ACARS Message Sandbox

Build ACARS transmissions in your browser. Xbox and PC crews can rehearse the templated flow here before jumping into the RealRadio client. Nothing you create on this page is transmitted—use it as a safe rehearsal space or as a development harness while the backend endpoints firm up.

1 Select a category, subcategory, then phrase.

2 Review auto-filled SimVars and tweak any fields.

3 Copy the output or add it to your sandbox log.

Flight context

Start with canned demo data or, when signed in, pull your last MSFS session to match what the in-sim RealRadio client will send.

Callsign Flight # Tail Airframe Origin Destination Departure (UTC) ETA (UTC) Phase Position Altitude Route / Clearance SELCAL Fuel remaining

Using example flight plan.

ACARS message composer

Use the dropdown menus to browse the seeded categories, then personalise the dynamic fields before copying.

Loading library…

Select a phrase to configure its dynamic fields.

Message text

Select a phrase to preview the message.

Payload JSON

/* Select a phrase to generate payload JSON */

Sandbox log

Messages here are stored in-memory only—perfect for rehearsing flows with your crew.

Compose a message and choose “Add to sandbox log” to start a trail.

How it maps to MSFS

Use these notes while building the in-sim panel or testing bindings.

Library source: seeded JSON (acars_menu.json) ships with the seeder. The sandbox will call ~/ops/acars/menu when the endpoint is available, falling back to the embedded training data.
Flight snapshot: matches the data packet the MSFS client emits (callsign, route, SELCAL, SimVars). When signed in the “Load session” button should hit ~/msfs/session/last (to be implemented) and map fields automatically.
Dynamic fields: the same tokens you use in the sim—Callsign, Position, Engine#, Timestamp, etc. Editing them here gives you a 1:1 preview of the outgoing text and JSON payload.

API hand-off checklist

Expose GET ~/ops/acars/menu returning the seeded structure ({ version, categories[] }).
Expose GET ~/msfs/session/last for authenticated users (returns latest flight snapshot or 404).
Wire POST ~/acars/messages to enqueue sandbox submissions. Payload mirrors the JSON preview shown here.
Emit SignalR updates (optional) to populate the future operations centre dashboard when real sending is enabled.

Each step is documented inline in the JS module so future you knows exactly where to plug things in.

Payload template

The sandbox emits a ready-to-send shape:

{
  "messageKey": "FUEL_LOW",
  "category": "EMERGENCY",
  "subcategory": "SYSTEM_CRITICAL",
  "dynamicFields": [
    { "name": "Callsign", "value": "RRX321" },
    { "name": "Position", "value": "N52.12 W030.44" },
    { "name": "Timestamp", "value": "2025-09-15T19:52:00Z" }
  ],
  "flight": {
    "callsign": "RRX321",
    "route": "CPT UL9 STU NAT-Z QUBIS",
    "origin": "EGLL",
    "destination": "KJFK"
  }
}

Drop this straight into a dev console or postman call once the backend is wired.

ACARS Message Sandbox

Flight context

ACARS message composer

Category

Subcategory

Phrases

Sandbox log