CO2 emissions are calculated by considering the fuel consumed during the discrete in-flight phases of "cruising" and the "landing-take off (LTO) cycle".
As with jet aircraft, fuel consumed by turboprop aircraft during "cruising" (i.e. at an altitude greater than 1000 m) is dependent on the distance flown. In addition, however, the fuel used during the 'taxiing out', 'take off' and 'climb out' phases of the LTO cycle are also related to flight distance for turboprop aircraft, reflecting the greater fuel requirements of flying longer distances which exerts an appreciable loading effect relative to turboprop aircraft sizes. CORINAIR provides fuel consumption data for taxiing out, take off, climb out and cruising for each aircraft type in discrete distance categories. Following CORINAIR methodology, CarbonKit interpolates between appropriate distance categories in order to calculate the specific fuel consumption for a given distance. For example, the fuel consumed during the cruise phase of a 486 km flight would be calculated by interpolating between the fuel consumption values for 250 km and 500 km, according to:
cruise fuel486 km = fuel250 km + ((fuel500 km - fuel250 km)*(486-250)/(500-250))
Fuel consumed during the taxi out, take off and climb out phases are calculated similarly, using the appropriate CORINAIR data tables. Fuel consumed during the 'approach' and 'taxiing in' phases of the LTO cycle are not related to the distance flown, and therefore remain constant for a given aircraft type. Total CO2 emissions are calculated by combining the fuel consumption associated with the LTO and cruising phases and multiplying by a CO2 emissions factor of 3.15 (kg CO2 per kg) and the quantity of flights under consideration.
CO2 = (fueltaxi out + fueltake off + fuelclimb out + fuelcruise + fuelapproach + fueltaxi in) * 3.15 * quantity
Using this methodology
Choosing a specific activity type
To use this category, select the aircraft type via the aircraft drill-down
Activity data required
Users can specify the flight distance by setting one of three profile item value groups:
- distance (directly sets the distance flown)
- lat1, long1, lat2, long2 (latitude and longitude values for arrival and departure locations)
- IATACode1, IATACode 2 (IATA codes for arrival and departure airports)
If appropriate, the journeys profile items can be additionally set, but will otherwise default to 1.
Users can elect to incorporate the RFI by setting the useRFI profile item value to "true", and entering a value for RFI in the radiativeForcingIndex profile item value. If no value is entered in the radiativeForcingIndex profile item value, a default factor of 1.9 will be applied (to cruise emissions only). For more information on RFI, see the here.
Calculation and result
The returned quantities for this methodology represent CO2, emissions associated with the aircraft and distance specified. The following amounts are returned:
- cruiseCO2: CO2 emissions associated with cruising at altitude
- taxiOutCO2: CO2 emissions associated with taxiing before take off
- takeOffCO2: CO2 emissions associated with the take off phase
- climbOutCO2: CO2 emissions associated with the climb out phase
- approachCO2: CO2 emissions associated with the approach phase
- taxiInCO2: CO2 emissions associated with taxiing subsequent to landing
- totalCO2: All CO2 emissions
- greatCircleDistance: calculated great circle distance in kms