Met/instruments Flashcards
What is pressure alt?
ISA height above the 1013 datum.
What is barometric pressure error?
Effect of flying in an area with different sea level pressure.
What is density?
Mass per unit volume
What are the main influences on air density?
- Temp
- Pressure
- Humidity
What pressure is used to calculate airspeed?
Dynamic pressure
Describe TAS
TAS is the actual speed of an ac through the air mass it is flying in.
What effects TAS?
Air density. The higher the air density, the lower the TAS
How does temp effect the local speed of sound (LSS)?
As temp decreases, the LSS decreases
How do you calculate Mach no.?
TAS/LSS
What happens to your Mach no. if you climb at a constant CAS or IAS?
Mach no will increase
If 2 ac are flying at diff levels at the same Mach no which ac has the higher TAS?
The lower ac as temperature will be higher
What does a pitot tube measure?
Total pressure
How do the instruments produce dynamic pressure?
Dynamics pressure = total pressure - static pressure
What pressure does an ASI use?
Dynamic pressure
What are the two gyroscopic properties?
- Rigidity
2. Precession
What does the rigidity property allow?
The gyro to remain stable in space while the ac moves around it
What will a change in direction or alt do to the gyro?
Precess the gyro
What is the error in gyros?
Wander
What is true heading a product of?
True hdg = mag hdg + Easterly variation.
What is a fail passive AL system?
In the event of a single control Chanel failure, there is no significant out of trim condition or deviation from the flight path or attitude
What is a fail operational system
3 computers. In the event of single failure, the remaining computers will continued to provide the capability to land
What does an anti skid system protect against?
- Locked wheel
- Wheel skid/slip
- Aqua planing
- Touchdown - locked wheels on landing
How is cabin press controlled?
With the outflow valves
What is the greatest contaminant of fuel?
Water
What steps can be taken against fuel contamination?
- Water drains in the fuel tanks
- Fuel heaters
- Atmospheric exclusion in the fuel tanks
What do fuel heaters do?
Evaporate water prior to delivery to the engine
Why is fuel not measured in terms of volume?
Volume changes with temp.
