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RunupLab

True airspeed (planned)

Pre-flight TAS from CAS, pressure altitude, and the forecast static OAT, using compressible-flow relations on the ICAO standard atmosphere.

ALT & SPD

TRUE AIRSPEED (PLANNED)3/32SOLVED
kt
ft
°C

Reading the screen: cyan is a value you entered, green is a computed result, amber means a field still needs input or the entry needs a CHECK. SOLVED lights when every result is computed; STO keeps a value to reuse in another function; the line-select keys beside the screen pick the field the keypad edits.

How this is computed

Pre-flight TAS from CAS, pressure altitude, and the forecast static OAT, using compressible-flow relations on the ICAO standard atmosphere. Reproduces the ASA CX-3 manual's Planned TAS example to the last decimal: 125 kt CAS at 8,500 ft and −5 °C → 141.0 kt, M 0.221.

Keyboard shortcuts
  • / or Ctrl+K — jump to the function search
  • Digits, . or : (outside a field) — type into the scratchpad, then press a line-select key to insert
  • Arrow keys — move around the keypad; Enter opens the focused function
  • Home / End — start / end of a keypad row
  • Alt+18 — jump to a keypad group