Transportation Costs - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 247

Fig. 16.7 Phases of the
development of an airplane
prototype
personnel (19.8%), landing and navigation fees for the airport and air traffic
control which correspond directly to the weight (15.6%), the maintenance costs of
the aircraft (8.8%) and of the engine (2.7%), the amortization (16.7%), the
financing costs (7.0%), and the insurance costs (1.0%). The last three parameters
directly depend upon the airplane's price [ 28 ].
The DOC of a medium range, single-aisle airplane can be reduced up to 0.40%
by a 1% reduction in the SFC, up to 0.30% by 1% reduction in drag, up to 0.20%
by 1% reduction in weight, and up to 0.25% by 1% reduction in investigations
during development and production [ 29 ].
Experience shows that reducing the cockpit crew from 3 to 2 men saved
approximately 4% of the DOC. Further crew reductions are planned for freight
transportation. In civil aviation, two pilots will continue to remain in the cockpit in
the future.
Unmanned airplanes, so-called drones has become more important not only in
the military but also in the civil aviation for research, economy and ecology.
All new technologies in aviation aim to decrease the direct operating costs.
Using rebuilt or new jet engines with propfans is one of the best ways to decrease
SFC. A propfan is a modified turbofan engine with the fan placed outside the
engine nacelle and sitting on the same axle as the fan blades of a turbofan. It is also
known as Ultra High Bypass engine which requires an open rotor jet engine with
contra-rotating blades. The design is intended to offer the speed and the perfor-
mance of a turbofan, with the fuel economy of a turboprop [ 30 ].