# 3.3. CoG calibration

3.3.1. Put the batteries into the battery compartment.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2FmuOWBiuzmNpETHLUNaMO%2Fimage.png?alt=media&#x26;token=f661b1b0-ffcb-4312-839c-91add005ffa2" alt=""><figcaption></figcaption></figure>

3.3.2. Check the aircraft center of gravity.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2Fc413bqiaYKS82HfbfvfO%2Fimage.png?alt=media&#x26;token=dd0d6445-0e9e-4838-8605-1f5e494af5aa" alt=""><figcaption></figcaption></figure>

3.3.3.Tight the batteries.

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