QNH

Understanding QNH – A Guide to Its Meaning and Significance in Aeronautics

QNH is a Q code utilized within the realm of aeronautics. It refers to the barometric altimeter setting, which is necessary for measuring airfield elevation above the mean sea level. Pilots must use the QNH when they require accurate altitude measurements.

The standard QNH that pilots use when flying at flight levels is set at 1013.25 hPa / 29.92 inHg. This setting acts as a reference point for pilots to adjust their altimeters based on the surrounding atmospheric pressure.

The use of QNH is crucial to aviation safety, as it ensures pilots are aware of their precise altitude and distance from the ground, preventing collisions with any obstacles on their flight path. Pilots must carefully monitor weather and other atmospheric changes that can affect QNH measurements and, in turn, their altitude measurements.

In summary, QNH is a vital component in keeping pilots informed of their altitude and providing them with critical information to avoid colliding with obstacles and other aircraft in the sky.