Use this page to diagnose a degraded or non-working Horizon system, whether the aircraft is on the ground or in flight. Confirm the basics below, then find your symptom in the index and follow the linked procedure.

Before you troubleshoot

Confirm the basics first — most link faults resolve here:

1. Both Hardware Units powered on, STATUS LED solid green (see LED Quick Reference).
2. Every antenna connected before power was applied (never transmit with an antenna disconnected).
3. GCS computer has an active internet connection.
4. Correct COM port selected in the GCS application at baud rate 57600 (typically the higher-numbered of the two enumerated ports).
5. UDP connection in the GCS application set to 127.0.0.1 : 14550.

Note

If a fault is intermittent or performance is degraded rather than absent, it is usually a physical-layer problem — antenna placement, RF cable routing, EMI coupling, or LOS channel separation. Start with Link-Quality Diagnosis.

Symptom index

Symptom	Probable cause	First action
GCS application cannot connect over LOS	Mismatched LOS frequency, unset device name, LOS radios disabled, wrong COM port, or flight controller serial config	LOS Link Cannot Be Established
No COM ports enumerate when GCS unit is plugged in	USB-C cable not seated, not data-capable, unit unpowered, or missing USB serial driver	Hardware Unit Not Detected
No BLOS telemetry; aircraft not on Somewear web map	SAT antenna disconnected, obstructed sky view, inactive satellite data plan, or flight controller config	No Telemetry Received Over BLOS
Aircraft on Somewear web map but not in GCS application	Wrong device selected in Horizon UI, or GCS computer offline	No Telemetry Received Over BLOS
BLOS commands stay pending in the satellite queue	BLOS link also down, or stalled queue	BLOS Commands Stuck in Queue
Horizon UI shows “Missing API Key”	GCS computer was offline at sign-in, or no key entered	Horizon UI Displays “Missing API Key”
Beam or Horizon UI in-app update fails to reload	Corrupted in-app update	Beam Install Fails to Update
Intermittent or degraded link, high error rate	Antenna siting, RF cable routing, EMI, or channel separation	See Link-Quality Diagnosis
Total loss of link (both LOS and BLOS) during flight	Both the radio and satellite links are down at once	Total Loss of Link — GCS Crew Actions
Horizon UI or Beam stops responding during a mission	Application crash or hang	Horizon UI or Beam Crash During Mission

For an orientation to the screens named below, see the Horizon UI Tour.

LOS Link Cannot Be Established

Symptom: GCS application cannot connect over LOS.

1. Confirm both Hardware Units share matching Radio Settings ranges and the radio is enabled, on the Connected Device screen.
2. Confirm both Hardware Units have a unique Name. Without a name, LOS encryption keys are not set and the link will not close.
3. Confirm the LINK LED on both units is fast-blinking green (LOS closed). See LED Quick Reference.
4. Verify flight controller serial-port configuration (see Flight Controller Configuration) and confirm the flight controller is powered.
5. In your GCS application, confirm the UDP connection is 127.0.0.1 : 14550, matching the aircraft’s UDP Port and Preferences. No COM-port selection is required.

GCS Hardware Unit Not Detected

Symptom: The unit does not appear in Connected Device when connected.

1. Verify the USB-C cable is firmly seated at both ends.
2. Verify the USB-C cable is data-capable.
3. Confirm the unit is powered. USB-C does not power the unit — use the modified AC wall adapter (GCS) or the aircraft battery.
4. Try a different USB-C cable.
5. Confirm the unit’s STATUS LED is solid green.
6. Check Device Manager for unrecognized USB devices and install any required USB serial drivers.

No Telemetry Received Over BLOS

Symptom: GCS application shows no BLOS telemetry; the aircraft is not appearing on the Beam web map.

1. Verify the aircraft satellite antenna is connected to the SAT port on the Aircraft Hardware Unit.

2. Ensure the aircraft has a clear, unobstructed view of the sky. Move away from buildings or overhead structures.

3. Confirm the device’s satellite data subscription/plan is active.

4. Verify flight controller configuration (see Flight Controller Configuration) and power.

5. If the aircraft is appearing on the Beam web map but not in the GCS application:

   • Confirm the correct aircraft is added and selected in Fleet View.
   • Verify the GCS computer has an active internet connection.

BLOS Commands Not Clearing the Flight Log

Symptom: Commands sent to the aircraft show Pending or Sending in the aircraft card’s Flight Log but do not reach Delivered.

1. If telemetry is also not being received, troubleshoot the BLOS link per No Telemetry Received Over BLOS first.
2. If telemetry is received but tasks are not clearing, select Clear Queue on the aircraft card, then re-issue the commands.

Horizon UI Displays “Missing API Key”

1. Verify the GCS computer has an active internet connection. If it was disconnected, restart the Beam server after reconnecting.
2. Open Diagnostics from the navigation rail and select the Config tab.
3. Confirm an api-key value is present. If missing, add or enter it (an Organization Admin provides the key).

Beam or Horizon UI In-App Update Fails

Symptom: Updating from within the application causes it to fail to reload.

1. Fully uninstall Beam (Control Panel → Programs → Uninstall Somewear Local).

2. Download the latest Beam client from:

   https://somewear.app/app/settings/downloads

3. Perform a clean reinstallation using the wizard.

4. Confirm Beam starts correctly after the clean installation.

Total Loss of Link — GCS Crew Actions

If all communications with the aircraft are lost (both LOS and BLOS):

1. Verify GCS Hardware Unit power and USB-C connection. (USB-C carries data only; confirm the unit is powered from the AC wall adapter.)
2. Verify internet connectivity on the GCS computer.
3. Attempt to restore LOS by repositioning the GCS antennas.
4. If the aircraft is equipped with a Return-to-Launch (RTL) failsafe, allow it to execute autonomously.
5. If a BLOS link was recently active, allow time (up to several minutes) for a satellite connection to re-establish before issuing additional commands.

Horizon UI or Beam Crash During Mission

If Horizon UI or the Beam server stops responding, the UDP passthrough to the GCS application is interrupted.

1. Relaunch immediately: select the Beam tray icon and confirm Server running (select Start Server if stopped), then Open Horizon Manager.
2. In Fleet View, confirm the aircraft returns to Active, and re-establish the UDP connection in the GCS application (127.0.0.1 : 14550) as soon as safely possible.
3. While the server is down, BLOS command routing is unavailable. Rely on the aircraft’s autonomous failsafe (e.g., RTL) until the link is restored.