# 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%2FRyYTbnsbN7O9P3ffNtkB%2Fimage.png?alt=media&#x26;token=aec54d83-9a28-4a0e-abf7-021ddb7effaa" 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%2Fo5tmaVQlCyCQuOWRr4jS%2Fimage.png?alt=media&#x26;token=cb12b413-aef6-49a4-8ae0-22ea133cbc81" 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%2FoajDoJz91go3YRBwjEuD%2Fimage.png?alt=media&#x26;token=46760582-d25f-47ff-b8b1-be89f506c2da" alt=""><figcaption></figcaption></figure>