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What is the relationship, if any, between QFE and QNH at an airport situated 50 ft below sea level?
• A
No clear relationship exists.
• B
QFE is greater than QNH.
• C
QFE equals QNH.
• D
QFE is smaller than QNH.

QNH = The atmospheric pressure adjusted to mean sea-level.
If you are on the ground at an airport and turn in the local QNH at your altimeter’s subscale, it will display the airports altitude above mean sea level.

QFE = The pressure set on the altimeter so that it indicates the height above the reference elevation being used (height above current ground level).
If you set the QFE on your altimeter’s subscale on the ground, the altimeter would read 0 feet.
So, it is used to get to know the height above the ground.

QNE = The indicated altitude at the landing runway threshold when 1013,25 is set in the altimeter’s subscale. In other words, it is the pressure altitude at the landing runway threshold.

QFF = Mean sea level pressure, derived by taking into account the actual temperature conditions. So, the QFE reduced to mean sea level with regard to the actual outside air temperature.

In the case of this specific question: The question asks about the QFE and QNH at an airport situated 50 feet below sea level.
Because of this the QFE will be measured 50 feet below sea level, the QNH will still be measured at sea level which is 50 feet higher.
We know that a higher altitude has a lower pressure, so the barometric value of QNH is lower than QFE.
We can say that QNH is always greater or equal to QFE except when the airport is situated under sea level.

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