Our Work



London Luton experienced continual growth over a number of seasons, culminating in a significant breach of the declared terminal departure limit on particular days throughout the Winter 2011/12 season. Under the Level 2 process, ACL requested carriers to make voluntary moves to smooth the peaks across the affected period.  This process could not be enforced and resulted in carriers refusing to move.  The peak continued to grow, increasing security delays on departures and the airport began to explore the possibility of changing the status of the airport from Level 2 to 3. Fig 1 is an indication of the overages caused by airlines refusing to accept voluntary adjustments in Winter 2011/12

Fig 1: Terminal departure throughput by day of week 0630-0845 (GMT) Winter 2011/12



The airport commissioned an independent capacity review whilst ACL advised on the process and timelines behind moving an airport from Level 2 to Level 3, highlighting the deadlines required to meet the Worldwide Scheduling Guideline date for declaring the change.   ACL analysed the data which demonstrated growth over the seasons along with the number of refused moves which were impacting the declared capacity.   The airport and ACL jointly held individual meetings with the carriers and general aviation handling agents to explain the issues and the reason for the request to change the status from Level 2 to 3.

The capacity review identified parking and taxiways leading to the runway along with departing passenger throughput in the terminal as areas for concern going forward, all contributing to delays in the morning peak operation.  ACL were already modelling parking in the score system to ensure schedule feasibility against the number of available stands but again if this parameter were to be breached ACL could only request and not enforce a schedule adjustment under Level 2.

The UK Department for Transport (DfT) were engaged and ACL contributed an independent voice to the debate on the background to the change of status request by the airport.  ACL remained in close contact with the DfT to ensure any questions were answered impartially.

The DfT put this information out for consultation and carriers were invited to respond with their views.  Fourteen entities responded with one against the change in status. The Secretary of State concluded the shortfall of capacity was of such a serious nature that significant delays could not be avoided at the airport and there were no possibilities of resolving these problems in the short term.

London Luton Airport was formally declared as Level 3 effective Summer 2013.


Level 3 status allowed ACL to enforce slot adjustments and apply a higher level of control over the schedule from Summer 13 onwards.  This resulted in the schedule being smoothed out across the 0630-0845 time period instead of the bunching previously experienced.

Fig 2: Terminal departure throughput by day of week 0630-0845 (GMT) Winter 2016/17

Terminal departure throughput


ACL will work with airport customers to impartially gather the data to present to interested parties. With detailed regulatory knowledge of both the EU Slot Regulation and the Worldwide Scheduling Guidelines, ACL is able to offer guidance on the process behind a change in airport status.  With close interaction between ACL and all stakeholders the message is conveyed to ensure all parties understand the implications and reasons for the change.


The role of ACL is to maximise capacity at airports.  Where demand exceeds capacity, further controls are required to smooth the schedule and remove sharp peaks which may impact the airports ability to deliver a punctual schedule.  Level 3 allows for the control of slot allocation along with the monitoring of slot usage to ensure carriers adhere to the cleared slot.

ACL will also offer advice to airlines and the relevant authorities on all matters likely to improve airport capacity or slot allocation flexibility, in particular on any area which will help the airport return to Level 2 or Level 1.

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