PHAK 11: Aircraft Performance Flashcards
Introduction
What four factors affect aircraft performance?
- Aircraft weight
- Atmospheric conditions
- Runway environment
- Physical laws governing forces on an aircraft
Importance of Performance Data
Where can a pilot find operating data for an aircraft?
In the Aircraft Flight Manual/Pilot’s Operating Handbook (AFM/POH), under the performance or operational information section.
Importance of Performance Data
What types of data are included in the performance section of the AFM/POH?
Data on takeoff, climb, range, endurance, descent, and landing.
Importance of Performance Data
Why is understanding performance data essential?
For safe and efficient operation and to make practical use of the aircraft’s capabilities and limitations.
Importance of Performance Data
How is performance data commonly presented in the AFM/POH?
As tables, graphs, or both, and based on standard atmospheric conditions, pressure altitude, or density altitude.
Importance of Performance Data
What must a pilot do to use performance data effectively?
Recognize variations in presentation and make necessary adjustments based on atmospheric conditions.
Importance of Performance Data
What atmospheric factors have a major effect on aircraft performance?
Pressure and temperature.
Structure of the Atmosphere
What is the atmosphere?
An envelope of air that surrounds the Earth, composed of a mixture of gases with mass, weight, and indefinite shape.
Structure of the Atmosphere
What percentage of the atmosphere is nitrogen?
78%.
Structure of the Atmosphere
What percentage of the atmosphere is oxygen?
21%.
Structure of the Atmosphere
What percentage of the atmosphere is composed of other gases?
1% (e.g., argon, helium).
Structure of the Atmosphere
Where is most of the atmosphere’s oxygen concentrated?
Below 35,000 feet altitude.
Structure of the Atmosphere
How does air behave as a fluid?
It flows, changes shape under pressure, and expands or contracts to fill its container.
Atmospheric Pressure
What is atmospheric pressure?
The force exerted by the weight of the atmosphere in all directions.
Atmospheric Pressure
Name four flight instruments actuated by atmospheric pressure.
- Altimeter
- Airspeed Indicator (ASI)
- Vertical Speed Indicator (VSI)
- Manifold Pressure Gauge
Atmospheric Pressure
What is the average atmospheric pressure at sea level under standard conditions?
14.7 pounds per square inch (psi).
Atmospheric Pressure
How does reduced air density affect aircraft performance?
It reduces power, thrust, and lift.
Atmospheric Pressure
What are the standard atmosphere conditions at sea level?
- 59°F @ 29.92 inches of mercury (“Hg)
- 15°C @ 1013.2 millibars (mb)
Atmospheric Pressure
What is the standard temperature lapse rate?
Temperature decreases 3.5°F (2°C) per 1,000 feet up to 36,000 feet.
Atmospheric Pressure
What is the standard pressure lapse rate?
Pressure decreases 1 inch of mercury (“Hg) per 1,000 feet of altitude gain to 10,000 feet.
Atmospheric Pressure
What is the International Standard Atmosphere (ISA)?
A worldwide standard established by the International Civil Aviation Organization (ICAO) with specific lapse rates for temperature and pressure.
Atmospheric Pressure
What are nonstandard temperature and pressure?
Conditions where atmospheric temperature or pressure differ from the standard lapse rates.
Atmospheric Pressure
Why are corrections needed for nonstandard atmospheric conditions?
Because aircraft instruments and performance are calibrated for standard atmospheric conditions.
Pressure Altitude
What is pressure altitude?
The height above the standard datum plane (SDP), where atmospheric pressure is 29.92 “Hg.