# \[VTOL SITL\] Issue with offboard\_velocity example

**URL:** <https://discuss.px4.io/t/vtol-sitl-issue-with-offboard-velocity-example/12972>\
**Category:** MAVSDK\
**Created:** [September 17, 2019, 2:59pm UTC](https://discuss.px4.io/t/vtol-sitl-issue-with-offboard-velocity-example/12972 "2019-09-17T14:59:16Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![TSt](https://discuss.px4.io/letter_avatar_proxy/v4/letter/t/f6c823/32.png) [@TSt](https://discuss.px4.io/u/TSt)\
**Post date:** [September 17, 2019, 2:59pm UTC](https://discuss.px4.io/t/vtol-sitl-issue-with-offboard-velocity-example/12972/1 "2019-09-17T14:59:16Z")

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Hi,

I just installed MAVSDK (built from source) and tried the offboard\_velocity example (my first steps with the SDK). Something is broken for the VTOL simulation (on the current master branch for PX4 and current developer branch for MAVSDK) :

[https://logs.px4.io/plot\_app?log=c1060b4e-b930-43f2-a3ee-d5ca5a41b686](https://logs.px4.io/plot_app?log=c1060b4e-b930-43f2-a3ee-d5ca5a41b686)

With the standard Gazebo model (Iris) the example works fine. And VTOL simulation works fine with the fly\_mission example.

What could be the reason for this problem and how to solve it?

Thanks for any help!