IAA Website - Saturday, February 4, 2023 3:05 AM

Reduced Departure Intervals

On 5th March 2014, in response to increasing traffic levels, and in order to increase the efficiency of Dublin departure operations on runways 10 and 28, whilst maintaining existing safety standards, the IAA introduced a six-month operational trial to reduce the interval between successive departing aircraft of the same category. Previously, the following aircraft was given take-off clearance when the preceding aircraft reached 1.5NM from the departure end of the runway. For the trial, this interval has been reduced to 1NM.

The reduced departure operational trials were successfully completed at the end of 2014 and the procedures for reduced departure intervals are now fully operational. Recent analysis of departure data has shown a reduction in the departure interval of up to 15 seconds. The all-important safety targets have been met during these trials. The minimum airborne separation standard is for 3NM to be applied between these aircraft and the trials have shown that the average separation achieved to date is 4.1NM (with the minimum being 3.5NM).

Further enhancements to the reduced interval procedures are planned for 2017, which will reduce the departure interval and increase the departure capacity further. This coupled with HIRO operations will increase the efficiency of the main runway at Dublin.

High Intensity Runway Operations (HIRO)

HIROs are used to optimise separation of aircraft on final approach in order to minimise runway occupancy time (ROT) for both arriving and departing aircraft and to increase runway capacity. Expeditious exit from the landing runway allows air traffic control (ATC) to separate aircraft with the appropriate radar separation minimum during final approach.

Arrival spacing will be adjusted in accordance with demand to make most efficient use of the runway and to reduce departure delays. ATC will consider every aircraft at the holding point as able to commence line up and take-off roll immediately after clearance issued.

HIRO will provide environmental savings to the airspace users in form of reduced fuel burn and CO2 emissions, and reduced ground noise. This is based on reduced airborne arrivals times and delays, and reduced taxi times as runway throughput increases.