Operational Performance vs. Environmental CO2 Footprint for Different Commercial Turbofan Aircraft -

Comparison of Environmental Footprint Of Different Turbofan Power Plants For Super Jumbo, Ultra Long, HH, XR, LR, Mid-Sized Super Mid-Sized and Executive Liners Over a 10,000 km Range.

by Pedro Baldó

When you look at the following graphs, please remember that: 1 One litre of gasoline to 21.25 km for the Toyota Prius (Light Car) vs. 1 litre of gasoline to 7.65 km for the Chevy Suburban (SUV).

2 For every litre of gasoline burnt, approximately 2.4 kg. CO2 is produced.

So a light car on a 10,000 km journey, would produce around: 1,130 Kg. CO2 ~ or 1.13 metric tonnes CO2. A SUV would produce, according to this calculation: 3,137 Kg. CO2 ~ or 3.14 metric tonnes CO2. (this could be as high as 5.534 tonnes (metric) CO2 , depending on the ISA conditions).

3 The most efficient of turbofans, GE CFM LEAP Engines, with thrusts of up to 29,300 lbsf (130 kN), sfc ( kg/N.hr ): 0.04490 and Specific Thrusts (N.s/kg) of 1603.52 have a fuel burn ratio of 6.69 litres/100 km, or a fuel consumption of 245.26 gph, giving us, for a twin engined Boeing BBJ 787 Max-9, a: 27,242 lts fuel x 26.06 gr. CO2 / km. x 944.64 km./hr. x 10 hr.

(0.803 kg/lt) ~ or 5.385 (metric) tonnes of CO2. But the Boeing is carrying 220 passengers, against the two or three passengers the car would in comparison comfortably carry.

4 Then you can begin to get a grasp of the CO2 pollution bubbles for each of the powerplants examined.

CAEP/6 limits are exceeded by all of these aircraft. This means they are operating in an ENVIRONMENTALLY HARMFUL manner, if carrying more passengers than the yellow bar denotes (for each of them). These aircraft all have thrusts between 18,500 lbs f (82.3 kN) - FADEC GE CF-34 10E7-B - & 76,000 lbs f (338.07 kN) - RR Trent 100 / GE nX -1B -, per engine. All are twin-engined turbo fan jets but for the ¨quads¨ ACJs- 380 -841/842/861 operated by RR Trent 970-84 / RR Trent 972-84 & IAE Engine Alliance GP7200 rated at 78,303.2 lbs f (348.32 kN) / 80,214.06 lbs f (356.82 kN) and 74,735.47 lbs f (332.45 kN); that`s x 4 : 313,212.8 lbs f (1,393.29 kN) / 320,856.24 lbs f (1,427.29 kN) and 298,941.9 lbs f (1,329.81 kN), respectively, generating more than 211,339 lts fuel * 58.23 gr. CO2 / km * 979.2 km/hr * (10 hr)* (0.803) kg/lt = 96.8 tonnes (metric) of CO2. This could go up to 114.0 tonnes (metric), including take-off and landing.

All CAEP/6 limits KEPT by these aircraft. This means they are operating in an ENVIRONMENTALLY SAFE manner, if carrying passengers within what the yellow bar denotes. These aircraft all have thrusts between 18,500 lbs f (82.3 kN) - FADEC GE CF-34 10E7-B - and 33,000 lbs f (146.76 kN) - CFM LEAP / PW 1400G -, per engine. All are twin-engined turbofans, generating in the case of the ACJ 319 neo (fitted with two (2) CFM LEAP-1A / PW 1100G (22,100 lbs f (98.28 kN)), each, generating more than 82,603 lts fuel * 22.89 gr. CO2 / km * 813.98 km/hr * (10 hrs)* (0.803) kg/lt = 12.36 tonnes (metric) of CO2. This could go up to 15.05 tonnes (metric), including take-off and landing. These values extrapolated over 10,000 km give us between 14.86 - 18.10 metric tonnes so that we may compare values over the same range (distance), for different aircraft.

All CAEP/6 limits are KEPT by these aircraft within a VERY COMFORTABLE MARGIN. So they operate in an ENVIRONMENTALLY SAFE manner, carrying the people they were designed to carry. These aircraft all have thrusts between 7,580 lbs f (33.71 kN) - AE3007 A1E/3- & 23,000 lbs f (102.29 kN) - PW 1923G -, per engine. All are twin-engined powered turbofans, generating in the case of the E 190 E2 (fitted with two (2) PW 1923 Gs), more than 34,193 lts fuel * 4.74 gr. CO2 / km * 908.80 km/hr * (10 hrs)* (0.803) kg/lt = 1.18 tonnes (m) of CO2. This could go up to 1.42 tonnes (m), including take-off and landing. The equivalent kg. CO2 produced over a 10,000 km stretch (which it cannot cover in one leg, since fuel runs short at this range !!), would be approximately 10% more pollutant, that´s 1.30 – 1.56 tonnes (m) CO2, placing these aircraft in a class by themselves, compared to the other HEAVY LONG HAULERS. Even though they can transport 4 times less people, their cut in pollution is over 70 fold over the same distance, when compared to the SUPER JUMBO, HH LR, XL TWIN JET TURBOFANS & MID SIZE AIRLINERS At least 5 times less polluting than their big cousins. Matter of fact, their CAEP limit % is on average 500 % BELOW the CAEP/6 limit (see the attached graph).

All CAEP/6 limits KEPT by these aircraft. This means they are operating in an ENVIRONMENTALLY SAFE manner, if carrying passengers within what the yellow bar denotes and for the passenger capacity they were originally designed for. These aircraft all have thrusts between 14,750 lbs f (65.6 kN) - BR710 A2-20 / Pearl - and 18,920 lbs f (82.3 kN) - BR710 A2-20 / Pearl-, per engine. All are twin-engined turbofans, (each generating, in the case of the Dassault Falcon 10X (fitted with two (2) RR Pearl 15 (18,250 lbs f (81.16 kN)), more than 41,856 lts fuel * 8.79 gr. CO2 / km * 1,065 km/hr * (10 hrs)* (0.803) kg/lt = 3.15 tonnes (metric) of CO2. This could go up to 3.77 tonnes (metric), including take-off and landing.

All CAEP/6 limits KEPT by these aircraft, with the exception of the Dassault Falcon 900 LX EASy, and the Citation Longitude (very small infringement, almost negligible!! … though it is supposed to fly with a maximum of 12 people, it goes over the CAEP/6 limit with 8). This means they are operating in an ENVIRONMENTALLY SAFE manner, if carrying passengers within what the yellow bar denotes and for the passenger capacity they were originally designed for. These aircraft all have thrusts between 7,624 lbs f (33.91 kN) – HTF 7,250G, for the Gulfstream 300 and 14,000 lbs f (62.26 kN) – PW 812D, for the Dassault Falcon 6X -, per engine. All are twinengined high by-pass ratio turbofans, (generating each, in the case of the Dassault Falcon 6X (fitted with two (2) PW 812D, 14,000 lbs f (62.26 kN)), (as seen before), more than 19,085 lts fuel * 2.49 gr. CO2 / km * 1,037 km/hr * (10 hrs) * (0.803) kg/lt = 0.40 tonnes (metric) of CO2. This could go up to 0.48 tonnes (metric), including take-off and landing. These values are taken over a 10,000 km range to give us a common yardstick to measure values over the same distance, so that we may compare the performance of the different aircraft side by side. The real problem with these power plants is not the CO2 generated, as can be seen, but the NOx, because of the high temperatures at the inlet to the hp turbine. We can look at this issue in another report.