Page 97 - Planning and Design of Airports

Air craft Characteristics Related to Airport Design 67

Specific Fuel
Aircraft Engine Bypass Radio Consumption *
A340 CFM56-5C2 6.4 0.32
B-757 PW2037 6.0 0.33
A-330-300 CF6-80E1A2 5.1 0.33
A320 CFM56-5A1 6.0 0.33
B737-400/500 CFM56-3Ca 6.0 0.33
A-310 PW4152 4.9 0.348
B-767-200 CF6-80A2 4.7 0.35
B-747-400 PW4056 4.9 0.359
B-737-600 CFM56-7B20 5.5 0.36
A-321-200 V2533-A5 4.6 0.37
BA-146-300 LF507 5.6 0.406
MD-80 JT8D-219 1.8 0.519

∗ Specific Fuel Consumption is the amount of fuel required, in pounds, to create
1 lb of thrust.

TABLE 2-5 Performance Characteristics of Typical Jet Aircraft Engines

hour per pound of thrust. Fuel consumption of jet aircraft engines
tends to be expressed in pounds rather than in gallons. This is because
the volumetric expansion and contraction of fuel with changes in
temperature can be misleading in the amount of fuel which is avail-
able. Each gallon of jet fuel weighs about 6.7 lb.
Specific fuel consumption for a particular type of aircraft, defined as
the amount of fuel required (in pounds) to create 1 lb of thrust, is a
function of its weight, altitude, and speed. Some typical values are
given in Table 2-5 merely to illustrate the fuel economy of a turbofan
engine particularly at high bypass ratios (a jet engine’s bypass ratio is
defined as the ratio between the mass flow rate of air drawn in by the
fan but bypassing the engine core to the mass flow rate passing
through the engine core). Significant gains in specific fuel consump-
tion have been made with modern aircraft. Table 2-6 gives the approx-
imate average consumption of fuel for typical aircraft.
Fuel consumption improvements in the last two decades have
been significant. New engines, such as the CFM56, CF6, RB211-524D,
and PW4000, as well as derivatives of current engines, have resulted
in significant fuel economy gains.
An indication of the differences in fuel consumption attained by
the various types of passenger aircraft in the different trip modes is
given in Table 2-5. It should be pointed out, however, that the data are
only indicators of fuel consumption and not productivity. Those air-
craft which burn the higher rates of fuel generally are capable of
greater speeds and have greater passenger capacity.