Example 1:
Lookup QNH = 1020 in the left column of the table.
The corresponding correction in the middle column is -200 ft.
The elevation is 2500ft, after correction it is 2500-200 = 2300ft.
Look this value up on the right side of the scale on the left side of the picture and read the corresponding QFE on the left side of the scale. QFE = 933 hPA
Example 2:
Locate QFE = 980 hPA on the left side scale and find that the corresponding pressure altitude reads 920 ft. The actual elevation is 1500 ft, so the correction is (920-1500) = -580 ft.
Looking up -580 in the middle column of the table yields the corresponding QNH of 1032 hPA in the left column.
ATCast