Altimeter Flashcards
(16 cards)
What is the pressure source for the altimeter?
Static only
What are the 3 types of altimeter?
- Simple altimeter
- Sensitive altimeter
- Servo altimeter
What does a servo altimeter use?
E and I bar on a pivot
Why don’t we use GPS derived altitude?
Does not provide the same relative separation fro other aircraft
What ensures the integrity of GPS data?
RAIM (receiver autonomous integrity monitoring)
What are the errors for a altimeter?
- IMP
- Temperature
- Barometric
- Time lag
What is temperature error?
The altimeter is calibrated against ISA atmosphere, if conditions are different displayed values will not indicate true altitude
What happens when you fly from high temp to low temp?
The altimeter over reads, the aircraft is lower than indicated
What happens when flying from warm/high to cold/low?
True altitude decreases, altimeter over reads
High to low look out below
How can temperature error be corrected?
Applying a temperature error correction
Height/1000 x 4 x ISA dev
What is barometric error?
Flying from high to low pressure the altimeter will over read, high to low look out below
What is time lag error?
The amount of time it takes for a change in pressure to be sensed and converted into a mechanical movement, impact reduced by E and I bar
What happens if there is a static line blockage?
Frozen display
What happens if the static line has a leak in a pressurised aircraft inside the pressure hull?
Higher pressure will enter the line, this will cause the altimeter to under read
What happens if the static line has a leak in a pressurised aircraft outside the pressure hull?
Altimeter will still work but slightly less accurately, slight over read
What happens if there is a static leak in an unpressurised aircraft?
Lower pressure inside the cabin will suck out air from the altimeter and cause it to over read ‘cabin suction’
