Heathrow publishes its report on Phase 2 of its Operational Freedoms Trial
The Heathrow Operational Freedoms Trials will end on 28 th February, a month earlier than planned, as enough data has been gathered. The first report on the trials was produced in April 2012. Now the second report has been published, for the period July to October 2012. It is a complicated and technical document, that is not particularly accessible to the non-expert! However, in its conclusions it says that during the trial there were (on westerly operations) about 22 extra flights on the other runway, which would not normally happen, taking the number from an average of 15 to 37 per day, as this could be done if there was a 10 minute delay trigger. They also say there was a very tiny reduction in stacking time and thus fuel burned, though this may also be due to other factors. They also say the number of complaints was significantly up, that about 80% of the enquiries were accounted for by 10% of the callers, and about 60% of the callers made contact only once.
Details of the trails, from the Heathrow Airport website at Operational Freedoms Trial
Heathrow Operational Freedoms Trial – Phase 2
End-of-season report, summer 2012
This document is Heathrow’s report on the “End-of-Summer Season” of Phase 2 of the Operational Freedoms trial at London Heathrow Airport. The report covers the period from 1 July 2012 to 27 October 2012.
The phased trial to provide an evidential basis for the consideration of new operating procedures at Heathrow to reduce delay, improve punctuality and increase resilience whilst maintaining a balance with impacts on local communities was approved by and, on 14th July 2011 announced by the Minister of State for Aviation (Theresa Villiers).
The Operational Freedoms trials, undertaken collaboratively by Heathrow and NATS, are based on the premise that a segregated mode of runway operation is unable to withstand or recover from typical fluctuations in air traffic demand caused by weather, schedule perturbations and network effects.
Typical Heathrow scenarios, identified as root causes of disruption were tested. Trial requirements included a more flexible approach to the operation of different runway modes while subject to appropriate governance, performance management and constraint..
Phase 2 of the trial tested three sets of Operational Freedoms. The first two are termed reactive measures, in that they are activated in response to a trigger condition being met. These are:
– operating arrivals on the designated departures runway, or TEAM* (Tactically Enhanced Arrivals Mode) after 07:00 hours local time.
This freedom was applied from 1 July 2012 to 31 December 2012. It can be triggered by one or more of: an actual or predicted inbound delay in the stacks of 10 minutes or more; headwinds at 3000 feet of 20 knots or more; anticipation that the schedule will run later than 30 minutes or 30% of flights are running outside of the 15 minutes punctuality target; and the need to recover from disruption
– early vectoring of departing aircraft from set departure routes (Standard Instrument Departure routes and the Noise Preferential Routes (NPRs) that bound them), with the same triggers as above, in segregated mode.
This freedom was applied from 1 July 2012 to 31 January 2013. Note that the freedom to allow early vectoring in dual departures mode was not tested during the Trial (see www.heathrowairport.com/noise/noise-in-your-area/operational-freedoms-trial/phase-2 for further information).
In the preamble to this phase of Operational Freedoms, it was proposed that an additional freedom should be tested whereby a small number of early morning arrivals would be artificially delayed until after 0500 hours local time. This would have provided up to an additional 30 minutes of respite in return for a busier period until 0600 hours. It was latterly decided that this freedom would not be explored in this format for complex scheduling reasons.
In addition to the reactive measures, there are three types of proactive test concerning arrivals each of one month in length:
– moving A380 landing aircraft out of the arrival stream to land on the departures runway and/or moving the aircraft in front of or behind the A380 out of the arrival stream to land on the departures runway
– moving light/small wake vortex category aircraft out of the arrival stream and landing them on the departure runway.
– landing Terminal 4 (T4) traffic on the southern runway when the designated landing runway is the northern runway.
For arrivals the results of the statistical analysis indicate that:
– the trial appears to have increased de-alternation on westerly operations to approximately 22 additional de-alternated flights, post-07:00, per day, an increase from an average of 15 per day to an average of 37 per day. It is likely that this increase is due to the freedom to apply TEAM at a 10 minute delay trigger as opposed to the 20 minute delay trigger as in the past
– application of both reactive and proactive TEAM is associated with a statistically significant increase in runway arrival rate; evidence also suggests an association of both with a reduction in Heathrow attributed ATFM delays
– comparison of stackholding over the trial period with the previous three years shows both a significant reduction of approximately 0.6 minutes per flight (although this does not account for other influencing factors) and, evidence for an association between both reactive and proactive TEAM and a reduction in stackholding. The latter might be between 0.32 to 0.45 minutes per flight in stackholding delays: further analysis is required for confirmation
– there is evidence for an association between the application of:
– – reactive TEAM and improvement in arrival punctuality
– – arrivals freedoms, both reactive and proactive, and reduced taxi-in time both overall and specifically T4 arrivals. Specific proactive T4 arrivals test indicated careful selection by ATC controllers when applying reactive TEAM.
For departures, the results of the statistical analysis indicate:
– the application of Operational Freedoms vectors appears to be associated with an increase in hourly runway departure rate of approximately 0.2 per vector. This is countered by evidence for an association of the application of Operational Freedoms TEAM with a reduction in runway departure rate of approximately 0.5 per landing on the departure runway
– evidence to suggest the association between the application of Operational Freedoms vectors and reduction in start-up delay and a negative association between the application of OF TEAM and an increase in start-up delay; both associations require further investigation to be understood fully
– there is no statistically significant association between the application of Operational Freedoms vectors and holding point delay; no significant relationship between Operational Freedoms and taxi-out time; and, no significant difference between departure cancellation rates during the trial and previous periods
– the situation regarding departure punctuality appears to be very complex. To date, it has not been possible to de-convolute the many interactions between separate elements of the departure process and it is not possible to draw any firm conclusions regarding departure punctuality at this stage.
The impact of proactive tests has been investigated separately to the reactive freedoms through the regression analysis with the following conclusions:
– there is evidence to suggest that proactive tests are associated with a reduction in stackholding, irrespective of the type of model that is applied in the analysis, indicating the positive effect of applying the freedom to the arrival stream around A380 arrivals
– there is also some evidence to suggest that the proactive tests are associated with a reduction in both overall taxi-in times but more significantly with a reduction in T4 taxi-in times, indicating the effectiveness of applying the freedom to T4 arrivals.
The measurement of economic effects of the Operational Freedoms has been limited to situations where there is a statistically-demonstrable link between change in a KPI and the use of Operational Freedoms which has resulted in an estimated positive economic benefit in reductions to direct airline costs and fuel costs incurred by airlines at Heathrow of approximately £3.5 million for a summer season, approximately a seven month period. This comprises a net benefit of £4.3 million for arrivals and net cost of £0.8 million for departures.
Looking at the Operational Freedoms individually, it is estimated that the following benefits apply for a summer season:
– reactive arrivals measures (TEAM*): An estimated net benefit of £2.1 million, noting that this comprises a benefit of £3.6 million for arrivals and a cost of £1.5 million for departures
– early departure vectors (OF vectors): An estimated net benefit of £1.0 million
– proactive arrivals measures: An estimated net benefit of £0.4 million, noting that this comprises a benefit of £0.7 million for arrivals and a cost of £0.3 million for departures.
This end of season report for the period July 1st to October 27th 2012 covers approximately four months of the nine month Phase 2 trial period. At the end of Phase 2, all of the data gathered throughout the whole of this phase together with that from the first Phase will be aggregated into a trial report for the Operational Freedoms strategic framework originally proposed by the South East Airports Taskforce.
Full report, (127 pages) at
The first report was in April 2012
Heathrow Operational Freedoms Trial
Phase 1 Report
Operational Freedoms trial
Government announcement re early completion to Operational Freedoms trial at Heathrow