> ## Documentation Index
> Fetch the complete documentation index at: https://docs.czautoz.co.uk/llms.txt
> Use this file to discover all available pages before exploring further.

# HUD & Fuel

> In-cockpit HUD showing airspeed, altitude, health, pilot control, and Autohover status. Audio fuel warnings with configurable threshold.

## HUD

The helicopter HUD is displayed for both the **pilot and co-pilot** whenever they are seated in a cockpit seat. It shows:

| Element                     | Description                                                                          |
| --------------------------- | ------------------------------------------------------------------------------------ |
| **Airspeed**                | True airspeed in knots — smoothed to remove needle and number jitter                 |
| **Altitude AGL**            | Height above ground level in feet                                                    |
| **Health Bar**              | Current helicopter HP                                                                |
| **Pilot Control Indicator** | **Green** when you hold flight control, **red** when the other cockpit seat holds it |
| **Autohover Status**        | Whether Autohover is currently active                                                |
| **Light Status Icons**      | Whether the spotlight and navigation lights are on or off                            |

***

## Fuel System

### Fuel Capacity & Burn Rate

| Helicopter       | Tank Capacity | Burn Rate  | Approx. Flight Time |
| ---------------- | ------------- | ---------- | ------------------- |
| MD500 Civilian   | 242 L         | 120 L/hr   | \~2h 00m            |
| MH-6 Little Bird | 245 L         | 150 L/hr   | \~1h 38m            |
| SA342M Gazelle   | 455 L         | 280 L/hr   | \~1h 38m            |
| UH-1H Iroquois   | 840 L         | 300 L/hr   | \~2h 48m            |
| MH-60L Blackhawk | 1,360 L       | 1,100 L/hr | \~1h 14m            |
| AW101 Merlin     | 4,100 L       | 900 L/hr   | \~4h 33m            |

### Unlimited Fuel

Set `fuel.burnLPH` to `0` to disable fuel consumption entirely.

### Custom Flight Duration Formula

```
fuel.burnLPH = (fuel.maxCapacity / desired_flight_minutes) * 60
```

**Example** — UH-1H for exactly 2 hours of flight:

```
fuel.burnLPH = (840 / 120) * 60 = 420
```

### How to Refuel

There are two ways to refuel a helicopter:

**From a container** — hold a fuel container, approach within `fuel.refuelDistance` metres of the helicopter, and look at the **fuel refill point** on the helicopter's model. The refuel action will appear — activate it to transfer fuel from the container into the tank.

**At a fuel station** — park near a working fuel station and use the built-in **pump-refuel** action. No jerry can is needed, and the fill rate is faster than a container.

**Accepted fuel sources:**

| Source                                    | Notes                                                                                                 |
| ----------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| `CanisterGasoline` (jerry can)            | Standard refuel. Default: fills 10% of any tank per full can.                                         |
| `CZAutoz_HeliDrum` (Helicopter Fuel Drum) | Large drum. Default: fills 50% per drum — 2 drums to fill any helicopter from empty.                  |
| `Bottle_Base` items                       | Water bottles, glass bottles, etc. Very small fill per bottle.                                        |
| Fuel station (built-in)                   | Vanilla, Enoch, or a Simple Gas Pump — pump-refuel directly with no container, at a faster fill rate. |

Refuel amounts and drain speed per container type are configurable in `mod_config.json`. See [Global Settings](/server-config/global-settings#refuelling) for the full table.

<Note>
  Helicopters spawned by the Central Economy (`types.xml` / `events.xml`) start with a **partial fuel load** rather than empty or full.
</Note>

### Refuel Settings

| Setting                | What it does                                                                                                                                                 | Default |
| ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------- |
| `fuel.refuelOnRestart` | `1` = helicopter refuels to full on each server restart. Does not affect fresh spawns — admin-spawned helicopters always respect the spawner's fluid choice. | `1`     |
| `fuel.refuelDistance`  | Max distance in metres for the refuel action to appear                                                                                                       | `5.0`   |

### Fuel Warning System

Audio warning beeps alert the crew when fuel is running low:

* Beeps begin at the configured fuel fraction threshold
* The beep interval **shortens as fuel continues to drop** — urgency increases
* Both pilot and co-pilot hear the warning

| Setting                      | What it does                                                                                    | Default |
| ---------------------------- | ----------------------------------------------------------------------------------------------- | ------- |
| `gameplay.fuelWarnThreshold` | Fuel fraction at which beeps begin. `0.20` = starts at 20% remaining. Set in `mod_config.json`. | `0.20`  |
| `audio.warningVolume`        | Volume of the fuel warning beep and rotor emergency alarm                                       | `1.0`   |

<Note>
  The fuel warning threshold lives in `mod_config.json` under `gameplay`. Audio volume settings (`audio.engineVolume`, `audio.rotorVolume`, `audio.warningVolume`, `audio.crashVolume`) are configured per variant in each helicopter's JSON file under the `audio` section. See [Per-Helicopter Settings](/server-config/per-helicopter-settings#audio) for the full table and per-variant tuning details.
</Note>