining A380s on order are also to be equipped with Rolls-Royce engines.

Engine Alliance, a joint venture between General Electric and Pratt & Whitney, said it could deliver its current generation engines for the future A380s. However, Bloomberg reported that the JV's approach to the quadjet programme is lukewarm at best, as it focusses much more on engines for other types.