# Use the HUD

> <mark style="color:$danger;">NOT FOR OPERATIONAL USE</mark>
>
> <mark style="color:$danger;">The AvComp HUD is a personal reference aid. Always use approved company, aircraft, ATC, and regulatory sources for operational decisions.</mark>

## <mark style="color:$warning;">What the HUD is</mark>

The HUD is a compact flight information panel that appears when an OFP session is loaded. It gives quick access to phase-relevant data without requiring you to stay inside the full OFP Brief page.

It is opened from the floating **HUD** pill. When open, it shows:

* A phase selector.
* Current UTC.
* Key fields for the selected phase.
* Editable overrides for many values.

<figure><img src="/files/cgnGZXIIBo4UGn2mxVxU" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/E62qzqss24d0Ea8U3cl6" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/KhzqAQJrR6eyCLHr1VL6" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/OMQyIZE8UTxU1S0tg3ht" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/OfoYdHj1XdCuFOk96N9O" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">When the HUD appears</mark>

The HUD appears only after an OFP has been loaded. If no OFP session is active, the HUD stays hidden.

The HUD can use data from:

* The loaded OFP.
* The ATC Clearance tool.
* Waypoint entries from OFP Brief.
* Manual HUD edits.
* Taxi route data from ATC Clearance.

## <mark style="color:$warning;">Phase selector</mark>

The phase row contains five phase buttons:

| Phase | Use                                                                                        |
| ----- | ------------------------------------------------------------------------------------------ |
| GND   | Before off-block. Clearance, runway, initial altitude, and departure ATIS.                 |
| TAXI  | After off-block and before takeoff. Runway, ground/tower frequency, and taxi instructions. |
| CLB   | Climb. Departure frequency, next waypoint, ETA, target FL, and squawk.                     |
| CRS   | Cruise. Flight level/Mach, squawk, VHF, AFOB, and cost index.                              |
| DESC  | Descent. STAR, arrival ATIS, landing fuel, alternate fuel, and next frequency.             |

Tap any phase button to select it manually. The selected phase is saved locally.

## <mark style="color:$warning;">Automatic phase behavior</mark>

If no manual phase is saved, AvComp derives the HUD phase from OFP session times:

* No actual off-block time: **GND**.
* Off-block entered but no takeoff time: **TAXI**.
* Takeoff entered and no arrival time: **CRS**.
* Arrival time entered: **DESC**.

Manual selection overrides this derived phase until changed.

## <mark style="color:$warning;">GND phase</mark>

GND is designed for departure clearance review.

Fields shown:

* Callsign.
* SID.
* Runway.
* Initial altitude.
* Clearance delivery frequency.
* Departure ATIS.

Most values can come from ATC Clearance. Departure ATIS is a manual HUD entry.

<figure><img src="/files/cgnGZXIIBo4UGn2mxVxU" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">TAXI phase</mark>

TAXI is designed for after off-block and before takeoff.

Fields shown:

* Callsign.
* Runway.
* Ground frequency.
* Tower frequency.
* Taxi instructions.

Taxi instructions use the ATC taxi route format. Tap the taxi field to open the taxi keypad and build or edit the route.

<figure><img src="/files/E62qzqss24d0Ea8U3cl6" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">CLB phase</mark>

CLB is designed for initial climb and early route tracking.

Fields shown:

* Callsign.
* Departure frequency.
* Next waypoint.
* ETA.
* Target flight level.
* Squawk.

The next waypoint and ETA are derived from the OFP waypoint table where possible.

<figure><img src="/files/KhzqAQJrR6eyCLHr1VL6" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">CRS phase</mark>

CRS is designed for cruise monitoring.

Fields shown:

* Callsign.
* Flight level / Mach.
* Squawk.
* VHF.
* AFOB.
* Cost index.

The AFOB field can use the latest actual fuel entry from the OFP waypoint table. Fuel color reflects the difference from the planned EFOB curve:

| Color                                      | Meaning                                                |
| ------------------------------------------ | ------------------------------------------------------ |
| <mark style="color:$success;">Green</mark> | Actual fuel is close to or above planned projection.   |
| <mark style="color:$warning;">Amber</mark> | Actual fuel is moderately below planned projection.    |
| <mark style="color:$danger;">Red</mark>    | Actual fuel is significantly below planned projection. |

<figure><img src="/files/OMQyIZE8UTxU1S0tg3ht" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">DESC phase</mark>

DESC is designed for approach preparation.

Fields shown:

* Callsign.
* STAR.
* Arrival ATIS.
* Landing fuel.
* Alternate fuel.
* Next frequency.

Landing fuel may be estimated from the latest actual fuel entry and the OFP planned EFOB curve.

<figure><img src="/files/OfoYdHj1XdCuFOk96N9O" alt=""><figcaption></figcaption></figure>

## <mark style="color:$warning;">Editing HUD fields</mark>

Tap a HUD field to edit it. Edits are stored locally and override the value shown in that HUD field.

Frequency fields open the frequency keypad. Other fields open a text edit modal.

Fields that often come from other tools can still be edited in the HUD if you want a temporary override.

## <mark style="color:$warning;">Callsign</mark>

The callsign field uses this priority:

1. Manual HUD callsign.
2. Callsign parsed from the OFP.
3. Airline plus flight number from the OFP.

Tap the callsign field to override it.

## <mark style="color:$warning;">Fuel check reminder</mark>

The HUD can show a fuel check overdue alert. It fires 55 minutes after the latest logged waypoint ATA.

When triggered, AvComp displays a fuel alert banner and may play a tone or vibrate if supported by the device.

Tap the alert to dismiss it.

## <mark style="color:$warning;">Storage</mark>

HUD data is stored locally on the device. It may be lost if browser site data is cleared.

Saved HUD items include:

* Manual phase selection.
* Callsign override.
* Phase-specific field overrides.

Taxi route data is stored with the ATC Clearance data.

## <mark style="color:$warning;">Recommended workflow</mark>

1. Load and verify the OFP in OFP Brief.
2. Record departure clearance in ATC Clearance.
3. Open HUD and check GND fields.
4. Use TAXI phase during taxi if the taxi route builder is useful.
5. Use CLB or CRS after departure.
6. Enter waypoint ATA and AFOB values in OFP Brief so HUD cruise fuel data stays useful.
7. Use DESC for arrival setup notes.

## <mark style="color:$warning;">Limitations</mark>

* HUD values are only as reliable as the loaded OFP, ATC entries, waypoint entries, and manual edits.
* HUD does not validate operational clearance correctness.
* Fuel estimates are advisory and depend on entered actual fuel and OFP planned values.
* Live vibration support depends on device and browser.


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