USB data connection

Overview

PC cannot see drone — charge-only cable or driver.

DJI OcuSync/Lightbridge, ExpressLRS, Crossfire, analogue 5.8 GHz VTX, Walksnail/HDZero.

Symptoms

Typical "USB data connection" signs in flight, app or OSD:

• Device not recognized
• Charge only
• Betaflight Configurator timeout
• Log RSSI/LQ during flight — where link drops.

Common causes

Before replacing parts, rule out software, mechanical and environmental causes:

• Charge-only USB cable
• Wrong USB port on controller
• Driver missing (Windows)

Tools needed

Prepare before diagnostics — saves time in the field:

• Two data-capable USB cables
• ELRS/Betaflight Configurator
• Antenna and u.FL/MMCX checker

Step-by-step fix

Work safely: battery off when working on ESC/motors; props removed; after repair — VLOS test flight.

• Use data-capable USB cable.
• DJI: direct aircraft USB, not RC only.
• Install STM/VCP drivers for FPV FC.

Additional diagnostics

Log RSSI/LQ during flight — where link drops.

Ground failsafe test before each session.

Channel scan — verify clean channel away from Wi-Fi.

When to contact service

If any of the following apply — do not fly and contact authorised service:

• RX/VTX antenna physically damaged after crash.
• Link fails even at 5 m — hardware replacement.
• DJI RC screen won't boot — service.

Prevention

Prevention reduces failure risk and supports EASA Open / VLOS compliance:

• Label data cables in field kit

Frequently asked questions

Is it safe to fly with "USB data connection"?

No if the fault affects navigation, power, ESC or link. Fix on the ground first, then conduct a VLOS test flight in open area.

How long does diagnosis take?

Most “USB data connection” cases — 15–45 min on the ground. Complex ones (firmware, hardware) may need 1–2 h and service.

Must I register repair with the NAA?

No mandatory repair registration, but a maintenance log is recommended for commercial operations.