This section has an overview of the monitoring requirements. It has included much information which is specific to large emitters and does not apply to small emitters. Checklist showing excatly what information you need to record will be available on our Checklists & Guides section. Guidance on what Procedures need to be written, and how to write them, can be found here.



All Operators are responsible for monitoring their own emissions every year. The European Commission has published two sets of Monitoring and Reporting Guidelines (MRG) for Operators to help them meet their responsibilities under the scheme. MRG2:2007 covers all industries, and contains the general rules which every Operator must obey. MRG2:2009 is specific to aviation, but Aircraft Operators must follow the relevant sections of both of these documents (a consolidated version is available here)


Emissions are measured using fuel burn rates, with an emissions factor applied to convert fuel use into the amount of carbon actually released into the atmosphere. The current emissions factor is 3.15 for Jet A-1, and 3.10 for Avgas; fuel specific factors need to be determined for non-standard fuels such as blends and bio-fuels.


To calculate the amount of CO2 emitted, large emitters have to multiply the amount of fuel burnt on a flight (determined to the specified degree of accuracy) by the relevant emissions factor. Fuel used in the APU must also be included. The Aviation MRG allows two ways to determine the amount of fuel used on each flight:


Method A:

Actual fuel consumption for each flight (tonnes) =

Amount of fuel contained in aircraft tanks once fuel uplift for the flight is complete (tonnes)


Amount of fuel contained in aircraft tanks once fuel uplift for subsequent flight is complete (tonnes)


Fuel uplift for that subsequent flight (tonnes)


Method B:

Actual fuel consumption for each flight (tonnes) =

Amount of fuel remaining in aircraft tanks at block-on at the end of the previous flight (tonnes


Fuel uplift for the flight (tonnes)


Amount of fuel contained in tanks at block-on at the end of the flight (tonnes)


The fuel figures cannot be rounded as they are being recorded, even if this is the existing standard practice as it does not provide the required accuracy to meet legal compliance; so as the pilot notes down the actual fuel levels, they must be as precise as possible, including significant decimal places. Emissions related figures are not rounded up until the final aggregated tonnes of CO2 are determined for the Operator.


Larger emitters are held to higher levels of accuracy. So if an Operator emits ≥ 50 kilotonnes of CO2 (the equivalent of burning roughly 15,870 tonnes of fuel), it is expected to have inherent design uncertainty levels on its measurement systems of ±2.5%, whereas those who emit less are allowed to work with ±5.0% inherent uncertainty.


The simplified method, which smaller non-commercial Operators are allowed to use, can be any system approved by the European Commission, but currently the only approved method is the Small Emitters Tool. This is an excel based tool which uses known fuel burn rates for generic aircraft types to estimate the fuel burn for individual flights. Operators using this tool are required to monitoring the distance of each flight, and have to manually input this information into the tool to produce emissions data (there is a significant amount of confusion surrounding the use of GCD's as the distance, but the legislation makes no reference to using it, and the UK Environment Agency require actual distances to be used if they are available).


This is not the same system as the ETS Support Facility which is a service offered by Eurocontrol which use distances they have monitored (including corrections if the aircraft deviates from the planned route), and prepares a report using the same fuel burn model as the Small Emitters Tool (and therefore fall under their approval)


The simplified method cannot be used to monitor tonne-km data. In order to claim free allowances, an Operator must monitor their tonne-km data for one calendar year. This involves recording the payload of every flight (in the case of passengers, a standard 100 kg, including luggage may be used, but actual weight will be more accurate and may be used if the Operator wishes). This weight is multiplied by the distance flown. The distance is always calculated using the great circle distance between the airports, plus 95km, irrespective of the actual route taken. Operators should be careful not to multiply the total tonnage for the year by the total distance, as this produces a different result compared to a flight by flight basis and totalling the results.


Once the data has been collected, it must be verified by an independent accredited verification body and submitted to the Competent Authority before March 31st of the following year.