Effects of Field Elevation, Temperature, and Humidity
Field elevations and runway temperatures are vital elements in the control of jet aircraft.
An example of the effect that altitude has on a light aircraft is that an aircraft with a rate
of climb of 420 feet per minute (fpm) at sea level has its rate of climb reduced to 225
fpm at 5,000 feet (ft). The distance needed for takeoff is doubled between these two
altitudes (see Figure 3-2.)
Figure 3-2 -- Comparison of takeoff distances with increased altitudes.
High temperatures and high humidity have similar effects on aircraft performance. A
high-performance jet fighter may not be able to operate from an airfield with short
runways on a day in which high runway temperatures prevail, even if the field elevation
is only moderately high. Later in the afternoon or at night, the same fighter may be able
to affect a takeoff from the same field because the atmosphere cools and becomes
denser during night hours. More lift is afforded an aircraft in dense air, regardless of
aircraft type.
Aircraft Speeds
One great concern in air traffic control is aircraft speed. While speeds of conventional-
type aircraft vary, speed differences between conventional and jet aircraft are even
greater. You need to be aware of these differences and take them into consideration.
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