VTOL Troubleshooting Workflows
Use symptom-led diagnostic trees to decide what to verify first, what stays props-off, and what not to tune blindly.
These workflows prioritize orientation, output ownership, geometry, transition behavior, and sensor trust before speculative parameter changes.
Forward tilt on takeoff
Do This First (Props Off)
- Confirm AHRS orientation and wrong-way correction direction.
- Verify tilt-servo neutral geometry and travel direction.
- Check which outputs actually own hover motors, tilt servos, and forward thrust.
Do Not Do This (Blind Tuning)
- Do not raise gains to fight a geometry or reversal fault.
- Do not assume the reference file can be copied into a different airframe.
- Do not refly only to “see what it does” after wrong-way behavior.
Won’t hover or drifts immediately out of authority
Do This First (Props Off)
- Verify motor order, spin direction, and output mapping.
- Confirm the correct frame assumptions and VTOL enablement lanes.
- Inspect center of gravity and neutral tilt geometry before another retest.
Do Not Do This (Blind Tuning)
- Do not chase hover instability with PID changes before the actuator map is proven.
- Do not treat a missing Q_ENABLE or wrong output ownership as a tune issue.
- Do not mix bench findings with undocumented field changes.
Bad transition or fixed-wing handoff instability
Do This First (Props Off)
- Confirm hover mode is already stable before transition work.
- Review tilt schedule, forward-thrust ownership, and airspeed assumptions.
- Check pitch assist, transition thresholds, and whether the airframe can actually meet them.
Do Not Do This (Blind Tuning)
- Do not lower thresholds until you know the aircraft can produce the required geometry and thrust.
- Do not interpret every transition upset as a gain problem.
- Do not skip short logged retests between changes.
Yaw spin, wrong-way correction, or sensor-trust concerns
Do This First (Props Off)
- Validate heading, compass orientation, GPS trust, and EKF health.
- Check servo direction, differential thrust assumptions, and rudder ownership.
- Confirm failsafe actions will not worsen the state if RC or navigation trust is lost.
Do Not Do This (Blind Tuning)
- Do not ignore sensor warnings because the aircraft “usually flies.”
- Do not compensate for wrong-way correction with trim or gain changes.
- Do not continue testing after repeated unexplained yaw authority loss.
Use the file-backed path before another launch
When the symptom tree narrows the likely fault lane, move into a parameter analysis, a direct comparison, or an expert review with the relevant files and evidence in hand.