[Guest]

Mainly seen in the FMC options.

Thanks!

[AS380 Mark Richards]

QNH is the area or airport altimeter setting below the transition level obtained from the METAR or ATIS.

[as176andre]

Here are a few interesting bits:

QNH = is the pressure correction factor which causes the Altimeter to read the altitude above mean sea level (Plus the height of the Altimeter above the ground). It is sometimes referred to as the barometric pressure at an airfield, reduced to mean sea level.

QFE = Is the barometric pressure at an airfield. When this is set on the subscale of an altimeter the instrument should read zero on touchdown at that particular air field.(Strictly speaking this will show height of the altimeter above the ground at that airfield)

QNE = Is the altitude an altimeter will display with a standard setting of 1013.2 hPa (29,92" HG) on the sub scale, this indicated altitude is called the pressure altitude or flight level.