// START HERE · FIRST CONNECTION

First connect

iOS 1.2.0 ON THE APP STORE · UPDATED 9 SEPTEMBER 2026

Everything here is done once. The step people get stuck on is the third one: a FlySight will not accept a new phone unless you ask it to, on the device itself, with a double-press.

Confirmed on real hardware: an iPhone finding a FlySight 2, pairing off the double-press and showing live telemetry. The same path on Android is built but has no hardware run recorded here.

1. Install the app

On iPhone, Groundrush is on the App Store. It is free, there is no account to create and it updates itself.

On Android, Groundrush is on Google Play. Free there too, with no account to create.

2. Switch the FlySight on, and unplug it

Press the FlySight button to switch it on. If it is plugged into USB, unplug it: while the logger is mounted as a USB drive its firmware blocks Bluetooth file access, and it has to be switched on and idle before it will answer a phone.

3. Open the Device tab

Open Groundrush and tap Device in the bottom bar. The scan starts when you open that tab and stops when you leave it, which is why nothing asks for Bluetooth permission the moment the app opens.

Bluetooth has to be switched on. On Android 11 and older the Location permission is needed as well — Groundrush never uses your position, but Android returns no scan results at all without it. If either is missing the app says which one it is and offers the settings page rather than spinning.

4. Put the FlySight into pairing mode

This is the part that is done on the logger, not on the phone.

With the FlySight switched on and idle, double-press its button — two presses in quick succession, the same button you use to switch it on.
Watch the LED. A slow green pulse, about one every 2 seconds, is pairing mode.
If the LED does not pulse green, the double-press did not register. Press again.

The pairing window lasts about 30 seconds. If it runs out before the phone gets there, double-press again — nothing is broken.

5. Connect

Your FlySight appears in the list under Devices found, with its signal strength in dBm. While it is inside the pairing window the app marks it ready to pair.
Tap it.
Your phone raises its own pairing request. Accept it.

That is the whole button dance, and it is not needed again. Next time, the Device tab opens with a Last used card at the top: one tap on Connect and it reconnects.

6. What a connected FlySight looks like

The bar at the top of the Device tab is on screen in every state, so you never have to guess. Connected, it reads Connected to your FlySight's name, with a battery percentage beside it and a pulsing dot.

Underneath, the live screen shows vertical speed (positive is down, as the logger reports it), horizontal speed, altitude and glide ratio, and a status strip with satellites, fix quality, battery, mode and the firmware version the device is running. Values stay dimmed until real data arrives — outdoors, with sky above it, a FlySight needs a moment to find satellites.

Below the live figures are the three things worth opening next: Tracks on the device, HUD & glasses and Firmware update.

If something does not work

"No FlySight found". Check that it is switched on, not plugged into USB and within a few metres. If another phone is connected to it right now, close the app there first: a FlySight stops announcing itself while a phone is connected, so nobody else can find it. ENGO glasses do not get in the way — the logger connects out to those itself.
"Bluetooth is switched off". Switch it on in the phone settings; the list starts by itself as soon as you do.
A permission was denied. The app names the missing one — Nearby devices on Android 12 and newer, Location before that — and opens the app settings for you.
"Pairing did not complete". Almost always the 30 seconds ran out. Double-press again and tap Connect straight away.
It paired before and now refuses. The bond has to be cleared on both sides: "Forget this device" in the phone's Bluetooth settings, and Reset_BLE = 1 in FLYSIGHT.TXT on the FlySight over USB.
Anything else. Write to hello@groundrush.io.

Where to go next

Download tracks over Bluetooth — browse the recordings on the logger and copy a jump to the phone at the dropzone.
Use an ENGO 3 HUD with FlySight 2 — install the HUD firmware, bind your glasses and choose what the display shows.
The roadmap — what has been proven on real hardware, and what has only been built.

Groundrush is a companion, not an instrument. Do not fly it as your only source of altitude — the numbers you rely on should come off the equipment you already trust.

Groundrush is an independent project and is not made by, endorsed by or affiliated with FlySight.