Learn how to enable the HUD in FlightGear, read its flight data, adjust visibility, and fix missing, blank or misaligned symbology.
To enable FlightGear’s generic HUD, give the simulator window keyboard focus and press the lower-case h key; press it again to hide the overlay. It shows core flight data such as attitude, heading, airspeed and altitude. A modelled cockpit HUD is separate and may require electrical power, avionics and its own controls.
How do I turn the FlightGear HUD on?
The standard HUD toggle is the lower-case h key, without Shift.
- Select a forward-facing view. The cockpit view is usually the clearest place to learn the display.
- Give FlightGear keyboard focus. Click inside the simulator window and close any open dialogue, console or text field that may be capturing keystrokes.
- Press
honce. The generic HUD should appear over the scene. Press the same key again to remove it. - Adjust readability if needed. Use the HUD controls exposed by your FlightGear build to change available colour, brightness, transparency or display-style options.
- Cross-check the instruments. Treat the HUD as a compact presentation of simulator data, not as a replacement for the aircraft’s primary instruments.
Capital H can perform a different HUD-related function under common key maps, so do not hold Shift when trying to toggle the display. Bindings can also differ after an update or user modification; our guide to checking and remapping FlightGear keyboard commands explains how to verify the command used by your installation.
What does the FlightGear HUD show?
The generic HUD condenses essential flight information into the pilot’s forward view, although the exact layout and available symbols vary between configurations.
| HUD information | What it tells you | How to use it |
|---|---|---|
| Horizon and pitch references | Aircraft pitch and bank attitude | Use them to hold a climb, descent or level attitude without looking down at the panel. |
| Heading scale | Direction of flight or aircraft heading, depending on the layout | Roll out on the required heading and monitor turns. |
| Airspeed | Indicated or configured speed information | Watch it during take-off, climb and approach, then confirm it against the panel instrument. |
| Altitude | Aircraft altitude | Use it with the vertical trend or vertical-speed indication to capture and hold a level. |
| Flight-path or climb information | Where the aircraft is moving and how rapidly it is climbing or descending, when the selected layout provides it | Use it to refine an approach or maintain a steady climb, rather than chasing every small movement. |
A useful scan is attitude first, airspeed second, then altitude and heading. Avoid staring at one number: the HUD makes deviations easier to spot, but smooth corrections still depend on reading several cues together.
What is the difference between the generic HUD and an aircraft HUD?
FlightGear’s generic HUD is a simulator overlay, while a modelled aircraft HUD is part of that aircraft’s cockpit and systems.
| Type | How it is activated | What it requires |
|---|---|---|
| Generic FlightGear HUD | Normally toggled with lower-case h | Only the simulator command and a compatible view |
| Modelled cockpit HUD | Operated using controls provided in that aircraft | Electrical power, avionics or mission systems, a HUD power or brightness setting, and the correct pilot viewpoint may all be required |
Pressing h does not necessarily switch on the built-in display in a fighter or other HUD-equipped aircraft. Conversely, the generic overlay may work even when the aircraft is cold and dark. This distinction prevents a common mistake: troubleshooting the aircraft’s electrical system when the intended display was actually FlightGear’s generic overlay.
Why is the HUD not showing or readable?
Most missing-HUD problems come from keyboard focus, an altered binding, poor contrast or confusion between the generic overlay and a modelled cockpit display.
- Nothing happens when you press
h: click inside the main simulation window, close open dialogues and try the lower-case key again. Check the assigned HUD toggle if the control still does not respond. - The symbols are faint or appear blank: change the available HUD colour, brightness or transparency setting. A colour that works against terrain can disappear against bright cloud or sky.
- The aircraft’s own HUD remains dark: establish electrical power, switch on the required avionics or display system, then check its power, mode and brightness controls.
- Symbology is displaced or clipped: return to the intended pilot viewpoint and reset an extreme zoom level. Our explanation of changing the cockpit view and correcting viewpoint or zoom covers the relevant view controls.
- Only one add-on aircraft is affected: test the generic HUD with a standard included aircraft. If it works there, the problem is probably specific to the add-on’s display, configuration or systems rather than FlightGear’s global HUD command.
Can I use the HUD in external views?
The generic HUD may remain available in several camera views, but a modelled cockpit HUD normally works only when the viewpoint is correctly aligned with its combining glass.
Use the generic overlay externally when you need quick flight-state information, then return to the forward cockpit view for normal instrument flying. If a built-in HUD vanishes after moving the camera, centre the pilot viewpoint rather than changing aircraft systems; modelled HUD imagery is often deliberately visible only from a narrow eye position.