Fuel economy in aircraft: Difference between revisions

Content deleted Content added

Inline

Revision as of 15:52, 8 October 2017

Fuel economy is a measure of how much fuel an aircraft, or a fleet of aircraft of mixed types, needs to operate in relation to a service provided (i.e. number of passengers or ton of freight) and the distance between points of travel. It can be expressed in several ways, for example by the litres of fuel consumed per passenger per kilometer.

Flight efficiency theory

A powered aircraft counters its weight through aerodynamic lift and counters its aerodynamic drag with thrust. The aircraft's maximum range is determined by the level of efficiency with which thrust can be applied to overcome the aerodynamic drag.

Aerodynamics

A subfield of fluid dynamics, aerodynamics studies the physics of a body moving through the air. As lift and drag are a function of air speed, their relationships are major determinants of an aircraft's design efficiency.

Aerodynamic drag comes from parasitic drag and lift-generated induced drag. Maximizing lift-to-drag ratio augments the aircraft efficiency, and this is attained by minimizing either. As parasitic drag increases with speed and induced drag decreases simultaneously, there is an optimum speed where the sum of both is minimal; this is the best glide ratio. For powered aircraft, the optimum glide ratio has to be balanced with thrust efficiency.

Parasitic drag is constituted by form drag and skin friction drag, and grows with the square of the speed in the drag equation. The form drag is minimized by having the smallest frontal area and by streamlining the aircraft for a low drag coefficient, and skin friction is proportional to the body's surface and can be reduced by maximizing laminar flow.

Induced drag can be reduced by decreasing the size of the airframe, fuel and payload weight, and by increasing the wing aspect ratio or by using wingtip devices, at the cost of increased structure weight.

Design Speed

By increasing efficiency, a lower cruise speed augments the range and reduces the environmental impact of aviation, however, a higher cruise speed allows more revenue passenger mile flown per day.

Jet engine efficiency increases with velocity because the speed difference between the flight and the exhaust is lower. However, above the drag divergence Mach number, the aerodynamic drag on the airframe overwhelms this effect because supersonic shockwaves begin to form, greatly increasing drag and needing supercritical airfoil designs for transonic flight.

For supersonic flight, drag increases at Mach 1.0 but decrease again after the transition. With a specifically designed aircraft, such as the (in development) Aerion AS2, the Mach 1.1 range at 3,700 nmi is 70% of the maximum range of 5,300 nmi at Mach 0.95, but increases to 4,750 nmi at Mach 1.4 for 90% before falling again.^[1]

Wingtip devices

Wingtip devices increase the effective wing aspect ratio, lowering lift-induced drag caused by wingtip vortices and improving the lift-to-drag ratio without increasing the wingspan often limited by the available width by the ICAO Aerodrome Reference Code. Airbus has installed wingtip fences on its planes since the A310-300 in 1985, and used today on the A320, A330/A340 and A380. Sharklet blended winglet for the A320 were launched during the November 2009 Dubai air show; their installation adds 200 kilograms (440 lb) but offers a 3.5% fuel burn reduction on flights over 2,800 km (1,500 nmi)^[2]

Weight

As the weight indirectly generates lift-induced drag, its minimization leads to a better aircraft efficiency. For a given payload, a lighter airframe generates a lower drag, and minimizing weight can be done through its configuration, materials science and construction methods. To obtain a longer range, a larger fuel fraction of the maximum takeoff weight is needed, adversely affecting efficiency.

The deadweight of the airframe and fuel is non-payload that must be lifted to altitude and kept aloft, contributing to fuel consumption. A reduction in airframe weight enables the use of smaller, lighter engines, and the weight savings in both allow a smaller, lighter fuel load for a given range and payload. A rule-of-thumb is that a reduction in fuel consumption of about 0.75% results from each 1% reduction in weight.^[3]

The 84 ton maximum payload of a modern Airbus A380 represents 14.6% of its 575 ton maximum take-off weight. There remains considerable room for future improvements in fuel efficiency. The weight of an aircraft can be reduced by using light-weight materials such as titanium, carbon fiber, and other composite plastics. Expensive materials may be used if the reduction of mass justifies the price of materials through improved fuel efficiency. The improvements achieved in fuel efficiency by mass reduction, reduce the amount of fuel an aircraft must carry. This further reduces the mass of the aircraft, and therefore provides further gains in fuel efficiency. For example, the Airbus A380 design includes multiple light-weight materials. The Boeing 787 Dreamliner was the first major commercial airplane to have a composite fuselage, composite wings, and use composites in most other airframe components.^[4]

Flight distance

For very long haul flights, the airplane is heavier to transport additional fuel, leading to a higher fuel consumption. Above a certain distance, it becomes more fuel efficient to make a halfway stop to refuel even if it leads to an additional less efficient descent and climb. For example, for a Boeing 777-300 the tipping point is at 3,000 nautical miles (5,600 km): it is more fuel efficient to make a non-stop flight below this distance and to make a stop above.^[5]

Very long non-stop flights suffer from the weight penalty of the large quantity of fuel required; this means limiting the number of available seats to compensate. For such flights, the critical fiscal factor is the quantity of fuel burnt per seat-nautical mile.^[6] For these reasons the world's longest commercial flights were cancelled circa 2013. An example is Singapore Air's former New York to Singapore flight, which could carry only 100 passengers (all business class) on the 10,300 mile flight. According to an industry analyst, "It [was] pretty much a fuel tanker in the air."^[7]

Propulsive efficiency

To get thrust, and aircraft engine is either a shaft engine - piston engine or turboprop, with its efficiency measured by its brake specific fuel consumption - coupled with a propeller having its own propulsive efficiency; or a jet engine with its efficiency measured by its thrust specific fuel consumption.

Turboprops have an optimum speed below 460 miles per hour (740 km/h).^[8] This is less than jets used by major airlines today, but the decrease in speed reduces drag.

Jet fuel cost and emissions reduction renew interest in the propfan concept for jetliners with an emphasis on engine/airframe efficiency that might come into service beyond the Boeing 787 and Airbus A350XWB. For instance, Airbus has patented aircraft designs with twin rear-mounted counter-rotating propfans.^[9] Propfans are a more fuel efficient technology than jet engines or turboprops. NASA has conducted an Advanced Turboprop Project (ATP), where they researched a variable pitch propfan that produced less noise and achieved high speeds.

Exploitation

Speed

The maximum range speed is when the ratio between velocity and drag is minimal,^[10] while maximum endurance is attained at the best lift/drag ratio.

Altitude

Pressure in the International Standard Atmosphere decreases with the altitude, thus lowering drag while also lowering lift, meaning a powered aircraft needs to fly at a higher speed to avoid stalling. With lower pressure aircraft engines lose power, requiring a turbocharger to maintain power for a piston engine, but lower temperatures also increases thermal efficiency.

Airlines

Fuel economy in air transport comes from aircraft fuel efficiency combined with airlines efficiency: seating configuration, passenger load factor and air cargo. For instance, over the transatlantic route, the most active intercontinental market, in 2014 the average fuel consumption was 32 pax-km per L - 3.13 litres per 100 kilometres (75 mpg_‑US) per passenger. The most fuel efficient airline was Norwegian Air Shuttle with 40 pax-km/L - 2.5 litres per 100 kilometres (94 mpg_‑US) per passenger, thanks to its fuel efficient Boeing 787-8, a high 86% passenger load factor and a high density of 1.18 seat/m² due to a low 11% premium seating. On the other side, the least efficient was British Airways at 27 pax-km/L - 3.7 litres per 100 kilometres (64 mpg_‑US) per passenger, using fuel inefficient Boeing 747-400s with a low density of 0.79 seat/m² due to a high 24% premium seating, in spite of a high 83% load factor.^[11]

MSCI ranked Ryanair as the lowest emissions intensity airline in its ACWI index with 75g CO2-e/revenue passenger kilometre in 2014, below Easyjet at 82g, the average at 123g and Lufthansa at 132g, by using high density 189 seats Boeing 737-800 ; in 2015 Ryanair emitted 8.64 Bn t of CO2 for 545,034 sectors flown : 15.85 t per 776 mi (674 nmi; 1,249 km) average sector (or 5.04 t of fuel : 4.04 kg/km) representing 95 kg per 90.6 Mn passengers (30.4 kg of fuel : 3.04 L/100km or 76 gCO2/km).^[12]

The Aeroflot Group fuel consumption is 22.9g/ASK, or 2.86 L/100 km (82 mpg_‑US) per seat, 3.51 L/100 km (67.0 mpg_‑US) per passenger at its 81.5% load factor.^[13] In 2016, Cathay Pacific and Cathay Dragon consumed 4,571,000 tonnes of fuel to transport 123,478 million revenue passenger kilometers, or 37 g/RPK, 25% better than in 1998: 4.63 L/100 km (50.8 mpg_‑US).^[14]

Among major airlines, those with turboprop equipped regional carrier subsidiaries typically rank high in overall fleet fuel efficiency. For example, although Alaska Airlines scored at the top of a 2011-2012 fuel efficiency ranking, if its regional carrier—turbo-prop equipped Horizon Air—were dropped from the consideration, the airline's ranking would be lower.^[15]

Operations

Airbus presented the following measures to save fuel, in its example of an A330 flying 2,500 nautical miles (4,600 km) like Bangkok-Tokyo: direct routing saves 190 kg (420 lb) fuel by flying 40 km (25 mi) less; 600 kg (1,300 lb) more fuel is consumed if flying 600 m (2,000 ft) below optimum altitude without vertical flight profile optimization; cruising 0.01 mach above optimum consumes 800 kg (1,800 lb) more fuel; 1,000 kg (2,200 lb) more fuel on board consumes 150 kg (330 lb) more fuel or 100 litres (22 imp gal; 26 US gal) of unused potable water consumes 15 kg (33 lb) more fuel.^[16]

Operational procedures can save 35 kg (77 lb) fuel by using the APU 10 minutes less, 15 kg (33 lb) with a reduced flap approach and 30 kg (66 lb) with reduced thrust reversal.^[16] Maintenance saves fuel as well: 100 kg (220 lb) more fuel is consumed without an engine wash schedule; 50 kg (110 lb) with a 5 mm (0.20 in) slat rigging gap, 40 kg (88 lb) with a 10 mm (0.39 in) spoiler rigging gap, 15 kg (33 lb) with a damaged door seal.^[16]

History

Past

Modern jet aircraft have twice the fuel efficiency of the earliest jet airliners.^[17] Late 1950s piston airliners like the Lockheed L-1049 Super Constellation and DC-7 were 1% to 28% more energy intensive than 1990s jet airliners which cruise 40 to 80% faster.^[18] The early jet airliners were designed at a time when air crew labor costs were higher relative to fuel costs than today. Despite the high fuel consumption, because fuel was inexpensive in that era the higher speed resulted in favorable economical returns since crew costs and amortization of capital investment in the aircraft could be spread over more seat miles flown per day.^[19]

Today's turboprop airliners have better fuel efficiency than current jet airliners, in part because of their lower cruising speed and propellers that are more efficient than those of the 1950s-era piston-powered airlines.^[15]

Jet aircraft efficiency is improving: between 1960 and 2000 there was a 55% overall fuel efficiency gain (as compared to the Boeing 707).^[18] Most of the improvements in efficiency were gained in the first decade when jet craft first came into widespread commercial use. Between 1971 and 1998 the fleet-average annual improvement per available seat-kilometre was estimated at 2.4%. Nonetheless, from the 1960s to the present total fleet emissions of the greenhouse gas carbon dioxide have outpaced efficiency gains, due to growth in the air travel market.^[21]

Concorde, a supersonic transport, managed about 17 passenger-miles to the Imperial gallon, which is 16.7 L/100 km per passenger; similar to a business jet, but much worse than a subsonic turbofan aircraft. Airbus states a fuel rate consumption of their A380 at less than 3 L/100 km per passenger (78 passenger-miles per US gallon);^[22] however this is for an unspecified number and configuration of seats. The maximum configuration is 850 economy passengers, but with a typical 525-seat multi-class configuration the fuel consumption is "comparable to that of a B747-400ER and even about 15% worse than a B777-300ER on a passenger-mile basis."^[23]

Example values

The aviation fuel density used is 6.7 lb/USgal or 0.8 kg/l.

300 nautical miles (560 km)

model	first flight	seats	Fuel burn	Fuel per seat
ATR 42-500	1995	48	1.26 kg/km (4.5 lb/mi)	3.15 L/100 km (75 mpg_‑US)^[24]
ATR 72-500	1997	70	1.42 kg/km (5.0 lb/mi)	2.53 L/100 km (93 mpg_‑US)^[24]
Beechcraft 1900D (226nm)	1982	19	1.00 kg/km (3.56 lb/mi)	6.57 L/100 km (35.8 mpg_‑US)^[25]
Bombardier Dash 8 Q400	1998	78	2.16 kg/km (7.7 lb/mi)	3.46 L/100 km (68.0 mpg_‑US)^[26]
Dornier 228	1981	19	0.94 kg/km (3.3 lb/mi)	6.22 L/100 km (37.8 mpg_‑US)^[27]
Dornier 328	1991	30	1.10 kg/km (3.91 lb/mi)	4.57 L/100 km (51.5 mpg_‑US)^[28]
Embraer Brasilia	1983	30	0.92 kg/km (3.3 lb/mi)	3.82 L/100 km (61.6 mpg_‑US)^[29]
Pilatus PC-12 (500 nm)	1991	9	0.41 kg/km (1.5 lb/mi)	5.66 L/100 km (41.6 mpg_‑US)^[30]
Saab 340	1983	32	1.1 kg/km (3.9 lb/mi)	4.29 L/100 km (54.8 mpg_‑US)^[31]
Saab 2000	1992	50	1.75 kg/km (6.2 lb/mi)	4.39 L/100 km (53.6 mpg_‑US)^[32]

500–660 nautical miles (930–1,220 km)

model	first flight	seats	sector	Fuel burn	Fuel efficiency per seat
Airbus A319neo	2015	144	600 nmi (1,100 km)	2.93 kg/km (10.4 lb/mi)	2.04 L/100 km (115 mpg_‑US)^[33]
Airbus A319neo	2015	124	660 nmi (1,220 km)	2.82 kg/km (10 lb/mi)	2.82 L/100 km (83.5 mpg_‑US)^[34]
Airbus A320neo	2015	154	660 nmi (1,220 km)	2.79 kg/km (9.9 lb/mi)	2.25 L/100 km (104.7 mpg_‑US)^[34]
Airbus A321neo	2015	192	660 nmi (1,220 km)	3.30 kg/km (11.7 lb/mi)	2.19 L/100 km (107.4 mpg_‑US)^[34]
Boeing 737-300	1984	126	507 nmi (939 km)	3.49 kg/km (12.4 lb/mi)	3.46 L/100 km (68 mpg_‑US)^[35]
Boeing 737-600	1998	110	500 nmi (930 km)	3.16 kg/km (11.2 lb/mi)	3.59 L/100 km (65.5 mpg_‑US)^[36]
Boeing 737-700	1997	126	500 nmi (930 km)	3.21 kg/km (11.4 lb/mi)	3.19 L/100 km (74 mpg_‑US)^[36]
Boeing 737 MAX 7	2017	128	660 nmi (1,220 km)	2.85 kg/km (10.1 lb/mi)	2.77 L/100 km (84.8 mpg_‑US)^[34]
Boeing 737 MAX 7	2017	144	600 nmi (1,100 km)	2.94 kg/km (10.4 lb/mi)	2.04 L/100 km (115 mpg_‑US)^[33]
Boeing 737-800	1997	162	500 nmi (930 km)	3.59 kg/km (12.7 lb/mi)	2.77 L/100 km (85 mpg_‑US)^[36]
Boeing 737 MAX 8	2017	166	660 nmi (1,220 km)	3.04 kg/km (10.8 lb/mi)	2.28 L/100 km (103.2 mpg_‑US)^[34]
Boeing 737-900ER	2006	180	500 nmi (930 km)	3.83 kg/km (13.6 lb/mi)	2.66 L/100 km (88 mpg_‑US)^[36]
Boeing 737 MAX 9	2017	180	660 nmi (1,220 km)	3.30 kg/km (11.7 lb/mi)	2.3 L/100 km (103 mpg_‑US)^[34]
Boeing 757-200	1982	200	500 nmi (930 km)	4.68 kg/km (16.61 lb/mi)	2.91 L/100 km (80.7 mpg_‑US)^[37]
Boeing 757-300	1998	243	500 nmi (930 km)	5.19 kg/km (18.41 lb/mi)	2.66 L/100 km (88.4 mpg_‑US)^[37]
Bombardier CRJ1000	2009	100	500 nmi (930 km)	2.66 kg/km (9.4 lb/mi)	3.33 L/100 km (71 mpg_‑US) ^[38]
Bombardier CSeries 100	2013	115	600 nmi (1,100 km)	2.46 kg/km (8.7 lb/mi)	2.14 L/100 km (110 mpg_‑US)^[33]
Bombardier CSeries 300	2015	140	600 nmi (1,100 km)	2.68 kg/km (9.5 lb/mi)	1.92 L/100 km (123 mpg_‑US)^[33]
Bombardier CS100	2013	125	500 nmi (930 km)	2.57 kg/km (9.1 lb/mi)	2.57 L/100 km (92 mpg_‑US)^[39]
Bombardier CS300	2015	160	500 nmi (930 km)	2.85 kg/km (10.11 lb/mi)	2.23 L/100 km (105 mpg_‑US)^[40]
Bombardier Dash 8 Q400	1998	82	600 nmi (1,100 km)	1.83 kg/km (6.5 lb/mi)	2.79 L/100 km (84 mpg_‑US)^[41]
Embraer E-Jet E2-175	2020	88	600 nmi (1,100 km)	2.11 kg/km (7.5 lb/mi)	2.4 L/100 km (98 mpg_‑US)^[33]
Embraer E-Jet E2-190	2018	106	600 nmi (1,100 km)	2.45 kg/km (8.7 lb/mi)	2.32 L/100 km (101 mpg_‑US)^[33]
Embraer E-Jet E2-195	2019	132	600 nmi (1,100 km)	2.67 kg/km (9.5 lb/mi)	2.03 L/100 km (116 mpg_‑US)^[33]
Embraer E-Jet-190	2002	98	500 nmi (930 km)	2.98 kg/km (10.6 lb/mi)	3.81 L/100 km (61.7 mpg_‑US)^[42]
Saab 340	1983	31	500 nmi (930 km)	0.95 kg/km (3.4 lb/mi)	3.83 L/100 km (61.4 mpg_‑US)^[31]
Saab 2000	1992	50	500 nmi (930 km)	1.54 kg/km (5.5 lb/mi)	3.85 L/100 km (61.1 mpg_‑US)^[32]
Sukhoi SSJ100	2008	98	500 nmi (930 km)	2.81 kg/km (10.0 lb/mi)	3.59 L/100 km (65.5 mpg_‑US)^[42]

1,000 nautical miles (1,900 km)

model	first flight	seats	Fuel Burn	Fuel efficiency per seat
Airbus A319	1995	124	2.93 kg/km (10.4 lb/mi)	2.95 L/100 km (80 mpg_‑US)^[43]
Airbus A319Neo	2015	136	2.4 kg/km (8.6 lb/mi)	1.93 L/100 km (122 mpg_‑US)^[20]
Airbus A320	1987	150	3.13 kg/km (11.1 lb/mi)	2.61 L/100 km (90 mpg_‑US)^[43]
Airbus A321-200	1996	180	3.61 kg/km (12.8 lb/mi)	2.5 L/100 km (94 mpg_‑US)^[43]
Airbus A330-200	1997	293	5.6 kg/km (19.8 lb/mi)	2.37 L/100 km (99 mpg_‑US)^[43]
Boeing 737-600	1998	110	2.77 kg/km (9.8 lb/mi)	3.15 L/100 km (75 mpg_‑US)^[36]
Boeing 737-700	1997	126	2.82 kg/km (10.0 lb/mi)	2.79 L/100 km (84 mpg_‑US)^[36]
Boeing 737-700	1997	128	2.8 kg/km (9.9 lb/mi)	2.71 L/100 km (87 mpg_‑US)^[43]
Boeing 737 MAX-7	2017	140	2.51 kg/km (8.91 lb/mi)	1.94 L/100 km (121 mpg_‑US)^[20]
Boeing 737-800	1997	162	3.17 kg/km (11.2 lb/mi)	2.44 L/100 km (96 mpg_‑US)^[36]
Boeing 737-800	1997	160	3.45 kg/km (12.23 lb/mi)	2.68 L/100 km (88 mpg_‑US)^[43]
Boeing 737-800W	1997	162	3.18 kg/km (11.3 lb/mi)	2.45 L/100 km (96 mpg_‑US)^[44]
Boeing 737 MAX-8	2017	162	2.71 kg/km (9.6 lb/mi)	2.04 L/100 km (115 mpg_‑US)^[44]
Boeing 737-900ER	2006	180	3.42 kg/km (12.1 lb/mi)	2.38 L/100 km (99 mpg_‑US)^[36]
Boeing 737-900ERW	2006	180	3.42 kg/km (12.1 lb/mi)	2.37 L/100 km (99 mpg_‑US)^[44]
Boeing 737 MAX-9	2017	180	2.91 kg/km (10.3 lb/mi)	2.02 L/100 km (116 mpg_‑US)^[44]
Boeing 757-200	1982	190	4.60 kg/km (16.33 lb/mi)	3.02 L/100 km (78 mpg_‑US)^[43]
Boeing 757-200	1982	200	4.16 kg/km (14.76 lb/mi)	2.59 L/100 km (90.8 mpg_‑US)^[37]
Boeing 757-300	1998	243	4.68 kg/km (16.62 lb/mi)	2.4 L/100 km (98 mpg_‑US)^[37]
Bombardier CS100	2013	125	2.28 kg/km (8.1 lb/mi)	2.28 L/100 km (103 mpg_‑US)^[39]
Bombardier CS300	2015	160	2.56 kg/km (9.08 lb/mi)	2.00 L/100 km (118 mpg_‑US)^[40]
Bombardier CS300	2015	135	2.30 kg/km (8.17 lb/mi)	1.85 L/100 km (127 mpg_‑US)^[20]
Quest Kodiak	2004	9	0.71 kg/km (2.52 lb/mi)	6.28 L/100 km (37.5 mpg_‑US)^[45]

2,160–3,000 nautical miles (4,000–5,560 km)

3,000 nautical miles (5,600 km) is typically transatlantic, e.g. New York JFK - London-Heathrow ^[46]

model	first flight	seats	sector	Fuel burn	Fuel per seat
Airbus A320	1987	150	2,151 nmi (3,984 km)	2.91 kg/km (10.3 lb/mi)	2.43 L/100 km (97 mpg_‑US)^[47]
Airbus A321NeoLR	2016	154	3,400 nmi (6,300 km)	2.99 kg/km (10.6 lb/mi)	2.43 L/100 km (97 mpg_‑US)^[48]
Airbus A330-200	1997	241	3,000 nmi (5,600 km)	6 kg/km (21 lb/mi)	3.11 L/100 km (76 mpg_‑US)^[49]
Airbus A330-300	1992	262	3,000 nmi (5,600 km)	6.25 kg/km (22.2 lb/mi)	2.98 L/100 km (79 mpg_‑US)^[49]
Airbus A330neo-900	2016	310	3,350 nmi (6,200 km)	6 kg/km (21 lb/mi)	2.42 L/100 km (97 mpg_‑US)^[50]
Airbus A340-300	1992	262	3,000 nmi (5,600 km)	6.81 kg/km (24.2 lb/mi)	3.25 L/100 km (72 mpg_‑US)^[49]
Boeing 737 MAX-8	2017	168	3,400 nmi (6,300 km)	2.86 kg/km (10.1 lb/mi)	2.13 L/100 km (110 mpg_‑US)^[51]
Boeing 737 MAX-9	2017	144	3,400 nmi (6,300 km)	2.91 kg/km (10.3 lb/mi)	2.53 L/100 km (93 mpg_‑US)^[48]
Boeing 747-400	1988	416	2,151 nmi (3,984 km)	10.77 kg/km (38.2 lb/mi)	3.24 L/100 km (73 mpg_‑US)^[47]
Boeing 747-8	2011	467	3,000 nmi (5,600 km)	9.9 kg/km (35 lb/mi)	2.65 L/100 km (89 mpg_‑US)^[52]
Boeing 757-200W	1981	158	3,400 nmi (6,300 km)	3.79 kg/km (13.4 lb/mi)	3 L/100 km (78 mpg_‑US)^[48]
Boeing 767-200ER	1984	181	3,000 nmi (5,600 km)	4.83 kg/km (17.1 lb/mi)	3.34 L/100 km (70 mpg_‑US)^[53]
Boeing 767-200ER	1984	193	3,400 nmi (6,300 km)	5.01 kg/km (17.8 lb/mi)	3.25 L/100 km (72 mpg_‑US)^[48]
Boeing 767-200ER	1984	224	3,000 nmi (5,600 km)	4.93 kg/km (17.5 lb/mi)	2.75 L/100 km (86 mpg_‑US)^[53]
Boeing 767-300ER	1988	218	2,151 nmi (3,984 km)	5.38 kg/km (19.1 lb/mi)	3.09 L/100 km (76 mpg_‑US)^[47]
Boeing 767-300ER	1988	218	3,000 nmi (5,600 km)	5.39 kg/km (19.1 lb/mi)	3.09 L/100 km (76 mpg_‑US)^[53]
Boeing 767-300ER	1988	269	3,000 nmi (5,600 km)	5.51 kg/km (19.5 lb/mi)	2.56 L/100 km (92 mpg_‑US)^[53]
Boeing 767-400ER	1999	245	3,000 nmi (5,600 km)	5.78 kg/km (20.5 lb/mi)	2.95 L/100 km (80 mpg_‑US)^[53]
Boeing 767-400ER	1999	304	3,000 nmi (5,600 km)	5.93 kg/km (21.0 lb/mi)	2.44 L/100 km (96 mpg_‑US)^[53]
Boeing 767-400ER	1999	304	3,265 nmi (6,047 km)	5.92 kg/km (21 lb/mi)	2.43 L/100 km (96.9 mpg_‑US)^[35]
Boeing 777-200	1994	305	3,000 nmi (5,600 km)	6.83 kg/km (24.2 lb/mi)	2.8 L/100 km (84 mpg_‑US)^[54]
Boeing 777-200ER	1996	301	3,000 nmi (5,600 km)	6.96 kg/km (24.7 lb/mi)	2.89 L/100 km (81 mpg_‑US)^[49]
Boeing 777-300	1997	368	3,000 nmi (5,600 km)	7.88 kg/km (28.0 lb/mi)	2.68 L/100 km (88 mpg_‑US)^[54]
Boeing 787-8	2009	291	3,400 nmi (6,300 km)	5.26 kg/km (18.7 lb/mi)	2.26 L/100 km (104 mpg_‑US)^[51]
Boeing 787-8	2009	238	3,400 nmi (6,300 km)	5.11 kg/km (18.1 lb/mi)	2.68 L/100 km (88 mpg_‑US)^[48]
Boeing 787-9	2013	304	3,350 nmi (6,200 km)	5.77 kg/km (20.5 lb/mi)	2.37 L/100 km (99 mpg_‑US)^[50]

5,000–7,600 nautical miles (9,300–14,100 km)

6,000 nautical miles (11,000 km) is typically transpacific, e.g. Hong kong international - San Francisco Intl^[55]

model	first flight	seats	sector	Fuel burn	Fuel per seat
Airbus A330-200	1997	241	6,000 nmi (11,000 km)	6.4 kg/km (23 lb/mi)	3.32 L/100 km (71 mpg_‑US)^[49]
Airbus A330neo-800	2017	248	4,650 nmi (8,610 km)	5.45 kg/km (19.3 lb/mi)	2.75 L/100 km (86 mpg_‑US)^[56]
Airbus A330neo-900	2017	300	4,650 nmi (8,610 km)	5.94 kg/km (21.1 lb/mi)	2.48 L/100 km (95 mpg_‑US)^[56]
Airbus A340-300	1992	262	6,000 nmi (11,000 km)	7.32 kg/km (26.0 lb/mi)	3.49 L/100 km (67.4 mpg_‑US)^[49]
Airbus A350-900	2013	315	4,972 nmi (9,208 km)	6.03 kg/km (21.4 lb/mi)	2.39 L/100 km (98 mpg_‑US)^[50]
Airbus A350-900	2013	315	6,542 nmi (12,116 km)	7.07 kg/km (25.1 lb/mi)	2.81 L/100 km (84 mpg_‑US)^[57]
Airbus A380	2005	525	7,200 nmi (13,300 km)	13.78 kg/km (48.9 lb/mi)	3.27 L/100 km (72 mpg_‑US)^[58]
Airbus A380	2005	544	6,000 nmi (11,000 km)	13.78 kg/km (48.9 lb/mi)	3.16 L/100 km (74 mpg_‑US)^[59]
Boeing 747-400	1988	416	6,000 nmi (11,000 km)	11.11 kg/km (39.4 lb/mi)	3.34 L/100 km (70 mpg_‑US)^[60]
Boeing 747-8	2011	467	6,000 nmi (11,000 km)	10.54 kg/km (37.4 lb/mi)	2.82 L/100 km (83 mpg_‑US)^[52]
Boeing 747-8	2011	405	7,200 nmi (13,300 km)	10.9 kg/km (39 lb/mi)	3.35 L/100 km (70 mpg_‑US)^[58]
Boeing 777-200ER	1996	301	6,000 nmi (11,000 km)	7.42 kg/km (26.3 lb/mi)	3.08 L/100 km (76 mpg_‑US)^[49]
Boeing 777-200ER	1996	301	6,000 nmi (11,000 km)	7.44 kg/km (26.4 lb/mi)	3.09 L/100 km (76 mpg_‑US)^[54]
Boeing 777-200LR	2005	291	4,972 nmi (9,208 km)	7.57 kg/km (26.9 lb/mi)	3.25 L/100 km (72 mpg_‑US)^[50]
Boeing 777-300ER	2003	365	6,000 nmi (11,000 km)	8.49 kg/km (30.1 lb/mi)	2.91 L/100 km (81 mpg_‑US)^[54]
Boeing 777-300ER	2003	344	7,200 nmi (13,300 km)	8.58 kg/km (30.4 lb/mi)	3.11 L/100 km (76 mpg_‑US)^[58]
Boeing 777-9X	2020	395	7,200 nmi (13,300 km)	9.04 kg/km (32.1 lb/mi)	2.85 L/100 km (83 mpg_‑US)^[58]
Boeing 787-8	2011	243	4,650 nmi (8,610 km)	5.38 kg/km (19.1 lb/mi)	2.77 L/100 km (85 mpg_‑US)^[56]
Boeing 787-9	2013	294	4,650 nmi (8,610 km)	5.85 kg/km (20.8 lb/mi)	2.49 L/100 km (94 mpg_‑US)^[56]
Boeing 787-9	2013	304	4,972 nmi (9,208 km)	5.63 kg/km (20.0 lb/mi)	2.31 L/100 km (102 mpg_‑US)^[50]
Boeing 787-9	2013	291	6,542 nmi (12,116 km)	7.18 kg/km (25.5 lb/mi)	3.08 L/100 km (76 mpg_‑US)^[57]

For comparison, a Volvo bus 9700 averages 0.41 litres per 100 kilometres (570 mpg_‑US) per seat for 63 seats.^[61] In highway travel an average auto has the potential for 1.61 litres per 100 kilometres (146 mpg_‑US)^[62] per seat (assuming 4 seats) and for a 5-seat 2014 Toyota Prius, 0.98 litres per 100 kilometres (240 mpg_‑US).^[63] While this shows the capabilities of the vehicles, the load factors (percentage of seats occupied) may differ between personal use (commonly just the driver in the car) and societal averages for long-distance auto use, and among those of particular airlines.

General aviation

For private aircraft in general aviation, the current official record (FAI "Efficiency Aircraft") is 37 km/kg fuel or 3.7 L/100 km in a Monnett Sonerai.^[64]

Future

NASA and Boeing flight tested a 500 lb (230 kg) blended wing body (BWB) X-48B demonstrator from August 2012 to April 2013. This design provides greater fuel efficiency, since the whole craft produces lift, not just the wings.^[65] The BWB concept offers advantages in structural, aerodynamic and operating efficiencies over today's more conventional fuselage-and-wing designs. These features translate into greater range, fuel economy, reliability and life cycle savings, as well as lower manufacturing costs.^[66]^[67] NASA has created a cruise efficient STOL (CESTOL) concept.

Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research (IFAM) have researched a shark skin imitating paint that would reduce drag through a riblet effect.^[68] Aircraft is a major potential application for new technologies such as aluminium metal foam and nanotechnology such as the shark skin imitating paint.

Multiple concepts are projected to reduce fuel consumption:^[69]

the Airbus/Rolls-Royce E-Thrust is an hybrid electric with a gas turbine engine and electric ducted fans with energy storage for peak power for takeoff and climb while for the descent the engine is shut down and the fans windmills to recharge the batteries;
Empirical Systems Aerospace (ESAero) develop the 150-seat ECO-150 concept for turboelectric distributed propulsion with two turboshaft engines mounted on the wing and driving generators powering ducted fans embedded in the inboard wing sections, effectively increasing the bypass ratio and propulsive efficiency for 20-30% fuel savings over the Boeing 737 NG, while providing some powered lift;
NASA’s single-aisle turbo-electric aircraft with an aft boundary layer propulsor (STARC-ABL) is a conventional tube and wing 737-sized airliner with an aft-mounted electric fan ingesting the fuselage boundary layer hybrid-electric propulsion;
The Boeing blended wing body (BWB) with a wide fuselage mated to a high-aspect-ratio wings is more aerodynamically efficient because the entire aircraft contributes to the lift and because it has less surface area, producing less drag and offering weight savings due to lower wing loading, and noise is shielded by locating the engines on the aft upper surface;
Developed with the U.S. Air Force Research Laboratory and refined with NASA, the Lockheed Martin Hybrid Wing Body (HWB) combines a blended forward fuselage and wing with a conventional aft fuselage and T-tail for compatibility with existing infrastructure and airdrop; the engines in overwing nacelles on struts over the trailing edge enable higher-bypass-ratio engines with 5% less drag, provide acoustic shielding and increases lift without a thrust or drag penalty at low speed;
Airbus-backed, German Bauhaus-Luftfahrt designed the Propulsive Fuselage concept reducing drag with a fan in the tail ingesting air flowing over the fuselage via an annular (ring-shaped) inlet and re-energizes the wake, driven with a gearbox or as a turbo-electric configuration;

Conceived by the Massachusetts Institute of Technology for NASA, Aurora Flight Sciences develop the double-bubble D8, a 180-seat aircraft with a wide lifting fuselage, twin-aisle cabin to replace A320 and B737 narrowbodies, and boundary-layer ingestion with engines in the tail driving distortion-tolerant fans for a 49% fuel-burn reduction over the B737NG;
The Boeing Truss-Braced wing (TBW) concept was developed for the NASA-funded Subsonic Ultra Green Aircraft Research program with an aspect ratio of 19.5 compared to 11 for the Boeing 787: the strut relieves some bending moment and a braced wing can be lighter than a cantilevered wing or longer for the same weight, having better lift-to-drag ratio by lowering the induced drag and thinner, facilitating natural laminar flow and reducing wave drag at transonic speeds;
Dzyne Technologies reduces the thickness of the blended wing body for a 110-130-seat super-regional, a configuration usually too thick for a narrowbody replacement and better suited for large aircraft, by placing the landing gear outward and storing baggage in the wing roots, enabling 20% fuel savings;
the French research agency ONERA designed two concepts for a 180-seat airliner Versitalie Aircraft (NOVA) including turbofans with higher bypass ratios and fan diameter: a gull wing with increased dihedral inboard to accommodate larger geared turbofans under without lengthening the gear and the other with engines embedded in the tail ingesting the low-energy fuselage boundary layer flow and reenergize the wake to reduce drag;
with Cranfield University, Rolls-Royce developed the Distributed Open Rotor (DORA) with high-aspect-ratio wing and V-tail to minimize drag, and turbogenerators on the wing driving electric propellers along the inboard leading edge with open rotor high propulsive efficiency and increasing the effective bypass ratio.

Research projects such as Boeing's ecoDemonstrator program have sought to identify ways of improving the fuel economy of commercial aircraft operations. The U.S. government has encouraged such research through grant programs, including the FAA's Continuous Lower Energy, Emissions and Noise (CLEEN) program, and NASA's Environmentally Responsible Aviation (ERA) Project.^{[citation needed]}

The IATA technology roadmap envisions improvements in aircraft Configuration and aerodynamics, from 2022: Natural Laminar flow would reduce Fuel consumption by 5 to 10% and Hybrid Laminar Flow by 10 to 15%, from 2026: Hybrid Wing Body by 10 to 25%, from 2027: Morphing Airframe by 5 to 10%, from 2028: Truss / Strut-Braced wing by 10 to 15%, from 2032: Flying without landing gear by 10 to 20% ; new engine architecture from 2016: Geared turbofan and Advanced Turbofan would reduce Fuel consumption by 10 to 15%, from 2019: Open rotor/Unducted Fan by 15 to 20%, from 2023: Counter rotating fan by 15 to 20%, from 2026: second generation core concepts by 25 to 30%.^[70]

References

^ "Performance > Speed". Aerion.
^ Max Kingsley-Jones (15 November 2009). "Dubai 09: A320s sharklets to deliver 3.5% lower fuel burn from 2012". Flight International.
^ Barney L. Capehart (2007). Encyclopedia of Energy Engineering and Technology. Vol. 1. CRC Press. ISBN 978-0-8493-3653-9.
^ Marsh, George (April 8, 2014). "Composites flying high (Part 1)". Materials Today. Retrieved May 23, 2015.
^ Antonio Filippone (2012). Advanced Aircraft Flight Performance. Cambridge University Press. p. 454. ISBN 9781139789660.
^ Park Y., O'Kelly M.E. (2014). Fuel burn rates of commercial passenger aircraft: variations by seat configuration and stage distance. Jrnl. Transp. Geog., 41:pp.137-147.
^ Why the Longest Nonstop Flights Are Ending, Bloomberg Bus., 31 Oct. 2013.
^ Spakovszky, Zoltan (2009). "Unified Propulsion Lecture 1". Unified Engineering Lecture Notes. MIT.
^ US application 2009020643, Airbus & Christophe Cros, "Aircraft having reduced environmental impact", published 2009-01-22
^ James Albright (Feb 27, 2016). "Getting the Most Miles from Your Jet-A". Business & Commercial Aviation. Aviation Week.
^ Irene Kwan and Daniel Rutherford (November 2015). "Transatlantic airline fuel efficiency ranking, 2014" (PDF). International Council on Clean Transportation.
^ "Annual Report" (PDF). Ryanair. July 2016. p. 29.
^ Bjorn Fehrm (April 26, 2017). "Aeroflot, the route to a modern airline. Part 3". Leeham Co.
^ "Sustainable Development Report 2016" (PDF). Cathay Pacific. p. 5.
^ ^a ^b Irene Kwan (3 June 2014). "Back to the Future: Return of the Turboprop?". The International Council on Clean Transport.
^ ^a ^b ^c Simon Weselby (October 2012). "Fuel Burn vs. Maintenance Costs" (PDF). IATA maintenance cost conference. Airbus.
^ "Efﬁciency Trends for New Commercial Jet Aircraft, 1960 to 2008" (PDF). The International Council on Clean Transportation. November 2009.
^ ^a ^b Peeters, P. M.; Middel, J.; Hoolhorst, A. (November 2005). "Fuel efficiency of commercial aircraft" (PDF). Netherlands National Aerospace Laboratory. An overview of historical and future trends.
^ Brian M. Yutko and R. John Hansman (May 2011). "Approaches to Representing Aircraft Fuel Efficiency. Performance for the Purpose of a Commercial Aircraft" (PDF). MIT International Center for Air Transportation.
^ ^a ^b ^c ^d "CS300 first flight Wednesday, direct challenge to 737-7 and A319neo". Leeham News. 25 February 2015.
^ Peeters, Kutzner & Cohen (2016). Are technology myths stalling aviation climate policy?. At 4-5.
^ "The A380: The future of flying". Airbus. Archived from the original on December 14, 2007. Retrieved 2008-03-22. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ Inflight Luxury: Who Really Pays?, Irene Kwan, ICCT. 30 May 2014.
^ ^a ^b "Fuel saving" (PDF). ATR. January 2011.
^ "Beechcraft 1900D: Fuel, Emissions & Cost Savings Operational Analysis" (PDF). Specific Range Solutions Ltd. February 21, 2012.
^ Mark Brouwer, Siddharth Srinivasan. "Proud to fly a Turboprop: Q400 vs ATR72". The Flying Engineer.
^ "Dornier 228 Advanced Commuter Brochure". RUAG.
^ "Dornier 328 corporate shuttle" (PDF). Aviation Week Business & Commercial Aviation. March 1996.
^ "120 Brasilia Sales Brochure". Embraer. p. 8.
^ "PC-12 NG Just The Facts" (PDF). Pilatus. 20 October 2015.
^ ^a ^b "Saab 340A data sheet" (PDF). Saab Aircraft Leasing. 2009.
^ ^a ^b "Saab 2000 data sheet" (PDF). Saab Aircraft Leasing. 2009.
^ ^a ^b ^c ^d ^e ^f ^g "Embraer continues and refines its strategy at the low-end of 100-149 seat sector". Leeham News. 13 January 2014.
^ ^a ^b ^c ^d ^e ^f "ANALYSIS: A320neo vs. 737 MAX: Airbus is Leading (Slightly) – Part II". Airways News. 5 February 2016.
^ ^a ^b Scott McCartney (Aug 12, 2010). "A Prius With Wings vs. a Guzzler in the Clouds". Wall Street Journal.
^ ^a ^b ^c ^d ^e ^f ^g ^h "737 performance summary" (PDF). Boeing. 2007. Archived from the original (PDF) on 2014-07-25. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ ^a ^b ^c ^d "757 performance summary" (PDF). Boeing. 2007.
^ "Bombardier CRJ1000 Fuel Consumption". Sun Airlines. 20 August 2013.
^ ^a ^b "CS100 environmental product declaration" (PDF). Bombardier. 2016-09-27.
^ ^a ^b "CS300 environmental product declaration" (PDF). Bombardier. 2017-09-27.
^ "Q400 Fuel efficiency manual" (PDF). Bombardier. 2014.
^ ^a ^b "Sukhoi SSJ100, Embraer ERJ190, Airbus A319 Operational and Economic Comparison". Sukhoi. March 2013.
^ ^a ^b ^c ^d ^e ^f ^g "Analysing the options for 757 replacement" (PDF). Aircraft Commerce. August 2005.
^ ^a ^b ^c ^d "Boeing 737 MAX: performance with reported engine SFC shortfall". Leeham News. 15 April 2015.
^ "Kodiak Brochure" (PDF). Quest Aircraft. April 2014.
^ "Distance from JFK to LHR". great circle mapper.
^ ^a ^b ^c Template:Cite article
^ ^a ^b ^c ^d ^e Bjorn Fehrm (25 February 2015). "Redefining the 757 replacement: Requirement for the 225/5000 Sector". Leeham News.
^ ^a ^b ^c ^d ^e ^f ^g "Boeing: 777 way much better than A330". Aspire aviation. 8 December 2010.
^ ^a ^b ^c ^d ^e Vinay Bhaskara (November 25, 2014). "UPDATED ANALYSIS: Delta Order for A350; A330neo Hinged on Pricing, Availability". Airways News.
^ ^a ^b "737 MAX 8 could be enabler for some LCC Long Haul". Leeham News. 8 December 2014.
^ ^a ^b "747-8 performance summary" (PDF). Boeing. 2010. Archived from the original (PDF) on 2014-07-24. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ ^a ^b ^c ^d ^e ^f "767 performance summary" (PDF). Boeing. 2006. Archived from the original (PDF) on 2015-04-15. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
^ ^a ^b ^c ^d "777 performance summary" (PDF). Boeing. 2009. Archived from the original (PDF) on 2014-01-04. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
^ "Distance from HKG to SFO". great circle mapper.
^ ^a ^b ^c ^d "ANALYSIS: The Boeing 787-8 and Airbus A330-800neo are Far From Dead". Airways News. March 17, 2016.
^ ^a ^b "Airbus A350: is the Xtra making the difference ?". Aspire Aviation. 8 June 2015.
^ ^a ^b ^c ^d "Updating the A380: the prospect of a neo version and what's involved". leeham news. 3 February 2014.
^ "What Might an Engine Improvement and Sharklets Provide?". Air Insight. July 4, 2016.
^ "747 performance summary" (PDF). Boeing. 2010. Archived from the original (PDF) on 2014-07-25. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ Edward Jobson (12 September 2013). "Coach fuel consumption". volvo buses.
^ DEFRA (2008). 2008 Guidelines to Defra’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors Archived 2012-01-05 at the Wayback Machine
^ "2014 Toyota Prius fuel economy". United States Environmental Protection Agency.
^ "FAI Record ID #15066 - Aeroplane Efficiency, C-1b (Landplanes: take off weight 500 to 1000 kg) " Fédération Aéronautique Internationale Record date 8 June 2008. Accessed: 4 October 2015.
^ Hank Green (October 8, 2007). "Fuel Efficient Plane Prototype Hits Skies". Ecogeek. Archived from the original on July 14, 2014. Retrieved July 6, 2014. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ Tom Koehler (October 27, 2006). "Boeing to Begin Ground Testing of X-48B Blended Wing Body Concept" (Press release). Boeing. Retrieved April 10, 2012.
^ Philip Lorenz III (July 3, 2007). "AEDC testing brings unique blended wing aircraft closer to flight". Arnold Air Force Base. Archived from the original on July 14, 2014. Retrieved April 10, 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ Mahony, Melissa (2010-05-25). "A sharkskin coating for ships, planes and blades". SmartPlanet. Retrieved 2012-09-29.
^ Graham Warwick (Jan 27, 2017). "When Will These Civil Aircraft Concepts Fly?". Aviation Week & Space Technology.
^ "Technology Roadmap" (PDF). IATA. 2013.

External links

James Albright (Feb 27, 2016). "Getting the Most Miles from Your Jet-A". Business & Commercial Aviation. Aviation Week.
Elyse Moody (Mar 1, 2012). "Focus On Fuel Savings". Overhaul & Maintenance. Aviation Week.
Scott W. Ashcraft, Andres S. Padron, Kyle A. Pascioni, and Gary W. Stout, Jr., Dennis L. Huff (October 2011). "Review of Propulsion Technologies for N+3 Subsonic Vehicle Concepts" (PDF). Glenn Research Center, Cleveland, Ohio. NASA.{{cite web}}: CS1 maint: multiple names: authors list (link)
"Technology Roadmap Annex" (PDF). IATA. 2009.

[1] "Performance > Speed". Aerion.

[2] Max Kingsley-Jones (15 November 2009). "Dubai 09: A320s sharklets to deliver 3.5% lower fuel burn from 2012". Flight International.

[Capehart-3] Barney L. Capehart (2007). Encyclopedia of Energy Engineering and Technology. Vol. 1. CRC Press. ISBN 978-0-8493-3653-9.

[Composites_flying_prt1-4] Marsh, George (April 8, 2014). "Composites flying high (Part 1)". Materials Today. Retrieved May 23, 2015.

[5] Antonio Filippone (2012). Advanced Aircraft Flight Performance. Cambridge University Press. p. 454. ISBN 9781139789660.

[6] Park Y., O'Kelly M.E. (2014). Fuel burn rates of commercial passenger aircraft: variations by seat configuration and stage distance. Jrnl. Transp. Geog., 41:pp.137-147.

[7] Why the Longest Nonstop Flights Are Ending, Bloomberg Bus., 31 Oct. 2013.

[8] Spakovszky, Zoltan (2009). "Unified Propulsion Lecture 1". Unified Engineering Lecture Notes. MIT.

[9] US application 2009020643, Airbus & Christophe Cros, "Aircraft having reduced environmental impact", published 2009-01-22

[10] James Albright (Feb 27, 2016). "Getting the Most Miles from Your Jet-A". Business & Commercial Aviation. Aviation Week.

[ICCT1511-11] Irene Kwan and Daniel Rutherford (November 2015). "Transatlantic airline fuel efficiency ranking, 2014" (PDF). International Council on Clean Transportation.

[12] "Annual Report" (PDF). Ryanair. July 2016. p. 29.

[13] Bjorn Fehrm (April 26, 2017). "Aeroflot, the route to a modern airline. Part 3". Leeham Co.

[14] "Sustainable Development Report 2016" (PDF). Cathay Pacific. p. 5.

[ICCT-Kwan-15] Irene Kwan (3 June 2014). "Back to the Future: Return of the Turboprop?". The International Council on Clean Transport.

[weselby2012-16] Simon Weselby (October 2012). "Fuel Burn vs. Maintenance Costs" (PDF). IATA maintenance cost conference. Airbus.

[17] "Efﬁciency Trends for New Commercial Jet Aircraft, 1960 to 2008" (PDF). The International Council on Clean Transportation. November 2009.

[Peeters-2005-18] Peeters, P. M.; Middel, J.; Hoolhorst, A. (November 2005). "Fuel efficiency of commercial aircraft" (PDF). Netherlands National Aerospace Laboratory. An overview of historical and future trends.

[19] Brian M. Yutko and R. John Hansman (May 2011). "Approaches to Representing Aircraft Fuel Efficiency. Performance for the Purpose of a Commercial Aircraft" (PDF). MIT International Center for Air Transportation.

[LH150225-20] "CS300 first flight Wednesday, direct challenge to 737-7 and A319neo". Leeham News. 25 February 2015.

[21] Peeters, Kutzner & Cohen (2016). Are technology myths stalling aviation climate policy?. At 4-5.

[22] "The A380: The future of flying". Airbus. Archived from the original on December 14, 2007. Retrieved 2008-03-22. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[23] Inflight Luxury: Who Really Pays?, Irene Kwan, ICCT. 30 May 2014.

[ATR-24] "Fuel saving" (PDF). ATR. January 2011.

[25] "Beechcraft 1900D: Fuel, Emissions & Cost Savings Operational Analysis" (PDF). Specific Range Solutions Ltd. February 21, 2012.

[26] Mark Brouwer, Siddharth Srinivasan. "Proud to fly a Turboprop: Q400 vs ATR72". The Flying Engineer.

[27] "Dornier 228 Advanced Commuter Brochure". RUAG.

[28] "Dornier 328 corporate shuttle" (PDF). Aviation Week Business & Commercial Aviation. March 1996.

[29] "120 Brasilia Sales Brochure". Embraer. p. 8.

[30] "PC-12 NG Just The Facts" (PDF). Pilatus. 20 October 2015.

[Saab340-31] "Saab 340A data sheet" (PDF). Saab Aircraft Leasing. 2009.

[Saab2000-32] "Saab 2000 data sheet" (PDF). Saab Aircraft Leasing. 2009.

[LH140113-33] ^ ^a ^b ^c ^d ^e ^f ^g "Embraer continues and refines its strategy at the low-end of 100-149 seat sector". Leeham News. 13 January 2014.

[AI160205-34] ^ ^a ^b ^c ^d ^e ^f "ANALYSIS: A320neo vs. 737 MAX: Airbus is Leading (Slightly) – Part II". Airways News. 5 February 2016.

[WSJ100812-35] Scott McCartney (Aug 12, 2010). "A Prius With Wings vs. a Guzzler in the Clouds". Wall Street Journal.

[737_perf-36] ^ ^a ^b ^c ^d ^e ^f ^g ^h "737 performance summary" (PDF). Boeing. 2007. Archived from the original (PDF) on 2014-07-25. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[757_passenger.pdf-37] "757 performance summary" (PDF). Boeing. 2007.

[38] "Bombardier CRJ1000 Fuel Consumption". Sun Airlines. 20 August 2013.

[CS100-39] "CS100 environmental product declaration" (PDF). Bombardier. 2016-09-27.

[CS300-40] "CS300 environmental product declaration" (PDF). Bombardier. 2017-09-27.

[41] "Q400 Fuel efficiency manual" (PDF). Bombardier. 2014.

[SSJ100-42] "Sukhoi SSJ100, Embraer ERJ190, Airbus A319 Operational and Economic Comparison". Sukhoi. March 2013.

[AC200508-43] ^ ^a ^b ^c ^d ^e ^f ^g "Analysing the options for 757 replacement" (PDF). Aircraft Commerce. August 2005.

[737max-44] "Boeing 737 MAX: performance with reported engine SFC shortfall". Leeham News. 15 April 2015.

[45] "Kodiak Brochure" (PDF). Quest Aircraft. April 2014.

[46] "Distance from JFK to LHR". great circle mapper.

[SEI200805-47] Template:Cite article

[LN150225-48] Bjorn Fehrm (25 February 2015). "Redefining the 757 replacement: Requirement for the 225/5000 Sector". Leeham News.

[AA101208-49] ^ ^a ^b ^c ^d ^e ^f ^g "Boeing: 777 way much better than A330". Aspire aviation. 8 December 2010.

[AN141125-50] Vinay Bhaskara (November 25, 2014). "UPDATED ANALYSIS: Delta Order for A350; A330neo Hinged on Pricing, Availability". Airways News.

[LN141208-51] "737 MAX 8 could be enabler for some LCC Long Haul". Leeham News. 8 December 2014.

[747-8_perf-52] "747-8 performance summary" (PDF). Boeing. 2010. Archived from the original (PDF) on 2014-07-24. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[767_perf-53] ^ ^a ^b ^c ^d ^e ^f "767 performance summary" (PDF). Boeing. 2006. Archived from the original (PDF) on 2015-04-15. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)

[777_perf-54] "777 performance summary" (PDF). Boeing. 2009. Archived from the original (PDF) on 2014-01-04. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)

[55] "Distance from HKG to SFO". great circle mapper.

[AN160317-56] "ANALYSIS: The Boeing 787-8 and Airbus A330-800neo are Far From Dead". Airways News. March 17, 2016.

[AA150608-57] "Airbus A350: is the Xtra making the difference ?". Aspire Aviation. 8 June 2015.

[LH140203-58] "Updating the A380: the prospect of a neo version and what's involved". leeham news. 3 February 2014.

[59] "What Might an Engine Improvement and Sharklets Provide?". Air Insight. July 4, 2016.

[60] "747 performance summary" (PDF). Boeing. 2010. Archived from the original (PDF) on 2014-07-25. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[61] Edward Jobson (12 September 2013). "Coach fuel consumption". volvo buses.

[62] DEFRA (2008). 2008 Guidelines to Defra’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors Archived 2012-01-05 at the Wayback Machine

[63] "2014 Toyota Prius fuel economy". United States Environmental Protection Agency.

[64] "FAI Record ID #15066 - Aeroplane Efficiency, C-1b (Landplanes: take off weight 500 to 1000 kg) " Fédération Aéronautique Internationale Record date 8 June 2008. Accessed: 4 October 2015.

[65] Hank Green (October 8, 2007). "Fuel Efficient Plane Prototype Hits Skies". Ecogeek. Archived from the original on July 14, 2014. Retrieved July 6, 2014. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[66] Tom Koehler (October 27, 2006). "Boeing to Begin Ground Testing of X-48B Blended Wing Body Concept" (Press release). Boeing. Retrieved April 10, 2012.

[67] Philip Lorenz III (July 3, 2007). "AEDC testing brings unique blended wing aircraft closer to flight". Arnold Air Force Base. Archived from the original on July 14, 2014. Retrieved April 10, 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[68] Mahony, Melissa (2010-05-25). "A sharkskin coating for ships, planes and blades". SmartPlanet. Retrieved 2012-09-29.

[69] Graham Warwick (Jan 27, 2017). "When Will These Civil Aircraft Concepts Fly?". Aviation Week & Space Technology.

[70] "Technology Roadmap" (PDF). IATA. 2013.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

@@ Line 387: / Line 387: @@
 | [[Boeing 737]]-900ER || 2006 || 180
 | {{convert|{{#expr:35.2*180/(1000*1.852)round2}}|kg/km|lb/mi|abbr=on}}
-| {{convert|{{#expr:35.2/.8/(10*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="737_perf">{{cite web
+| {{convert|{{#expr:35.2/.8/(10*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="737_perf">{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/737ng_perf.pdf |title= 737 performance summary |publisher= Boeing |date= 2007 |deadurl= yes |archiveurl= https://web.archive.org/web/20140725005129/http://www.boeing.com/assets/pdf/commercial/startup/pdf/737ng_perf.pdf |archivedate= 2014-07-25 |df=  }}</ref>
-|url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/737ng_perf.pdf |title= 737 performance summary |publisher= Boeing |date= 2007}}</ref>
 <!-- 35.2kg at .8kg/L for 1000nm * 1.852 nm per 100km -->
 |-
@@ Line 553: / Line 552: @@
 | [[Boeing 777]]-300 || 1997 || 368 || {{convert|3000|nmi|km|abbr=on}}
 | {{convert|{{#expr:118.9*368/(3000*1.852)round2}}|kg/km|lb/mi|abbr=on}}
-| {{convert|{{#expr:118.9/.8/(30*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="777_perf">{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/777_perf.pdf |archive-url= https://web.archive.org/web/20140104144441/http://www.boeing.com:80/assets/pdf/commercial/startup/pdf/777_perf.pdf |archive-date=2014-01-04 |dead-url= yes |title= 777 performance summary |publisher= Boeing |date= 2009}}</ref>
+| {{convert|{{#expr:118.9/.8/(30*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="777_perf">{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/777_perf.pdf |archive-url= https://web.archive.org/web/20140104144441/http://www.boeing.com/assets/pdf/commercial/startup/pdf/777_perf.pdf |archive-date= 2014-01-04 |dead-url= yes |title= 777 performance summary |publisher= Boeing |date= 2009 |df=  }}</ref>
 <!-- 118.9kg at .8kg/L for 3000nm * 1.852 nm per 100km -->
 |-
@@ Line 616: / Line 615: @@
 | [[Boeing 747-400]] || 1988 || 416 || {{convert|6000|nmi|km|abbr=on}}
 | {{convert|{{#expr:296.7*416/(6000*1.852)round2}}|kg/km|lb/mi|abbr=on}}
-|  {{convert|{{#expr:296.7/.8/(60*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref>{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/747_perf.pdf |title= 747 performance summary |publisher= Boeing |date= 2010}}</ref>
+|  {{convert|{{#expr:296.7/.8/(60*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref>{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/747_perf.pdf |title= 747 performance summary |publisher= Boeing |date= 2010 |deadurl= yes |archiveurl= https://web.archive.org/web/20140725002756/http://www.boeing.com/assets/pdf/commercial/startup/pdf/747_perf.pdf |archivedate= 2014-07-25 |df=  }}</ref>
 <!-- 296.7kg at .8kg/L for 6000nm * 1.852 nm per 100km -->
 |-
 | [[Boeing 747-8]] || 2011 || 467 || {{convert|6000|nmi|km|abbr=on}}
 | {{convert|{{#expr:250.8*467/(6000*1.852)round2}}|kg/km|lb/mi|abbr=on}}
-| {{convert|{{#expr:250.8/.8/(60*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="747-8_perf">{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/747-8_perf.pdf |title= 747-8 performance summary |publisher= Boeing |date= 2010}}</ref>
+| {{convert|{{#expr:250.8/.8/(60*1.852)round2}}|L/100 km|mpgus|abbr=on}}<ref name="747-8_perf">{{cite web |url= http://www.boeing.com/assets/pdf/commercial/startup/pdf/747-8_perf.pdf |title= 747-8 performance summary |publisher= Boeing |date= 2010 |deadurl= yes |archiveurl= https://web.archive.org/web/20140724231620/http://www.boeing.com/assets/pdf/commercial/startup/pdf/747-8_perf.pdf |archivedate= 2014-07-24 |df=  }}</ref>
 <!-- 250.8kg at .8kg/L for 6000nm * 1.852 nm per 100km -->
 |-
@@ Line 675: / Line 674: @@
 |}
-For comparison, a [[Volvo Buses|Volvo bus]] 9700 averages {{convert|{{#expr:26/63round2}}|L/100 km|mpgus}} per seat for 63 seats.<ref>{{cite web |url= http://volvobusenvironmentblog.com/2013/09/12/coach-fuel-consumption/ |title= Coach fuel consumption |date= 12 September 2013 |publisher= volvo buses |author= Edward Jobson}}</ref> In highway travel an average auto has the potential for {{convert|{{#expr:235.221/(36.5*4)round2}}|L/100 km|mpgus}}<ref>DEFRA (2008). [http://archive.defra.gov.uk/environment/business/reporting/pdf/passenger-transport.pdf 2008 Guidelines to Defra’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors]</ref> per seat (assuming 4 seats) and for a 5-seat 2014 [[Toyota Prius]], <!--1L/100km=235.221mpgus--> {{convert|{{#expr:235.221/(48*5)round2}}|L/100 km|mpgus}}.<ref>{{cite web |url= http://www.fueleconomy.gov/Feg/noframes/34489.shtml |title= 2014 Toyota Prius fuel economy |publisher= United States Environmental Protection Agency}}</ref> While this shows the capabilities of the vehicles, the load factors (percentage of seats occupied) may differ between personal use (commonly just the driver in the car) and societal averages for long-distance auto use, and among those of particular airlines.
+For comparison, a [[Volvo Buses|Volvo bus]] 9700 averages {{convert|{{#expr:26/63round2}}|L/100 km|mpgus}} per seat for 63 seats.<ref>{{cite web |url= http://volvobusenvironmentblog.com/2013/09/12/coach-fuel-consumption/ |title= Coach fuel consumption |date= 12 September 2013 |publisher= volvo buses |author= Edward Jobson}}</ref> In highway travel an average auto has the potential for {{convert|{{#expr:235.221/(36.5*4)round2}}|L/100 km|mpgus}}<ref>DEFRA (2008). [http://archive.defra.gov.uk/environment/business/reporting/pdf/passenger-transport.pdf 2008 Guidelines to Defra’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors] {{webarchive|url=https://web.archive.org/web/20120105065320/http://archive.defra.gov.uk/environment/business/reporting/pdf/passenger-transport.pdf |date=2012-01-05 }}</ref> per seat (assuming 4 seats) and for a 5-seat 2014 [[Toyota Prius]], <!--1L/100km=235.221mpgus--> {{convert|{{#expr:235.221/(48*5)round2}}|L/100 km|mpgus}}.<ref>{{cite web |url= http://www.fueleconomy.gov/Feg/noframes/34489.shtml |title= 2014 Toyota Prius fuel economy |publisher= United States Environmental Protection Agency}}</ref> While this shows the capabilities of the vehicles, the load factors (percentage of seats occupied) may differ between personal use (commonly just the driver in the car) and societal averages for long-distance auto use, and among those of particular airlines.
 ==== General aviation ====
@@ Line 685: / Line 684: @@
 [[File:X-48B from above.jpg|thumb|Boeing/NASA [[X-48B]] blended wing body demonstrator]]
-NASA and Boeing flight tested a {{convert|500|lb|abbr=on}} [[blended wing body]] (BWB) [[X-48B]] demonstrator from August 2012 to April 2013. This design provides greater fuel efficiency, since the whole craft produces lift, not just the wings.<ref>{{cite web |author=Hank Green |date=October 8, 2007 |url=http://www.ecogeek.org/content/view/871/ |publisher=Ecogeek |title=Fuel Efficient Plane Prototype Hits Skies |accessdate=July 6, 2014}}</ref> The BWB concept offers advantages in structural, aerodynamic and operating efficiencies over today's more conventional fuselage-and-wing designs. These features translate into greater range, fuel economy, reliability and life cycle savings, as well as lower manufacturing costs.<ref>{{cite press release |author=Tom Koehler |url=http://boeing.mediaroom.com/2006-10-27-Boeing-to-Begin-Ground-Testing-of-X-48B-Blended-Wing-Body-Concept |title=Boeing to Begin Ground Testing of X-48B Blended Wing Body Concept |publisher=Boeing |date=October 27, 2006 |accessdate=April 10, 2012}}</ref><ref>{{cite web |author= Philip Lorenz III |url= http://www.arnold.af.mil/news/story.asp?id=123059396 |title= AEDC testing brings unique blended wing aircraft closer to flight. |publisher= Arnold Air Force Base |date= July 3, 2007 |accessdate=April 10, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20140714223640/http://www.arnold.af.mil/news/story.asp?id=123059396 |archivedate=July 14, 2014 |df=mdy }}</ref> NASA has created a cruise efficient STOL (CESTOL) concept.
+NASA and Boeing flight tested a {{convert|500|lb|abbr=on}} [[blended wing body]] (BWB) [[X-48B]] demonstrator from August 2012 to April 2013. This design provides greater fuel efficiency, since the whole craft produces lift, not just the wings.<ref>{{cite web |author=Hank Green |date=October 8, 2007 |url=http://www.ecogeek.org/content/view/871/ |publisher=Ecogeek |title=Fuel Efficient Plane Prototype Hits Skies |accessdate=July 6, 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20140714133959/http://www.ecogeek.org/content/view/871/ |archivedate=July 14, 2014 |df= }}</ref> The BWB concept offers advantages in structural, aerodynamic and operating efficiencies over today's more conventional fuselage-and-wing designs. These features translate into greater range, fuel economy, reliability and life cycle savings, as well as lower manufacturing costs.<ref>{{cite press release |author=Tom Koehler |url=http://boeing.mediaroom.com/2006-10-27-Boeing-to-Begin-Ground-Testing-of-X-48B-Blended-Wing-Body-Concept |title=Boeing to Begin Ground Testing of X-48B Blended Wing Body Concept |publisher=Boeing |date=October 27, 2006 |accessdate=April 10, 2012}}</ref><ref>{{cite web |author= Philip Lorenz III |url= http://www.arnold.af.mil/news/story.asp?id=123059396 |title= AEDC testing brings unique blended wing aircraft closer to flight. |publisher= Arnold Air Force Base |date= July 3, 2007 |accessdate=April 10, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20140714223640/http://www.arnold.af.mil/news/story.asp?id=123059396 |archivedate=July 14, 2014 |df=mdy }}</ref> NASA has created a cruise efficient STOL (CESTOL) concept.
 Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research (IFAM) have researched a [[shark]] skin imitating paint that would reduce drag through a [[riblet effect]].<ref>{{cite web |last= Mahony |first= Melissa |url= http://www.smartplanet.com/blog/intelligent-energy/a-sharkskin-coating-for-ships-planes-and-blades/1289 |title= A sharkskin coating for ships, planes and blades |publisher= SmartPlanet |date= 2010-05-25 |accessdate=2012-09-29}}</ref> Aircraft is a major potential application for new technologies such as aluminium [[metal foam]] and [[nanotechnology]] such as the shark skin imitating paint.