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FOMS Menu 446 (TAS/Mach, Sunrise, Wind-TO/Lnd Program)

Note: The following descriptions represent the typical access and privileges afforded to users designated as Dispatch Managers/Supervisors. Users with dispatcher privileges will have limited access to a subset of the screens presented.


This program enables the user to perform various different calculations.

The calculations available are:

  • calculate true air speed for any given Mach and vice-versa
  • calculate the GMT (UTC) for sunrise and sunset at any latitude/longitude for any day of the year
  • calculate the effective crosswind and headwind components at the take-off distance required with these conditions

 The modes available are:

  • TAS/Mach Calculation, enter <1>
  • Sunrise/Sunset, enter <2>
  • Wind Effect on T/O or Landing, enter <3>
  • Screen
  • Hardcopy
  • Quit

TAS Mach Calculation

Given the flight level and air temperature, this program will calculate the true air speed for any given Mach number or vice versa.


Description automatically generated

Flight level: Enter the appropriate flight level.

ISA Deviation: Enter the deviation from ISA temperature, if known. If not, press <Enter> and input the Actual outside air temperature. in either case, the value not entered will be computed and displayed.

Mach Number/TAS: Enter the known value, and the equivalent other value will be displayed.

Mach numbers must be entered without the decimal point.

Sunrise and Sunset

This program allows you to calculate the GMT (UTC) for sunrise and sunset at any latitude and longitude position for any day of the year. You can then convert to any local time if you know the difference from GMT.


Description automatically generated

Month: Enter the month of the year in number form from 1 to 12, e.g., enter <3> for March.

Day: Enter the day of the month in number form from 1 to 31

Location: Enter the location an airport, waypoint, or latitude/longitude coordinates.

Once the last entry has been made, the program will calculate and display the times for sunrise and sunset.

Wind Effect on Takeoff or Landing

The purpose of this program is to calculate the effective crosswind and headwind components and the takeoff or landing distance that will be required with these conditions.

Runway Magnetic Heading: Enter the magnetic heading of the runway in use.

Wind Direction (Magnetic): Enter the wind direction in degrees magnetic.

Wind Speed (Knots): Enter the wind velocity in knots.

Corrected Zero-Wind Distance: Enter the chart zero-wind takeoff distance in feet adjusted for temperature and pressure altitude.

Corrected Airspeed (Knots): Enter the chart airspeed adjusted for temperature and pressure altitude.


Description automatically generated

When the last item has been entered, the program will calculate and display the crosswind component left or right, the headwind or tailwind component, and the runaway distance that will be required.

Screen Mode

This allows you to generate a report of the calculations which have been done in a given session. You cannot enter the Screen mode upon entering the program as is the case in most other programs. If you attempt to do so, a prompt No Data to REPORT is displayed. However, after you have done one or more calculations, you may call up the Screen mode and have a summary of your calculations displayed on the screen.

Hardcopy Mode

This mode works in the same manner as the Screen mode with the exception that the report is sent to the printer. As noted above, this mode should not be entered until after you have performed all of the calculations which you wish to perform.

Quit Mode

This mode allows you to exit this program and go directly to another program, or to return to the last menu.


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