The first day of trials of the Reduced Longitudinal Separation Minimum in the North Atlantic (RLongSM) project took place on 5 April. The project, which is part of the AIRE programme, aims to analyse the impact of the introduction of a new five-minute longitudinal separation standard, focussing on: flight safety, fuel burn, environmental impact, ATC workload and FANS economic benefit. Flight trial data was successfully captured in the Gander and Shanwick Oceanic Control Areas, where the software that enables reduced separation was successfully implemented at the end of March. The next trial will take place on 10 May.