Welcome to the APM:Copter forum!
Before posting, please check the copter wiki, review the firmware release notes in the subforum, and search this subforum for existing answers to your question. Help avoid duplicate threads by finding other operators with the same issue.
When formulating your post, use a descriptive title such as “Copter altitude not stable in alt hold mode” (not “HELP!” or “Problem”).
Please include the following information to help diagnose your query:
[ul][li]Describe the problem you are having. What is the expected verses the observed behavior?[/li]
[li]Provide hardware information such as the brand and version of your autopilot, GPS, radio, and compass, as well as any other pertinent details about your setup.[/li]
[li]What version of the APM:Copter firmware version are you running?[/li]
[li]For flight issues, provide your dataflash log. Click here for instructions on retrieving a dataflash log.[/li][/ul]