Performance And Limitations (Cml)

Front 1

What are standard atmosphere temperature and pressure lapse rates?

Back 1

A standard temperature lapse rate is one in which the temperature decreases at the rate of approximately 3.5°F or 2°C per 1,000 feet up to 36,000 feet. Above this point, the temperature is considered constant up to 80,000 feet. A standard pressure lapse rate is one in which pressure decreases at a rate of approximately 1 "Hg per 1,000 feet of altitude gain to 10,000 feet.

Front 2

What effect does atmospheric pressure have on air density?

Back 2

Air density is directly proportional to pressure. If the pressure is doubled, the density is doubled, and if the pressure is lowered, so is the density. This statement is true only at a constant temperature.

Front 3

What effect does humidity have on air density?

Back 3

Water vapor is lighter than air, so moist air is lighter than dry air. As the water content of the air increases, the air becomes less dense, increasing density altitude and decreasing performance. It is lightest or least dense when it contains the maximum amount of water vapor. Humidity alone is usually not considered an important factor in calculating density altitude and airplane performance, but it does contribute.

Front 4

What is the definition of relative humidity?

Back 4

Relative humidity refers to the amount of water vapor in the atmosphere, and is expressed as a percentage of the maximum amount of water vapor the air can hold. This amount varies with the temperature-~-warm air can hold more water vapor and colder air can hold less.

Front 5

What are the two types of drag?

Back 5

Total drag can be divided into two parts; the wing drag (induced), and everything but the wing drag (parasite)

Front 6

Define induced drag.

Back 6

Induced drag is the part of total drag created by the production of lift. Induced drag increases with a decrease in airspeed. The lower the airspeed, the greater the angle of attack required to produce lift equal to the airplane's weight, and therefore the greater the induced drag.

Front 7

Define parasite drag.

Back 7

Parasite drag is drag caused by the friction of air moving over the aircraft structure; its amount varies directly with the airspeed. It is the drag that is not associated with the production of lift and includes the displacement of the air by the aircraft, turbulence generated in the airstream, or a hindrance of air moving over the surface of the aircraft and airfoil. There are three types of parasite drag: form drag, interference drag, and skin friction drag.

Front 8

How much will drag increase as airplane speed increases?

Back 8

If an airplane in a steady flight condition at 100 knots is then accelerated to 200 knots, the parasite drag becomes four times as great, but the power required to overcome that drag is eight times the original value. Conversely, when the airplane is operated in steady, level flight at twice as great a speed, the induced drag is one-fourth the original value, and the power required to overcome that drag is only one-half the original value.

Front 9

Climb performance is a result of using the aircraft's potential energy provided by one, or a combination of two, factors. What are those two factors?

Back 9

a. Use of excess power above that required for level flight. An aircraft equipped with an engine capable of 200 horsepower (at a given altitude) but using 130 horsepower to sustain level flight (at a given airspeed) has 70 excess horsepower available for climbing.

b. Use of the aircraft's kinetic energy. An aircraft can trade off its kinetic energy and increase its potential energy by reducing its airspeed. The reduction in airspeed will increase the aircraft's potential energy, making the aircraft climb.

Front 10

What is the definition of absolute ceiling?

Back 10

Absolute ceiling is the altitude at which a climb is no longer possible.

Front 11

What is meant by the terms power loading and wing loading?

Back 11

Power loading- expressed in pounds per horsepower and is obtained by dividing the total weight of the airplane by the rated horsepower of the engine. It is a significant factor in the airplane's takeoff and climb capabilities.

Wing loading- expressed in pounds per square foot and is obtained by dividing the total weight of the airplane in pounds by the wing area (including ailerons) in square feet. It is the airplane's wing loading that determines the landing speed.

Front 12

What is ground effect?

Back 12

Ground effect occurs due to the interference of the ground surface with the flow pattern about the airplane in flight, when the airplane is flown at approximately one wingspan above the surface. Especially with low-wing aircraft, it is most significant when the airplane is maintaining a constant attitude at low airspeed and low altitude. For example: during landing flare before touchdown, and during takeoff when the airplane lifts off and accelerates to climb speed. A wing in ground effect has a reduction in upwash, downwash, and tip vortices. With reduced tip vortices, induced drag is reduced. When the wing is at a height equal to one-fourth the span, the reduction in induced drag is about 25 percent, and when the wing is at a height equal to one-tenth the span, this reduction is about 50 percent.

Front 13

What is flight in the region of normal command?

Back 13

It means that while holding a constant altitude, a higher airspeed requires a higher power setting, and a lower airspeed requires a lower power setting. The majority of all airplane flying (climb, cruise, and maneuvers) is conducted in the region of normal command.

Front 14

What is flight in the region of reversed command?

Back 14

It means that a higher airspeed requires a lower power setting, and a lower airspeed requires a higher power setting to hold altitude. It does not imply that a decrease in power will produce lower airspeed. The region of reversed command is encountered in the low-speed phases of flight. Flight speeds below the speed for maximum endurance (lowest point on the power curve) require higher power settings with a decrease in airspeed. Because the need to increase the required power setting with decreased speed is contrary to the "normal command" of flight, flight speeds between minimum required power setting (speed) and the stall speed (or minimum control speed) is termed the region of reversed command. In the region of reversed command, a decrease in airspeed must be accompanied by an increased power setting in order to maintain steady flight.

Front 15

Why does the manufacturer provide various manifold pressure/prop settings for a given power output?

Back 15

The various power MAP/rpm combinations are provided so the pilot has a choice between operating the aircraft at best efficiency (minimum fuel flow) or operating at best power/speed condition. An aircraft engine operated at higher rpms will produce more friction and, as a result, use more fuel. On the other hand, an aircraft operating at higher and higher altitudes will not be able to continue to produce the same constant power output due to a drop in manifold pressure. The only way to compensate for this is by operating the engine at a higher rpm.

Front 16

What does the term 75 percent brake horsepower mean?

Back 16

Brake horsepower (BHP) is the power delivered at the propeller shaft (main drive or main output) of an aircraft engine. 75 percent BHP means you are delivering 75 percent of the normally rated power or maximum continuous power available at sea level on a standard day to the propeller shaft.

Front 17

What effect does a forward center of gravity have on an aircraft's flight characteristics?

Back 17

Higher stall speed--Stalling angle of attack reached at a higher speed due to increased wing loading.

Slower cruise speed--Increased drag, greater angle of attack required to maintain altitude.

More stable--The center of gravity is further forward from the center of pressure, which increases longitudinal stability.

Greater back elevator pressure required--Longer takeoff roll, higher approach speeds and problems with the landing flare.

Front 18

What effect does an aft center of gravity have on an aircraft' flight characteristics?

Back 18

Lower stall speed- Less wing loading.

Higher cruise speed-_-Reduced drag, smaller angle of attack required to maintain altitude.

Less stable- Stall and spin recovery more difficult; when angle of attack is increased it tends to result in additional increased angle of attack.

Front 19

Will the center of gravity be forward or aft of the center of pressure?

Back 19

Forward. The designers determine how far the center of pressure (CP) will travel. It is important to understand that an aircraft's weight is concentrated at the CG and the aerodynamic forces of lift occur at the CP. When the CG is forward of the CP, there is a natural tendency for the aircraft to want to pitch nose down. If the CP is forward of the CG, a nose up pitching moment is created. Therefore, designers fix the aft limit of the CG forward of the CP for the corresponding flight speed in order to retain flight equilibrium.

Front 20

Explain the term percent of mean aerodynamic chord (MAC).

Back 20

Expression of the CG relative to the MAC is a common practice in larger aircraft. The CG position is expressed as a percent MAC (percent of mean aerodynamic chord), and the CG limits are expressed in the same manner. Normally, an aircraft will have acceptable flight characteristics if the CG is located somewhere near the 25 percent average chord point. This means the CG is located one-fourth of the total distance back from the leading edge of the average wing section.

Front 21

How is the CG affected during flight as fuel is used?

Back 21

As fuel is burned during flight, the weight of the fuel tanks will change and as a result the CG will change. Most aircraft, however, are designed with the fuel tanks positioned close to the CG; therefore, the consumption of fuel does not affect the CG to any great extent. Also, the lateral balance can be upset by uneven fuel loading or burn-off. The position of the lateral CG is not normally computed for an airplane, but the pilot must be aware of the adverse effects that will result from a laterally unbalanced condition.

Front 22

What is the wing loading for a 172N?

Back 22

13.2 lbs/ sq ft

Front 23

What is the wing loading for a 172N?

Back 23

13.2 lbs/ sq ft

Front 24

What is the power loading for a 172N?

Back 24

14.4 lbs/ HP

Front 25

What is the generic takeoff performance to clear a 50’ obstacle?

Back 25

1440’

Front 26

What is the generic takeoff performance to clear a 50’ obstacle?

Back 26

1440’

Front 27

What is the generic landing performance of a 172N to clear a 50’ obstacle?

Back 27

1250’

Front 28

What is the CARE checklist?

Back 28

Consequences

Alternatives

Reality

External Factors

Front 29

What is the CARE checklist?

Back 29

Consequences

Alternatives

Reality

External Factors

Front 30

What is the TEAM checklist?

Back 30

Transfer

Eliminate

Accept

Mitigate

Front 31

When must a plane have an operative Anticollision light SYSTEM for day VFR?

Back 31

If certificated after March 11, 1996