Category: Our Work

Background

ACL commenced preparation for the London 2012 Olympics in 2009.

The initial phase included working with Atkins on behalf of the DfT to build a traffic forecast for the event for all traffic types (scheduled, charter and GA/BA) and to evaluate whether the forecast traffic could be accommodated within the existing South East England airport capacity.

Our forecast predicted that there would be 10,251 GA/BA movements, an additional 200 commercial scheduled and charter movements and 238 Head of State Movements. Based on the forecast 3 key areas emerged:

• The London airports had sufficient capacity for the handling of the aircraft and passenger forecasts.
• All airports within South East of England should be coordinated for the period of the Olympic Games
• Flight plans should only be approved if the operator held corresponding airport slots.

Next Steps

Using the reports as its basis, the DFT conducted an industry wide consultation regarding coordination across 40 airports in SE England. Post consultation it was deemed that airports should be fully coordinated and that ACL should be the Coordinator. In August 2011 legislation via a Statutory Instrument was enacted which instructed the Olympic airports that they would be coordinated for the Olympics period, and that ACL as the coordinator was entitled to charge for any costs incurred. Charges would be based on a simple ‘charge per movement’ formula.

As mentioned above, 10,251 GA/BA movements across 40 airports were forecast to operate during the Olympics. As a result of this forecast, parking was highlighted as being a constraint at some airports.

A number of the smaller airports parking aprons were not marked out with specific stands and parking capacity therefore varied depending on the size of aircraft requesting parking. In the light of this complexity and the volume of bookings anticipated ACL concluded that the only practical booking process was for the airport to take the original enquiry from the operator, check the parking constraints and then book the required slot in the Online Coordination System (OCS).

ACL regularly communicated to both operators and airports in order to:

• Summarise the volume of traffic forecast and the subsequent need for coordination
• Describe which flights would be subject to coordination (all IFR but not VFR).
• Outline how the coordination process would work.
• Describe the Olympics slot booking process.
• Highlight that penalties would be incurred if a flight plan was created that did not have a matching slot.

ACL staff attended a number of industry events (IATA conference, UK, and European business aviation meetings, CAA hosted events, NATS conferences, Eurocontrol (Air Navigation Provider)conferences and DFT events) to brief as many flight planners and operators as possible prior to the Olympics.

ACL also published bulletins and instructions describing the Olympics coordination process on industry websites and via industry publications such as NOTAM’s (Notice to Airmen) and AIP’s (Air Information for Pilots).

As part of the coordination process a Single Coordination Committee (SCC) was created chaired by the DfT and advised by ACL.  This met twice prior to the Olympics in order to agree the airports capacity declarations. The overall objective of the SCC was to ensure that the total airspace capacity over SE England was effectively managed, to ensure smooth operations for all operators.

The SCC’s capacity declarations were guided by advice from ACL, the CAA Safety Regulation Group and NATS.  In particular NATS used extensive simulation runs to provide guidance on how each airports capacity declaration would impact the efficient management of the airspace.

A number of system modifications were implemented to ensure robust and effective communications were maintained with operators, airports and industry bodies:

• A two year (minimum length available) license to use the DFS Stanly slots to flight plan matching system was purchased
• A dynamic update of ACL slot data into the DFS system for slots to flight plan matching was created
• A dynamic update of flight plans data from Eurocontrol (Air Navigation Provider)into the DFS system was also created
• A dynamic update of slot bookings data was supplied to Eurocontrol (Air Navigation Provider)by ACL.
• Modifications were made to ACL’s coordination software (SCORE) and to the OCS to support GA/BA bookings at four letter code ICAO airports
• A separate database and servers were created for Olympics bookings data to ensure data integrity was maintained at all times

The ACL Information Systems team implemented all of these changes in advance of the coordination period to ensure sufficient testing time was available. The overall performance of the ACL IT systems across the Olympics was 100% availability.

The majority of airports opened for bookings from 5 September 2011. In reality, the majority of the Olympics bookings were not made until 21 – 7 days prior to their date of operation.  This caused concerns at some airports as it proved hard to plan resources efficiently to meet demand.  ACL distributed latest bookings information on a regular basis during the build up to the Olympics to all airports and CAA, DfT, NATS and Eurocontrol. Below illustrates the bookings as we received them.

ACL thoroughly evaluated two slots to flight plan matching systems, one developed by Eurocontrol (Air Navigation Provider) and one by the German ATC provider DFS. Following this evaluation, the DFS Stanly system was selected as the preferred solution as it had following benefits:

It was available “off the shelf” as a proven system already in use within Europe

It had been used successfully during the 2006 World Cup in Germany.

It monitored both arrivals and departures.

Delivery – How we managed

ACL staff and airports operations staff were well briefed and able to handle the volume of slot requests effectively. The process of smaller airports checking parking capacity first, before making a booking on behalf of the operator in OCS, worked smoothly and there were no major issues.  OCS proved itself to be able to handle the extra volume of airports and bookings and there were no systems issues.

Total GA/BA bookings received over the period were 9,759, very close to the forecast of 10,251.

The movements were spread over the period in a similar pattern to that forecast, with peak demand days occurring around the opening ceremony, closing ceremony and 100m’s final.

Prior to the Olympics there was a great deal of focus on the expected high volume of HoS flights. In particular DfT were concerned there would not be sufficient parking in the South East to accommodate the expected volume of large aircraft. Heathrow airport had agreed with the DfT that it would not accept any HoS flights and Gatwick airport had restricted the parking capacity available for all ad hoc operations.

Prior to the Olympics, ACL worked closely with the airports, DfT and FCO to agree a robust and effective communications process for coordinating all HoS flights. ACL agreed individual constraints and approval processes with each major airports. Also, as mentioned previously, a dedicated HoS person was appointed for each day shift to provide DfT and FCO with a single point of contact, and to coordinate the flights across the Olympics airports.

The processes developed jointly with the airports, FCO and DfT worked well.

The DFS system was used intensively to ensure that operators obtained slots to match their flight plans. The DFS system generated 2,099 warnings of potential no slot or significantly off slot operations and ACL sent 835 warning messages.

The difference between DFS warnings generated and the actual number sent was driven by:

• DFS generating a warning message which on investigation did not require action (e.g. DFS highlighted bmi coded flight plans as not having a matching slot as the slot was held under a BA code)
• ACL staff proactively calling operators to alert them that an issue needed to be addressed, which resulted in less written warnings.

Of the 835 warning messages sent, 53% were for significantly off slot operations and 47% for operations without a slot. As can be seen from the table below, the majority of warning messages were generated at airports with a high number of GA/BA operations including Luton, Stansted and Farnborough.

Number of DFS warning messages sent by airport

Most operators responded quickly to the warnings and corrected the problem highlighted. However 353 flight plan suspension requests were made to Eurocontrol (Air Navigation Provider) (approximately 13 suspensions per day). Eurocontrol (Air Navigation Provider) was able to confirm back to ACL that a flight plan had been suspended within five minutes of receiving the request. Of those suspensions requested the majority were reinstated after the operator corrected the problem, with only eight operations not resolved before the flight operated.

The DFS system was in use on a 24hr basis, although experience soon showed that between 1800 and 0100 local time there were very few warnings to be processed. However, the number of warning never quite dropped to zero.  

Feedback Received

The following feedback has been received from the Olympics airports:

Thanks for all the help over this period (and the build-up to it!) Particularly those in the ACL call centre, who have always been helpful and able to answer all of our weird and wonderful questions.

Best regards Everyone from Biggin Hill Flight Operations

Not having used the ACL system before I did have a few problems.  A quick telephone call to your office and all of your staff were more than helpful and were always pleased to assist.

Thank you very much. Best regards  Jo Bampton Operations Cranfield Handling

Gatwick did not turn out to be so busy for the Olympics, but I think this was in part due to the 10 day slot ruling.  I worked very closely with both Robert and Fernando in the build up to the Olympics to ensure that GA did not break out of the allocated parking area that GAL had put into place.

I would like to thank both Robert and Fernando for all their help and assistance in the build up to and during the Olympics.  They made the whole event more manageable.

Kind regards, Jonna Mercercox Station Manager LGW  Signature Flight Support

We were pleased with the way things went even though it was not as busy as we expected. With regard to using OCS on a more permanent basis, we did look at it several years ago. The unscheduled nature of our business does not necessarily lend itself well to the system unless we had definitive number of restrictions per hour, which is something we do not yet require. However, as our business grows, this may be a way that we move towards. Certainly, we now have a better understanding of how OCS works and what benefits it could bring us, so will keep you in mind for a future strategy.

Roger Walker, Director Airport Operations, TAG Farnborough

Goodwood had limited movements through slot allocation but there were no issues with those that we handled.   Traffic throughput for people arriving for the actual Olympics was far lower than anticipated; instead our movement growth was from aircraft relocating to Goodwood from the ‘airspace constrained’ London catchment aerodromes. In terms of feedback about the ACL staff / processes, I think it worth mentioning my appreciation for members of your team who had time and patience in explaining the slot allocation process to some of the staff at Goodwood, many of whom had never worked in a slot controlled environment.

Kind regards,
Mark Gibb
Aviation Operations Manager
Goodwood Aerodrome

Issue

London Heathrow has a desire to ensure every last ATM is utilised however only wishes to add more flights if it does not impact on performance at the airport. Resilience is driving many operational changes to ensure that delays and passenger experience is not compromised. One method of improving resilience is the spreading of flights across the day.

ACL Concept

ACL has the expertise and the data to analyse an airport schedule and suggest constraints on the runway, the terminal, parking and gates to help the airport and the airlines deliver a service to the planned schedule.

ACL recently provided analysis on the London Heathrow Airport schedule to evaluate the impact of introducing a 5 minute scheduling constraint to improve the spread of flights across each hour of the day. This included determining the probable number of moves by arrival and departure to achieve a five minute runway constraint which could then be used to determine the likely reduction in delay. Previously Heathrow had been coordinated with a runway ten minute offset constraint for over 20 years.

ACL was the innovator of this project, we were able to incorporate other stakeholder contributions to deliver a feasible schedule that utilised the five minute rnway constraint.

Part of the delivery involved demonstrating feasibility and forecasting probable outcomes.  ACL also worked with the airport and NATS to demonstrate a reduced delay profile with the benefit of improved on time performance.

The work involved re-coordinating the historic baseline to the agreed new five minute constraint in advance of the SHL, this allowed airlines to accept or reject requested voluntary moves.

The final work involved Coordinating to the new constraint in summer 2016 and winter 2016/17.

Benefits

The new constraint produced an operationally deliverable schedule having removed infeasible periods of eight movements on arrival and eight departure movements in any given five minutes period.

The change has the potentially to reduce delays and stack holding with the added benefit of on time performance improvement for the airport infrastructure and the airlines schedules.

Process

All requested historic time moves by ACL within the five minute schedule were voluntary moves, Airlines had the right to refuse to move off their historic slot time due to their own commercial and connection requirements. The voluntary situation acknowledged that not all five minute overages would be eliminated in the first season using the new constraint. ACL worked closely with airlines to encourage acceptance of the suggested moves to ensure maximum impact.

Outcome

ACL eliminated eight movements in five minutes in one season, with the majority of five minute periods below the five movement level. There are a few minor periods of five minutes where six movements are scheduled. It is expected that over the next three equivalent seasons the overages will be reduced to the five movement per five minutes declared capacity.

The initiative will enable NATS/ Airport operations/ Airline operations/handling agents to have improved ability to deliver to the schedule plan.

Background

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

Process

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.

Benefits

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

Value

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.

Outcome

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.

Case Study – London Gatwick Capacity Utilisation

The airport operator of London Gatwick the world’s busiest single runway had an initiative to drive utilisation of its infrastructure with an aim of increasing runway movements to 55 per hour at peak hours and overall daily movements. Gatwick has traditionally been a leisure dominated airport with seasonality causing fragmentation of the schedule resulting in poor utilisation across the season. For example a summer peak flight for 6 weeks preventing a full season operation as the fragments prevent valuable full season flying from obtaining a common seasonal time. In recent seasons the demand profile of the airport has changed with increased demand for new scheduled year round operations. Once fragmentation occurs generally there will be season upon season of fragmented growth thus making it harder to line up schedules and creating an unappealing environment for scheduled traffic to operate.

ACL embarked on a campaign to reduce the impact of fragmentation by utilising it’s existing relationships with the LGW base carrier community to highlight this problem and the effect that it has had on not only their own growth plans but those of future new entrants which provide a range of potential connections.

Historic fragments cannot be removed as grandfather rights need to be respected. By demonstrating new and different ways to schedule flights that integrate into an airlines wider network, ACL has been able to significantly reduce the volume of short season flying held. ACL have turned 7 week historic fragments into 22 weeks with these lines of flying being operated.

The above initiative has resulted in a maximum runway delivery of 58 movements in a given hour from a declared capacity of 55 movements and saw the busiest day movements increase from 904 in S14 to 948 in S16 an increase of 4.8%.

This success has been achieved through ACLs proactivity working with airlines to achieve voluntary moves.

The growth success can be seen in the following chart: