Everyone hates it when their flight is delayed. It’s also a major headache for airlines in terms of missed connections, disrupted fleet and crew schedules, night-time curfews, fuel, maintenance slots and aircraft repositioning. All those things generate extra costs for airlines which in turn put pressure on ticket prices. Delays also can damage an airline’s brand and possibly its overall long-term sustainability.

Being able to have more control over selecting which delayed flights to prioritise based on business needs is a big advantage for airlines and other actors, which is where the user driven prioritisation process, or UDPP for short, comes in.

Part of the SESAR PJ07 project, UDPP is a solution that help airlines prioritise their delayed flights. Under development since 2012, some UDPP features have already been deployed such as Enhanced Slot Swapping, while others have achieved different maturity levels. Two core UDPP functionalities, Fleet Delay Reordering and Selective Flight Protection, were validated earlier in 2019; the latest feature to be successfully simulated is ‘the Margins’. This feature allows airlines to interact with the Network through the provision of an additional set of information in order to mitigate the impact of delay and further improve their decision-making processes.

When a flight is delayed, it will have a time whereby the missed passenger connections, operational impact and associated costs increase significantly. The margins feature enables airlines to input this time across all their flights caught in a heavy delay and, in addition to estimated departure time which is already submitted to Network, create a 'margin of manoeuvre'. This in turn can be used to reorder and prioritise flights to best suit the needs of each airline when foreseen capacity reductions have been identified.

The Margins were successfully tested in a recent validation exercise at the EUROCONTROL Experimental Centre by operational experts from airlines (Air France, Air Baltic, Lufthansa Group/Swiss, HOP!, Transavia and El Al)  and IATA.

The exercise revealed that by offering airlines an additional set of information, they could optimise the position for a set of delayed flights within their margins, reducing the number of missed passenger connections, and lowering the cost of delay by 40% in a capacity-constrained situation.

Key features of UDPP

When there is excessive traffic in a sector or at an airport (a so-called hotspot), the Air Traffic Flow and Capacity Management (ATFCM) function can delay certain flights before they depart in order to keep operations safe. UDPP allows all actors in the decision-making process (airlines, airports, ANSPs and the Network Manager) to have a say in how delays are distributed across flights, not just taking a “first-planned, first-served” method of distributing them, which may not suit the airlines concerned as the cost of delay per flight can vary enormously between flights. UDPP gives airlines more flexibility to airlines to redistribute delays across their fleet by prioritising highly critical flights (especially ones that will have the greatest impact on the airline’s all-day schedule) over flights with a relatively low cost of delay. UDPP is particularly important for airlines that have several fights in a hotspot, which usually happens at airports where airlines have many fights scheduled in short periods. It allows airspace users more time to plan and act, and can reorder the whole affected fleet at once.

Prioritisation using UDPP allows airlines to reduce the overall number of missed passenger connections as well as the cost of delay. In addition, by involving multiple ATM actors, it aims to ensure that the actions of one airspace user to reduce its problems do not negatively impact other airspace users, with the overall aim of taking a network-centric approach to minimising delays and improving adherence to airport slots.

What’s next

The results of the latest exercise are being analysed in detail, with more insights available later this year. As part of the SESAR research programme, the next steps will be, starting in 2020, to validate UDPP together with several ATM processes for arrivals at a number of airports in Europe until the UDPP solution has been judged mature and ready to be implemented into operations.