Altimeters (even on the most advanced aircraft) indicate correctly only if the temperature of the atmosphere is equal to the values of the International Standard Atmosphere (ISA).
When the temperature is lower than ISA, then your true altitude is lower than the indicated altitude!
Instead of applying corrections with this not so easy table :
… you can select inputs and display results right on approach profile.
Set you approach type #
It can be ILS, APV (minima VNAV or RNP), NPA3D (mode VNAV or FINAL APP) or NPA2D (mode VS or FPA)
it will modify the input fields as altitudes needed to be corrected depend on which approach you are performing.
Set Airfield data #
Airfield altitude and ground temperature : it will compute ISA.
Set your procedure altitudes #
- MOCA (actually the safety altitude considered)
- Intercept altitude (the last altitude to intercept the final path)
- Check Alt 1 and/or 2 (NPA3D NPA2D)
- GA altitude
- Slope (NPA2D)