Specific turboprop aircraft

The category transport/plane/specific/turboprop contains data on the fuel consumption and CO₂ emissions of 26 types of turboprop-engine aircraft, sourced from the EMEP/CORINAIR Emission Inventory Guidebook (2007).

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The methodology

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 fuel_{486 km} = fuel_{250 km} + ((fuel_{500 km} - fuel_{250 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 = (fuel_{taxi out} + fuel_{take off} + fuel_{climb out} + fuel_cruise + fuel_approach + fuel_{taxi in}) * 3.15 * quantity

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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 latitude/longitude or IATA code profile item values are specified, CarbonKit calculates the flight distance as the great circle distance between the two locations, inflating by 9% to account for congestion and indirect routing. If a distance is specified which is beyond the range of a given aircraft type, CarbonKit will return a zero value and a notification comment.

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