Fix an FSX altimeter that is frozen, inaccurate or will not reset. Check barometric pressure, the B key, weather, panel gauges and add-ons.
In FSX and FSX: Steam Edition, an altimeter that seems broken is usually using the wrong barometric setting, not suffering a gauge failure. Press B to set local pressure, then climb and check for needle movement. If it remains frozen, test a default aircraft to separate an add-on panel fault from a simulator-wide problem.
How do I fix an FSX altimeter that is not working?
The quickest fix is to reset the barometric pressure, then determine whether the fault follows one aircraft or affects every panel.
- Make sure FSX is not paused. Climb or descend several hundred feet and watch all the altimeter hands, not only the hundreds-of-feet hand.
- Press
B. This runs the Altimeter (reset) command and sets the instrument to the local pressure represented by FSX weather. Our FSX keyboard-command reference lists this and the related instrument controls. - Watch the pressure window. The Kollsman window or digital pressure value should change when the command is received. If nothing happens, give the FSX window focus and check whether
Bhas been reassigned or intercepted by add-on software. - Turn the barometric knob manually. If the setting changes but the needles remain fixed during a climb, the problem is with the gauge rather than the keyboard command.
- Load a default aircraft. Test an unmodified default Cessna at a default airport. If its altimeter works, repair the panel or gauges belonging to the affected add-on instead of reinstalling FSX.
- Compare the 2D panel and virtual cockpit. If only one representation is frozen, its gauge entry, panel configuration or model integration is faulty.
What does the altimeter symptom tell me?
| Symptom | Likely cause | What to check |
|---|---|---|
| Needles move, but the altitude is wrong | Incorrect pressure, weather or unit setting | Press B and check inHg versus hPa |
B does nothing, but the knob works | Missing or conflicting key assignment | Restore the Altimeter (reset) control |
| One add-on aircraft has a frozen gauge | Missing, incompatible or misconfigured gauge | Restore its original panel files or reinstall that aircraft |
| Digital altimeter or entire display is blank | Electrical power, avionics or gauge-module problem | Check the battery, generators, avionics master and add-on startup procedure |
| Altimeter works, but the aircraft will not hold altitude | Autopilot mode or aircraft-trim problem | Check altitude-hold engagement rather than replacing the altimeter |
Why does the FSX altimeter show the wrong altitude?
An altimeter set to local QNH should indicate approximately the airport's elevation above mean sea level while the aircraft is on the ground; it is not supposed to read zero. Zero on the runway requires QFE, which is a different pressure reference.
29.92 inHg and approximately 1013 hPa represent standard pressure. Use standard pressure above the applicable transition altitude, but use the local setting supplied by weather or ATC below it. A common mistake we see is leaving standard pressure set during departure or arrival and then assuming the gauge has failed.
Pressure injected by an add-on weather engine can also differ between locations or change as a new weather station becomes active. For a detailed explanation of QNH, QFE, pressure units and scenery-elevation discrepancies, see our guide to diagnosing incorrect simulator altitude indications.
If the instrument looks correct but FSX ATC repeatedly reports the aircraft high or low, reset the setting when ATC issues a new pressure value. Persistent disagreement can come from an add-on gauge using a different pressure reference; our FSX ATC altitude troubleshooting covers that specific case.
Why is the altimeter frozen only in an add-on aircraft?
A frozen altimeter confined to one aircraft is an aircraft-panel fault, not a general FSX failure. Modified panel.cfg entries, missing gauge files, an incorrect panel alias or a gauge module that was not allowed to load are the usual causes.
- Restore the aircraft's original panel folder if the problem began after editing or installing a replacement panel.
- Reinstall the affected aircraft from a clean package rather than copying unrelated gauges into it.
- If FSX asks whether to run a gauge module, permit it only when it belongs to an add-on you trust. Refusing a required module may leave instruments blank or inactive.
- For a glass cockpit, complete the aircraft's electrical startup procedure. Unlike the default mechanical altimeter, an electronic display may remain blank without battery, generator or avionics power.
Could this be an autopilot problem instead?
If the altitude indication changes normally but the aircraft climbs through or drifts away from the selected altitude, the altimeter is working. Check that the autopilot and the intended altitude mode are engaged, and remember that add-on aircraft may use different capture logic from the default panels. Our FSX autopilot operating guide explains the relevant altitude controls.
When no default aircraft altimeter responds during a real climb or descent, restart FSX and retest with an unmodified default flight. If the fault remains across every aircraft, back up add-ons and use the installation repair option for boxed FSX or file verification for FSX: Steam Edition, since a core gauge or panel file may be damaged.