Average ISA Deviation

Instantly calculate average ISA deviation for accurate FMC descent planning on the B737. A fast, offline tool built by pilots for pilots.

Average ISA Deviation is a fast and precise utility designed for pro pilots who need to calculate the average ISA temperature deviation to correctly enter the DES FORECAST in the FMC of the Boeing 737 (NG / MAX) and other aircraft.

The app allows you to: • Quickly calculate the average ISA deviation • Reduce workload and potential errors during descent planning • Simplify calculations that are normally done manually • Work fully offline, ideal for cockpit use

Designed by a pilot, for pilots.

Legal Disclaimer This application is intended as an advisory and informational tool only. It does not replace official aeronautical charts, flight planning systems, company procedures, or regulatory guidance.