EUROCONTROL Data Snapshot on summer delays

In a recent snapshot , we showed how checking COVID documents was a significant cause of delays to passengers, up to 0.7 minutes per flight in July 2021. Now looking back over the summer months, despite en-route ATFM regulations being lower than 2019, we see that delays in total have been climbing again. Summers 2018 and 2019 were very poor for delay, with 18 and 16 minutes of delay per flight on average. Summer 2021 is lower than that but, at 10.9 minutes per flight, already close to the 2010-2017 average (12 minutes).

Airlines categorise their delays into primary causes and reactionary delays, the latter caused by delays on earlier flights (of this aircraft, for this crew, or these passengers). The most common primary delays are from airlines' own processes, such as baggage loading, boarding or refuelling. Airport processes (such as check-in), air traffic management and government (such as health checks) make up the remainder. While reactionary delay in theory is due to some original, primary cause, in practice the situation is too complex to be worth splitting 'reactionary' amongst the primary causes.

As passengers, most of us have experienced reactionary delays: arriving at the boarding gate to find the aircraft hasn't yet arrived. It's a problem carried from flights early in the day to those later on. Airlines try to break the chain of delays by building gaps into the schedule, or switching aircraft, or accelerating processes such as boarding to make up lost time. With relatively light traffic this summer, they were able to do more of that, which is why the rate was relatively low (36% of total, rather than 45%).

These solutions rely on luck (can we get everyone boarded quickly?) or are costly in capacity (having spare aircraft). Better to aim to stop the delays at source. That's why the EUROCONTROL Network Manager and all the operational teams at airlines, airports and air navigation service providers work to reduce (primary) delays in the ‘first rotation', the first couple of flights each day. 10 minutes of primary delay during the first rotation can cause 40 or 50 minutes in total across the day.

Total delay remains relatively low (19 million minutes) compared to 2018-2019 (45-50 million). But, as the recovery continues, keeping down delays on the first flights of the day needs to be a priority.