# 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%2FAnybm9eS0ixPeTjgdHnz%2Fimage.png?alt=media&#x26;token=4aa02eda-46c0-4424-8374-0d9aa9971bfd" 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%2FATGMSaTYmdSTMkYxRYyL%2Fcezx..jpg?alt=media&#x26;token=668f1d10-1865-4655-a6ad-0e03e129105b" alt=""><figcaption></figcaption></figure>

3.3.3.Tight the batteries.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2FVZp7IhefSWrWeaT9Wtfg%2Fimage.png?alt=media&#x26;token=a7c54f62-6212-4a3e-8686-5cb819cf7435" alt=""><figcaption></figcaption></figure>