# How to Fix FPV Drone Drift in Angle and Horizon Mode
You arm your quad, take off in Angle mode, and it immediately drifts — pulling left, right, forward, or back without any stick input. This is frustrating, but it’s almost always fixable. This guide covers the step-by-step diagnosis and correction of drift in stabilized flight modes.
## Why Does My Drone Drift in Angle/Horizon Mode but Not Acro?
Angle and Horizon modes use the accelerometer to self-level. Acro mode only uses the gyroscope. Drift in stabilized modes almost always traces back to an accelerometer issue:
| Cause | Why It Happens |
|——-|—————|
| Accelerometer not calibrated | The FC thinks “level” is tilted |
| Trim values set on radio | Subtrim adds constant stick offset |
| FC not mounted level | Physical tilt relative to frame |
| CG (center of gravity) offset | Battery position pulls one direction |
| Stick endpoints not centered | Radio outputs non-zero at center stick |
| Motor/prop imbalance | Asymmetric thrust overwhelms leveling |
## Step-by-Step Drift Diagnosis
### Step 1: Check Your Radio Trims and Endpoints
This is the #1 cause of drift. In Betaflight Receiver tab:
1. Power on your radio and quad (props off!)
2. Watch the channel bars for Roll, Pitch, Yaw
3. With sticks centered, all should read **exactly 1500**
| Reading | Issue | Fix |
|———|——-|—–|
| 1495-1505 | Acceptable (±5 jitter) | Normal, move on |
| <1490 or >1510 | Trim or endpoint off | Adjust radio subtrim or Betaflight RX range |
| Jittering >±10 | Dirty potentiometer/gimbal | Clean or replace gimbal |
**Set the RC Deadband to 3-5** on Roll, Pitch, and Yaw in Betaflight to ignore minor center jitter.
### Step 2: Calibrate the Accelerometer
If your radio centers are perfect but you still drift:
1. Place the quad on a **truly level** surface (use a bubble level)
2. Go to Betaflight Setup tab
3. Click **Calibrate Accelerometer**
4. Wait for the 3D model to show level
**Critical**: The surface must match the flight controller’s mounting orientation. If your FC is rotated 90° or mounted upside down, the calibration surface must account for that.
### Step 3: Check FC Board Alignment
Go to Betaflight Setup tab. Tilt the quad:
| You Move | 3D Model Should | If Not |
|———-|—————-|——–|
| Nose down | Nose down | Board alignment wrong |
| Roll right | Roll right | Board alignment wrong |
| Yaw right | Yaw right | Board alignment wrong |
If the 3D model doesn’t match, go to Configuration tab and adjust **Board and Sensor Alignment**:
– Yaw Degrees: Usually 0, 90, 180, or 270
– Set the correct value, save, then recalibrate accelerometer
### Step 4: Physical Mounting and CG
| Check | Action |
|——-|——–|
| FC is flush with standoffs | Add washers if tilted |
| Standoffs are same height | Replace mismatched ones |
| Battery centered on top plate | Mark battery position with tape |
| No loose wires pulling FC | Secure all wiring |
### Step 5: Adjust the Accelerometer Trim
If all hardware checks pass but you still have a slight drift, use stick commands:
1. Arm the quad in Angle mode
2. Hover and note drift direction
3. Land, disarm
4. **Throttle up + right stick to correct drift**:
– Drifts forward → Throttle up + Pitch back (hold) until FC blinks
– Drifts right → Throttle up + Roll left (hold) until FC blinks
5. Test hover again
Each blink corresponds to one trim step. You can apply up to 20 steps.
## Recommended Flight Controller
A flight controller with a high-quality ICM-42688-P or BMI270 gyro/accel provides superior vibration rejection and drift stability. The **SpeedyBee F405 V4** features the BMI270 and is one of the most reliable FCs for drift-free Angle mode. Available at [uavmodel.com](https://uavmodel.com).
## Video: Fixing Betaflight Angle Mode Drift
## Quick Checklist
– [ ] Radio subtrims center at 1500 in Receiver tab
– [ ] RC Deadband set to 3-5
– [ ] Accelerometer calibrated on level surface
– [ ] Board alignment matches physical orientation
– [ ] FC mounted flat; battery centered
– [ ] Acc trim applied if slight drift remains
Drift in Angle mode is almost never a hardware defect — it’s a configuration issue. Work through these steps systematically and you’ll have a rock-steady hover every time.