The European aviation authority EASA has published an urgent airworthiness directive pointing out a specific issue with the CFM LEAP-1A engines installed in newer Airbus A321neo models. These engines, known for their high efficiency and environmental friendliness, are showing signs of premature coking of the injectors. This issue, which currently appears to be limited to aircraft of a specific operator, could have far-reaching implications for the operation of the affected aircraft. The EASA airworthiness directive, which will come into force on September 20, 2024, mainly affects seven Airbus A321neo aircraft delivered to Saudi Arabian Airlines between April and December 2023. In addition, the directive covers three other A321neo aircraft scheduled to be delivered to the same airline in the near future. EASA advises that the injectors of the CFM LEAP-1A engines in these aircraft may experience premature coking, potentially affecting the performance and safety of the engines. Coking, where residues from the fuel build up on the nozzles, can lead to serious technical problems. This can trigger the activation of a relief valve and affect the thrust control of the engines, which is critical for the safety and efficiency of the aircraft. Background of the problem and current investigations The problem of premature coking in the injectors was first identified on the Airbus A321neo models mentioned. EASA has not yet published any detailed root cause investigations, but premature coking of the nozzles is a concern as it can not only affect engine performance, but also potentially lead to unforeseen maintenance and operating costs. The airworthiness directive requires the airlines concerned to: