Level 3 Aviation test Flashcards
What is stability
It’s the tendancy of an aircraft during flight to remain straight and level and to return to this altitude, if displaced.
What is static stability?
The initial tendency of an aircraft when disturbed, to return to the original position
What is dynamic stability?
Overall tendency of an airplane to return to its original position following a series of damped out oscillations
What is positive stability?
The aircraft develops forces or moments which tend to restore it to its original position
What is neutral stability
There are no restoring forces and the airplane will neither return from its disturbed position nor move further
What is negative stability
Develop forces or moments to move further away. It is also called instability.
What is longitudinal stability?
Stability around the lateral axis also known as pitch stability.
How do you obtain longitudinal stability?
Airplanes are designed to be nose heavy when correctly loaded. The centre of gravity is ahead of the centre of pressure.
What does the airplane need if the plane is nose heavy?
A tailplane
What are the two factors that effect longitudinal stability
- Size and position of the horizontal stabilizer
2. Position of the centre of gravity
What is lateral stability
Stability around the longitudinal axis also called roll stability
What is lateral stability achieved through (4)
- Dihedral
- Sweepback
- Keel effect
- Proper distribution of weight
What is directional stability and is the most important feature?
Stability around the vertical axis and the fin and rudder are most important
What is this atmosphere made up of?
78% nitrogen
21% oxygen
Rest are other gases(argon, carbon dioxide, water vapour)
What are the principal properties of the atmosphere?
Mobility
Capacity for expansion
Capacity for compression
What are the four layers of the atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere
How tall is the troposphere
28 000 ft above sea level at the poles to 54 000 ft at the equator
What happens in the troposphere
The most weather occurs and the lowest temperature is -56 degrees Celsius
Where is the stratosphere located
50 000 ft above the tropopause
What happens as you move up the layers
Pressure decreases and temperature increases to 0 degrees Celsius
What later exists in the stratosphere
Ozone
What happens in the mesosphere
Meteorites burn up
What is the temperature like in the mesosphere?
-100 degrees Celsius at 275 000 ft above earth’s surface
What are the conditions of the ICAO
- Air is dry gas
- A mean sea level pressure of 29.92 inches of mercury
- A mean sea level temperature of 15 degrees Celsius
- The rate of decrease temperature with altitude is 1.98 degrees Celsius per 1000 ft
