The OPTIM computer program was developed to generate optimum vertical profiles for turbojet powered aircraft. Specifically, OPTIM generates a profile of altitude, airspeed, and flight path angle as a function of range between a given set of origin and destination points for particular models of transport aircraft. The profile may be optimized in the sense of minimizing fuel or time or in minimizing the direct operating cost expressed as a combination of fuel and time. Inputs to the program include the vertical wind profile, the aircraft takeoff weight, and the aircraft engine and aerodynamic characteristics. The optimum vertical flight profile is generated by calculating the airspeed and thrust required to minimize the Hamiltonian at specific energy increments. (Analytical Mechanics Associates for NASA Langley)
This program was released through COSMIC as program LAR-12940. The italicized text above is from the official COSMIC release.