A model of the latencies associated with the downlink of ACAS RA information to ATC centres has been specified and implemented as a software application. The model has been used to investigate the performance of two candidate downlink methods (Mode S RA Report, and 1090 MHz extended squitter) in a set of scenarios representative of those that can be expected in European airspace. The preliminary results presented here show that RA downlink can greatly increase the timeliness of information for improved situational awareness in all contexts, and in safety critical situations will be in time to allow prevention of unwanted controller involvement in RA encounters.