How do I add a working DME gauge to an FSX Cessna 152?

To add a working DME gauge to a Cessna 152 in FSX or FSX: Steam Edition, back up its panel.cfg, add the stock Bendix King DME to an unused 2D panel window, then power the avionics and tune a DME-capable station. Configuration alone cannot create a new 3D cockpit instrument.

What is the safest way to add the DME gauge?

A separate pop-up window is the safest option because it avoids covering existing instruments or editing the Cessna 152 panel bitmap.

1. Find the active panel folder. Open SimObjects\Airplanes\<C152 aircraft folder> inside your FSX installation. Check the selected livery's [fltsim.x] section in aircraft.cfg. A blank panel= entry uses the panel folder; an entry such as panel=classic uses panel.classic.
2. Exit FSX and back up panel.cfg. If the file contains an alias= line, it is borrowing another aircraft's panel. Editing the aliased panel changes every aircraft using it. To customise only the C152, copy the complete aliased panel folder into the C152 and edit that local copy instead. Our instructions for setting up an aircraft-specific 2D panel folder explain this arrangement.
3. Choose the next unused window number. If the existing sections run from [Window00] to [Window05], use [Window06]. Under [Window Titles], add Window06=DME. Do not reuse a number or leave the title and section numbers mismatched.
4. Add the new window section. Place the following entries on separate lines at the end of panel.cfg:
   • [Window06]
   • size_mm=156,41
   • position=8
   • visible=0
   • ident=10080
   • BACKGROUND_COLOR=0,0,0
   • gauge00=Bendix_King_Radio!Bendix-King Radio DME, 0,0,156,41

   If Window06 or ident=10080 is already present, substitute unused values consistently.

5. Save the file as plain text. Ensure Windows has not renamed it panel.cfg.txt. If the simulator is installed under a protected folder, edit a copy elsewhere and copy it back with administrator permission.
6. Open the DME in FSX. Load the C152 and select Views, then Instrument Panel and DME. The corresponding Shift-number shortcut may also work when the window falls within FSX's assigned panel shortcuts.

This example uses the standard FSX gauge call Bendix_King_Radio!Bendix-King Radio DME, so no additional gauge download should be necessary in a complete FSX installation.

Should the DME go in the pop-up, main panel or virtual cockpit?

Use a pop-up for the least disruptive installation, or place the gauge in an existing 2D window when the panel artwork has suitable free space.

To place it directly in an existing 2D section such as [Window00], add gaugeNN=Bendix_King_Radio!Bendix-King Radio DME, x,y,width,height. Replace NN with the next unused gauge number. The coordinates use that window's size_mm coordinate system, not necessarily the bitmap's raw pixel dimensions.

A mistake we see constantly is adding a gauge line to a [VcockpitNN] section and expecting a new instrument to appear on the dashboard. A virtual cockpit needs a gauge polygon and texture mapping built into the aircraft model. Without those, retain the pop-up window while flying from the virtual cockpit.

How do I make the DME show a distance?

The DME will display a distance only when it has electrical power and is tuned to a facility carrying DME information.

• Turn on the battery or master switch and the avionics master, where fitted.
• If the gauge has its own frequency controls, tune the DME unit directly. If it offers a remote NAV1 or NAV2 source, select that source and tune the corresponding navigation radio.
• Use a VOR/DME, VORTAC or ILS/DME facility. An ordinary VOR, localiser, NDB or COM frequency does not provide DME.
• Remain within reception range and reasonable line of sight. Terrain and distance can prevent a valid indication.
• Use frequencies represented in FSX's navigation database. A present-day chart may not match the older facility data installed in FSX.

DME reports slant-range distance in nautical miles, not horizontal GPS distance. The difference is most noticeable when the aircraft is high and close to the station. Groundspeed and time-to-station indications may also fluctuate during turns because they are calculated from the rate of change in DME distance.

Why is the new DME gauge blank or missing?

A missing window normally indicates a panel configuration error; a visible unit showing dashes usually indicates a power, tuning or station problem.

• DME is absent from the panel menu: Confirm that Window06=DME and [Window06] use the same unused number, and that you edited the panel variant selected by aircraft.cfg.
• The window is black or empty: Check the gauge name character for character and confirm that a Bendix_King_Radio gauge module exists in FSX's Gauges folder. Repair the simulator's default files if that stock module is missing rather than obtaining an unknown replacement.
• The display contains dashes: Verify avionics power, frequency, source selection and whether the chosen station actually includes DME.
• A downloaded gauge will not load: A gauge compiled for a 64-bit simulator or a newer Microsoft Flight Simulator cannot run in 32-bit FSX. XML gauges must also retain their expected CAB or folder structure. Our FSX gauge installation and panel.cfg guide covers those file-placement cases.
• Your edits disappear or have no effect: Close FSX before editing, check for a panel alias, and make certain you saved the correct panel.cfg rather than a similarly named backup file.