Hello everyone, I am experiencing a critical arming failure on my fixed-wing aircraft running PX4 on a Cube Orange. The system is refusing to arm due to a persistent Airspeed sensor error, and I cannot override the issue, even with the highest safety bypass settings. **1. Hardware & Setup:** * **Flight Controller (FC):** Pixhawk Cube Orange * **Aircraft Type:** Fixed-Wing (SYS_AUTOSTART=2100) * **Firmware:** PX4 (Latest Stable Release) * **Radio:** FrSky Taranis X9D Plus * **GPS/Compass:** HR4 Module * **Telemetry:** RFD868x (connected via COM12 at 57600 baud) —
2. Core Problem & Symptoms The main issue is that the motor refuses to stop the fast beeping sound and twitches constantly (seyirme) when the aircraft is powered on and disarmed. This suggests a continuous signal instability or a hard arming lockout. **Addendum to Symptoms (Crucial Observation):** When the aircraft is powered on (and disarmed), the motor exhibits the following behavior immediately: * A **loud and rapid continuous beeping sound** is heard from the ESC/Motor. * The motor **twitches/jumps** quickly and repeatedly. — ### 3. Key Error Messages from QGroundControl Console The system is definitively locked out by the Airspeed issue: * `Critical: Preflight Fail: Airspeed invalid` * `Preflight Fail: Airspeed selector module down` ### 4. Troubleshooting Steps Taken (All Failed to Resolve Lockout) 1. **Radio Calibration:** Successfully completed. Fixed reversed Pitch channel (CH2) and adjusted PWM End Points on the Taranis to ensure correct 1000/2000 range for all main channels. 2. **Airspeed Physical Check:** Avionic technicians confirmed the silicone tubes are correctly connected (not reversed), but the sensor gives an erroneous high reading (e.g., 2100). Calibration attempts fail immediately. 3. **Safety Bypass 1 (Pre-Arm):** Set **`COM_PREARM_MODE`** to **Always (2)**. This *should* bypass all pre-arm checks, but the motor beeping/twitching persists after saving and rebooting the FC. 4. **Safety Bypass 2 (I/O Safety):** Checked/set **`CBRK_IO_SAFETY`** to **22027** to ensure safety switch functionality is completely disabled. 5. **Parameter Check:** Confirmed that neither `CBRK_AIRSPEED` nor `ARMING_CHECK` parameters are available in the QGC parameter list.
5. Question to the Community Since the ‘Always’ setting is ineffective and the system remains locked out, I suspect a deeper issue. * Is there a known low-level lock (possibly related to `Airspeed selector module down`) that overrides even the `COM_PREARM_MODE=Always` setting in PX4? * What is the best way to definitively disable the Airspeed check in PX4 when standard parameters are failing? * Could the continuous beeping and twitching (which indicates an unstable signal to the ESCs) be caused by the FC being stuck in a critical error loop that prevents a clean disarm signal? Thank you for your assistance.