1fa. Density Altitude and Aircraft PerformanceIn June, 2013,
temperatures at Sky Harbor Airport in Phoenix, Arizona, edged toward the
record high of 122 °F set in 1990. The 2013 heat wave peaked at 119 °F
and did not break the record, but when the temperature reached 118 °F,
some flights were canceled. Why? High temperatures can affect aircraft
performance. As temperature rises, air becomes less dense, with fewer
air molecules per unit of volume, and therefore provides less lift.
Under hot conditions, planes require longer runways for takeoffs and
landings, and pilots must fly the plane in a way that compensates for
reduced lift. Failure to make these adjustments could result in an
accident.The relationship between air pressure, temperature, and
altitude is key to understanding the effects of high temperature on
aircraft performance.7 Recall that air pressure always decreases with
altitude. However, at higher temperatures, the air is less dense and air
pressure is lower than it would otherwise be at a given altitude. In
aviation, this relationship is expressed as density altitude, shown in
Figure 9-5-1. As you can see from the chart, the higher the temperature,
the higher the density altitude. For example, an airport that is 2,000
feet above mean sea level and 100 °F would have a density altitude of
5000 feet.How do pilots correct aircraft performance for the effects of
an airports increased density altitude? Aircraft manufacturers often
provide a manual containing aircraft performance charts for density
altitude. Based on these charts, the pilot can determine how much
additional runway will be needed for takeoff, how much the rate of climb
will be reduced, and how much air speed should be increased. The pilot
may decide to reduce the aircraft's weight before takeoff by carrying
less cargo or fuel. The Koch Chart in Figure 9-5-2 provides a quick
estimate of how temperature affects takeoff distance and rate of climb.
To use it, draw a straight line between the expected temperature on the
left axis and the airport altitude on the right axis, and then observe
the information at the point of intersection on the inset.Airlines may
schedule flights so as to reduce aircraft exposure to high density
altitude, For example, a flight heading to Phoenix in the summer could
get priority for takeoff out of New York, so they can arrive before the
hottest part of the day. Even then, the plane will need to be prepared
for landing at a higher speed.FIGURE 9-5-1 Density Altitude and
Temperature....FIGURE 9-5-2 Koch Chart. The blue line shows an example
in which the expected airport temperature is 110 °F and the airport
elevation is 6,000 feet...What are the factors that determine the
density altitude of an airport? Get solution
2fa. Density Altitude and Aircraft PerformanceIn June, 2013, temperatures at Sky Harbor Airport in Phoenix, Arizona, edged toward the record high of 122 °F set in 1990. The 2013 heat wave peaked at 119 °F and did not break the record, but when the temperature reached 118 °F, some flights were canceled. Why? High temperatures can affect aircraft performance. As temperature rises, air becomes less dense, with fewer air molecules per unit of volume, and therefore provides less lift. Under hot conditions, planes require longer runways for takeoffs and landings, and pilots must fly the plane in a way that compensates for reduced lift. Failure to make these adjustments could result in an accident.The relationship between air pressure, temperature, and altitude is key to understanding the effects of high temperature on aircraft performance.7 Recall that air pressure always decreases with altitude. However, at higher temperatures, the air is less dense and air pressure is lower than it would otherwise be at a given altitude. In aviation, this relationship is expressed as density altitude, shown in Figure 9-5-1. As you can see from the chart, the higher the temperature, the higher the density altitude. For example, an airport that is 2,000 feet above mean sea level and 100 °F would have a density altitude of 5000 feet.How do pilots correct aircraft performance for the effects of an airports increased density altitude? Aircraft manufacturers often provide a manual containing aircraft performance charts for density altitude. Based on these charts, the pilot can determine how much additional runway will be needed for takeoff, how much the rate of climb will be reduced, and how much air speed should be increased. The pilot may decide to reduce the aircraft's weight before takeoff by carrying less cargo or fuel. The Koch Chart in Figure 9-5-2 provides a quick estimate of how temperature affects takeoff distance and rate of climb. To use it, draw a straight line between the expected temperature on the left axis and the airport altitude on the right axis, and then observe the information at the point of intersection on the inset.Airlines may schedule flights so as to reduce aircraft exposure to high density altitude, For example, a flight heading to Phoenix in the summer could get priority for takeoff out of New York, so they can arrive before the hottest part of the day. Even then, the plane will need to be prepared for landing at a higher speed.FIGURE 9-5-1 Density Altitude and Temperature....FIGURE 9-5-2 Koch Chart. The blue line shows an example in which the expected airport temperature is 110 °F and the airport elevation is 6,000 feet...Summarize how a pilot can compensate for the effects of density altitude on aircraft performance. Would it be a good idea to rely solely on the Koch chart? Explain. Get solution
2fa. Density Altitude and Aircraft PerformanceIn June, 2013, temperatures at Sky Harbor Airport in Phoenix, Arizona, edged toward the record high of 122 °F set in 1990. The 2013 heat wave peaked at 119 °F and did not break the record, but when the temperature reached 118 °F, some flights were canceled. Why? High temperatures can affect aircraft performance. As temperature rises, air becomes less dense, with fewer air molecules per unit of volume, and therefore provides less lift. Under hot conditions, planes require longer runways for takeoffs and landings, and pilots must fly the plane in a way that compensates for reduced lift. Failure to make these adjustments could result in an accident.The relationship between air pressure, temperature, and altitude is key to understanding the effects of high temperature on aircraft performance.7 Recall that air pressure always decreases with altitude. However, at higher temperatures, the air is less dense and air pressure is lower than it would otherwise be at a given altitude. In aviation, this relationship is expressed as density altitude, shown in Figure 9-5-1. As you can see from the chart, the higher the temperature, the higher the density altitude. For example, an airport that is 2,000 feet above mean sea level and 100 °F would have a density altitude of 5000 feet.How do pilots correct aircraft performance for the effects of an airports increased density altitude? Aircraft manufacturers often provide a manual containing aircraft performance charts for density altitude. Based on these charts, the pilot can determine how much additional runway will be needed for takeoff, how much the rate of climb will be reduced, and how much air speed should be increased. The pilot may decide to reduce the aircraft's weight before takeoff by carrying less cargo or fuel. The Koch Chart in Figure 9-5-2 provides a quick estimate of how temperature affects takeoff distance and rate of climb. To use it, draw a straight line between the expected temperature on the left axis and the airport altitude on the right axis, and then observe the information at the point of intersection on the inset.Airlines may schedule flights so as to reduce aircraft exposure to high density altitude, For example, a flight heading to Phoenix in the summer could get priority for takeoff out of New York, so they can arrive before the hottest part of the day. Even then, the plane will need to be prepared for landing at a higher speed.FIGURE 9-5-1 Density Altitude and Temperature....FIGURE 9-5-2 Koch Chart. The blue line shows an example in which the expected airport temperature is 110 °F and the airport elevation is 6,000 feet...Summarize how a pilot can compensate for the effects of density altitude on aircraft performance. Would it be a good idea to rely solely on the Koch chart? Explain. Get solution
