Explicit equations for barometric altitude computations

Explicit equations involving only square root and summation operations are derived for computing barometric altitude from measured data. Three different expressions are obtained for the altitude ranges -1,000 ft to 32,500 ft, 32,500 ft to 45,000 ft, and 45,000 ft to 60,000 ft, which satisfy the accuracy requirements for pressure altitude given in an ARINC specification. Although implementation of the equations would not offer many advantages where advanced digital computation techniques are available, they go along with the equations for Mach number and airspeeds in the explicit forms given by Bogel (1974)