The metrics used to measure our Fly quiet and green programme are, naturally, very complicated so these explainers should help you to get a better overall understanding of what the terminology means, what we measure, what data is supplied from manufacturers and Aviation Authorities – and how we combine all the data into the scores you see under ‘The league table’.
How are airline ranking positions calculated?
How is the overall score calculated?
Why are there different weightings for different metrics?
|Strategic noise metrics||Chapter number (noise certification)||50%|
|Strategic emissions metrics||CAEP standard (engine emissions certification)*||50%|
|Operational metrics||Continuous Descent Approach (CDA) violations||150%|
|“Late or early movement”||60%|
Operational metrics revolve around how the aircraft are flown; it is also an area the airlines have generally more control over in terms of daily operations than the strategic metrics which depend largely on long-term fleet planning. The higher weightings associated with the operational metrics therefore reflect the airlines’ ability to change their behaviour and improve their performance in the shorter term.
The lower weighting for the “late or early movement” is present to reduce the penalty for those airlines that are scheduled to operate their flights nearer to the Night Quota Period start time of 23:30, which in turn presents higher likelihood of incurring a violation in this metric.
*CAEP stands for Committee on Aviation Environmental Protection. More information available here.
What does the colour of the dot and the number inside the dot represent?
|Strategic noise metrics||Chapter number||50%||Green: Less than 2 (on average quieter than Ch14H)
Amber: 2 to 4 (on average noisier than Ch14H but quieter than Ch4H)
Red: more than 4 (on average Ch4H and noisier)
|QC/seat/mvt||50%||Green: best 75% of airlines
Red: worst 10% of airlines
Amber: remaining airlines
|Strategic emissions metrics||CAEP |
|50%||Green: Less than 2 (on average CAEP 6 or CAEP 8)
Amber: 2 to 8 (on average CAEP 2 and CAEP 4)
Red: more than 8 (on average pre-CAEP/CAEP original)
|NOx/seat/mvt||50%||Green: best 75% of airlines
Red: worst 10% of airlines
Amber: remaining airlines
|Operational metrics||CDA||150%||+5 percentage point increase over FQ thresholds:
Red: less than 60% compliance
Amber: 60% to 80% compliance
Green: more than 80% compliance
|Track keeping||150%||+5 percentage point increase over FQ thresholds:
Red: less than 90% compliance
Amber: 90% to 95% compliance
Green: more than 95% compliance
|“Late or early movement”||60%||Airlines will be compared against their own performance during the same quarter of the previous year. Draft thresholds are:
Green: QoQ change is positive (ie more violations previously than in the last quarter) AND count of violations per movement (all ATMs) is less than 0.03%
Amber: QoQ change is positive AND count of violations per movement (all ATMs) is higher than 0.03%
Amber: QoQ change is 0 ie same number of violations as before
Amber: QoQ change is negative (ie more violations in the last quarter than in the previous equivalent quarter) AND count of violations per movement (all ATMs) is less than 0.03%
Red: QoQ change is negative AND count of violations per movement (all ATMs) is higher than 0.03%
The number inside the dot represents the ranking position of a given airline in the given metric. The ranking position of an operator is driven by the relative performance of the given operator against the best and worst performer in the given metric.
Why can an airline have an amber status and still be high up the table?
Why do some airlines appear with ‘short haul’ or ‘long haul’?
The seven metrics
Each metric is assigned a “RAG” (Red, Amber, Green) status based on the performance bands set for that indicator. As a result operators towards the top of the table will typically have more ‘green scores’ than those towards the bottom. Individual metric scores will not be published. The metrics below make up the Fly Quiet and Green League Table.
Where the table shows amber dots, the airlines have met Heathrow’s minimum performance targets and green dots show they have exceeded them. If the airline has a red dot in a particular area, we work closely with them to improve performance.
1. Noise quota/seat
2. Chapter number (noise certification)
For more information on Chapter number charging categories please refer to Heathrow’s Conditions of Use (visit heathrow.com and search for “Conditions of Use”).
|Chapter number||3||4 High||4 Base||14 High||14 Base||14 Low|
The points above are adjusted by a factor of 1.5 and a factor of 2 for evening (19:00-23:00 local time) and night (23:00-07:00 local time) periods respectively.
3. NOx emissions/seat
4. CAEP standard (engine emissions certification)
5. Continuous Descent Approach (CDA) violations
6. Track keeping (TK) violations
Following detailed analysis with British Airways and NATS, we are aware that not all instances of aircraft that are off-track for reasons outside of the airlines control, are removed from the calculation. Over the coming months we will be working to address this issue.