Chapter 6 - Altimetry Flashcards
What is regional QNH or regional pressure setting (RPS)?
The lowest forecast QNH in a region, valid for an hour.
Used for cross country flights at relatively low level.
If a plane is travelling from high to low pressure will the altimeter over read or under read?
It will over read. It will think the aircraft is higher than it actually is!
“High to low, look out below!”
What is meant by “transition altitude”?
It is the altitude at which an aircraft should switch from QNH to SPS.
It is a fixed altitude and is set to make sure terrain can be avoided before switching to SPS.
What is meant by “transition level”?
It is the lowest flight level available.
It guarantees 500ft separation vertically from an aircraft flying on QNH.
It is not a fixed altitude and varies based on transition altitude.
When will ATC specify transition level as a cruising FL?
ATC will never issue it as a flight level. the lowest cruising flight level will be 500ft above transition level.
What is meant by “transition layer”?
The space between Transition level and transition altitude.
How do you apply a temperature correction to an indicated altitude?
Temperature correction = 4 x ISA Deviation x thousands of feet
Define Altitude.
Vertical distance above MSL
Define Height.
Vertical distance above a specified datum.
Define elevation
Altitude of a fixed object. Eg. an airfield.
Define a flight level.
Indicated altitude with SPS set.
Define density altitude.
True altitude. Indicated altitude corrected for temperature error.
Define temperature error for altimeters.
The difference between Baro corrected indicated altitude and true altitude.
What is the process of going from indicated altitude to true altitude?
1) Indicated altitude
2) Baro/pressure correction
3) Temperature correction
4) True altitude
And reverse is true but temp correction must be applied backwards.
