Replay any flight from a .telem file

Flight Replay plays a recorded .telem file back through the same telemetry pipeline that drives a live flight. The Pad, Flight, Map, and Recover tabs all update exactly as if the rocket were flying right now — state transitions, voice announcements, map track, the lot. This is how you re-watch a flight with full visual context, demo the app without a rocket on the rail, or verify a file captured cleanly all the way to landing.

What replay actually does

Most “replay” features in other tools are a slider across a static chart. Replay in AltosUI is different: it feeds the recorded packet stream into the live pipeline, so every display behaves the way it did during the real flight. The state machine walks from pad to boost to coast to drogue to main to landed on the same triggers. The voice callouts speak on the same transitions. The Recovery Map draws the same track as the packets arrive.

In practice that means the experience of watching a replay is close to the experience of watching a live flight — which is exactly what you want when you’re doing a post-flight debrief with someone who wasn’t at the launch, or walking through what happened during an anomaly.

Playback controls

The controls are deliberately minimal:

Play / Pause — start and stop the packet stream.
Skip forward / back — jump between files when you have several recordings loaded.
Jump to start — restart the current flight from the first packet.

There’s no scrub bar and no speed knob because the timing modes below cover the two cases people actually need.

Two timing modes

You pick between Actual and Fast depending on what you’re doing with the replay.

Actual timing. Packets arrive at the same intervals they originally arrived. A 60-second flight takes 60 seconds to replay. This is the mode you want when you’re studying what happened in real time — watching voice callouts land in sequence, seeing state transitions in context, or showing someone what the app looked like during an ascent.
Fast timing. Packets arrive at one-second intervals regardless of their original spacing. An entire flight blows past in a minute or two. This is the mode for quickly scanning a recording — most practically, for verifying that a .telem file actually captured all the way to landing and wasn’t truncated by a signal dropout.

When you’d reach for replay

Three scenarios where replay earns its keep:

Post-flight review with context. The Flight Report gives you the numbers and the advisories. Replay gives you the lived experience of the flight — same displays, same transitions, same pacing. The two complement each other: you read the report to know what happened, you run the replay to feel how it happened.
Demos without a rocket on the rail. Handing your phone to someone curious about the app, pulling up a recorded flight, and hitting play is a better demo than any screenshot. They see every tab behave in sequence instead of poking at a static UI.
Verifying a recording. Run Fast timing on a .telem file and watch for the landed state. If you see it, the file captured all the way through; if the stream ends earlier, you know the flight is truncated and the report will carry a Signal Loss warning.

What files replay works with

Any .telem file the app can see. That includes files AltosUI wrote itself during a live flight, and files you brought in from somewhere else — AirDrop from another phone, email attachment, iCloud Drive, or the Files app. See working with .telem files on iPhone for how those files move around on iOS.

Replay works with recordings from every supported flight computer — TeleMega (v1 through v7), TeleMetrum (v1 through v4), TeleMini (v2 through v3), and TeleGPS (v1 through v4). What you see during playback matches what that specific hardware sent at flight time: TeleMini recordings have no GPS displays, TeleGPS recordings use the simplified pad/flying/landed state machine, and so on.

What you need

One or more .telem files the app can reach.
No TeleBT receiver is required — replay runs entirely off recorded data.