Aircraft Performance

Angle of Climb (AOC)

obtained at VX, may provide climb performance to ensure an aircraft will clear obstacles.

Maximum Rate of Climb (ROC)

obtained at VY, provides climb performance to achieve the greatest altitude gain over time.

higher, lower

A decrease in air density means a ______ density altitude; an increase in air density means a _____ density altitude.

increases

As the density of the air increases (lower density altitude), aircraft performance

Pressure altitude

If the altimeter is set for 29.92 "Hg SDP, the altitude indicated is the

decreases, increases

Increasing the temperature of a substance __________ its density. Conversely, decreasing the temperature __________ the density.

altimeter, the airspeed indicator (ASI), the vertical speed indicator (VSI), and the manifold pressure gauge.

It is one of the basic factors in weather changes, helps to lift the aircraft, and actuates some of the most important flight instruments in the aircraft. These instruments often include the

Kinetic Energy (KE), Potential Energy (PE)

Mechanical energy comes in two forms:

Potential Energy (PE)

Positive climb performance occurs when an aircraft gains ______ by increasing altitude.

high elevations, low atmospheric pressures, high temperatures, high humidity, or some combination of these factors.

The conditions that result in a high density altitude are

Lower elevations, high atmospheric pressure, low temperatures, and low humidity

The conditions that result in a low density altitude are

standard temperature 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.

Power because the engine takes in less air Thrust because the propeller is less efficient in thin air Lift because the thin air exerts less force on the airfoils

The density of air has significant effects on the aircraft's performance. As air becomes less dense, it reduces:

14.7

Under standard conditions at sea level, the average pressure exerted by the weight of the atmosphere is approximately

less, decreasing

Water vapor is lighter than air; consequently, moist air is lighter than dry air. Therefore, as the water content of the air increases, the air becomes ______ dense, increasing density altitude and ________ performance.

high, low

______ density altitude refers to thin air while ____ density altitude refers to dense air.

standard temperature lapse rate

is one in which the temperature decreases at the rate of approximately 3.5 °F or 2 °C per thousand feet up to 36,000 feet.

Density altitude

is pressure altitude corrected for nonstandard temperature.

Pressure altitude

is the height above the standard datum plane (SDP).

Humidity

also called relative humidity, refers to the amount of water vapor contained in the atmosphere and is expressed as a percentage of the maximum amount of water vapor the air can hold.

atmosphere

an envelope of air that surrounds the Earth and rests upon its surface. It is as much a part of the Earth as is land and water. However, air differs from land and water in that it is a mixture of gases. It has mass, weight, and indefinite shape.

decreases

as air density decreases (higher density altitude), aircraft performance

Aircraft Flight Manual/Pilot's Operating Handbook (AFM/ POH)

contains the operating data for the aircraft; that is, the data pertaining to takeoff, climb, range, endurance, descent, and landing.

59, 15, 29.92, 1013.2

has a surface temperature of____ degrees Fahrenheit (°F) or ____ degrees Celsius (°C) and a surface pressure of _____ inches of mercury ("Hg) or _______ millibars (mb).

The International Civil Aviation Organization (ICAO)

has established this as a worldwide standard, and it is often referred to as International Standard Atmosphere (ISA) or ICAO Standard Atmosphere.

standard datum plane (SDP)

is a theoretical level at which the pressure of the 30.5 atmosphere is 29.92 "Hg and the weight of air is 14.7 psi

Air density

is affected by changes in altitude, temperature, and humidity

Calibrated airspeed (CAS)

the ASI reading corrected for position (or installation) and instrument errors.

Equivalent airspeed (EAS)

the ASI reading corrected for position (or installation), for instrument error, and for adiabatic compressible flow for the particular altitude. (EAS is equal to CAS at sea level in standard atmosphere.)

V A

the calibrated design maneuvering airspeed. This is the maximum speed at which the limit load can be imposed (either by gusts or full deflection of the control surfaces) without causing structural damage.

V S1

the calibrated poweroff stalling speed or the minimum steady flight speed at which the aircraft is controllable in a specified configuration.

V S0

the calibrated poweroff stalling speed or the minimum steady flight speed at which the aircraft is controllable in the landing configuration.

Kinetic Energy (KE)

the energy of speed

V FE

the highest speed permissible with the wing flaps in a prescribed extended position. This is because of the air loads imposed on the structure of the flaps.

V LE

the maximum speed at which the aircraft can be safely flown with the landing gear extended. This is a problem involving stability and controllability.

V LO

the maximum speed at which the landing gear can be safely extended or retracted. This is a problem involving the air loads imposed on the operating mechanism during extension or retraction of the gear.

V N0

the maximum speed for normal operation or the maximum structural cruising speed. This is the speed at which exceeding the limit load factor may cause permanent deformation of the aircraft structure.

VX

the speed at which the aircraft obtains the highest altitude in a given horizontal distance.

VY

the speed at which the aircraft obtains the maximum increase in altitude per unit of time. This best ROC speed normally decreases slightly with altitude.

Indicated airspeed (IAS)

the speed of the aircraft as observed on the ASI. It is the airspeed without correction for indicator, position (or installation), or compressibility errors.

True airspeed (TAS)

the speed of the aircraft in relation to the air mass in which it is flying.

V NE

the speed that should never be exceeded. If flight is attempted above this speed, structural damage or structural failure may result.

Potential Energy (PE)

the stored energy of position.