An aircraft landing event system comprising a processor communicatively coupled with memory storing previous aircraft landing event data, the processor configured to: receive environment information representative of an environmental condition of a runway approached by an aircraft ; receive, from a landing system of the aircraft, retardation information representative of a retardation demand of the aircraft during an anticipated landing event of the aircraft on the runway, wherein the retardation demand is determined by the landing system of the aircraft; select aircraft landing event data from the memory on the basis of the environment information and the retardation information; determine a performance indicator for the landing event on the basis of the aircraft landing event data selected by the processor; and communicate the performance indicator to the landing system of the aircraft; wherein the processor is configured to determine a relationship between performance indicators and both environment conditions and retardation demands of the aircraft landing event data selected by the processor, and wherein the processor is configured to determine the performance indicator for the anticipated landing event on the basis of the relationship. communicatively coupled with memory storing previous aircraft landing event data, the processor configured to: receive environment information representative of an environmental condition of a runway approached by an aircraft ; receive, from a landing system of the aircraft, retardation information representative of a retardation demand of the aircraft during an anticipated landing event of the aircraft on the runway, wherein the retardation demand is determined by the landing system of the aircraft; select aircraft landing event data from the memory on the basis of the environment information and the retardation information; determine a performance indicator for the landing event on the basis of the aircraft landing event data selected by the processor; and communicate the performance indicator to the landing system of the aircraft; wherein the processor is configured to determine a relationship between performance indicators and both environment conditions and retardation demands of the aircraft landing event data selected by the processor, and wherein the processor is configured to determine the performance indicator for the anticipated landing event on the basis of the relationship. receive environment information representative of an environmental condition of a runway approached by an aircraft ; receive, from a landing system of the aircraft, retardation information representative of a retardation demand of the aircraft during an anticipated landing event of the aircraft on the runway, wherein the retardation demand is determined by the landing system of the aircraft; select aircraft landing event data from the memory on the basis of the environment information and the retardation information; determine a performance indicator for the landing event on the basis of the aircraft landing event data selected by the processor; and communicate the performance indicator to the landing system of the aircraft; wherein the processor is configured to determine a relationship between performance indicators and both environment conditions and retardation demands of the aircraft landing event data selected by the processor, and wherein the processor is configured to determine the performance indicator for the anticipated landing event on the basis of the relationship. <EOS>