# I can't find the reason of crash

**URL:** <https://discuss.px4.io/t/i-cant-find-the-reason-of-crash/24367>\
**Category:** PX4 Autopilot\
**Created:** [September 29, 2021, 3:34am UTC](https://discuss.px4.io/t/i-cant-find-the-reason-of-crash/24367 "2021-09-29T03:34:08Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![wuyong.yi](https://discuss.px4.io/letter_avatar_proxy/v4/letter/w/e47774/32.png) [@wuyong.yi](https://discuss.px4.io/u/wuyong.yi)\
**Post date:** [September 29, 2021, 3:34am UTC](https://discuss.px4.io/t/i-cant-find-the-reason-of-crash/24367/1 "2021-09-29T03:34:08Z")

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[crash log](https://logs.px4.io/plot_app?log=c698af94-7edc-4429-acbe-a6fbebf658f7)

Hi there,

I tried to control the drone in offboard mode.  
As you can see, my drone was flight the position mode in startup. In this situation, it did not fix the position exactly. But I just did the offboard mode. A few seconds or minutes, it worked not bad. But my computer or other device had some problem, so changed the flight mode to positon, and tried to move the drone to land position.

Drone did not work perfectly. So again, changed the altitude mode and tried to land. For a few seconds, flight was unstable. Hit the wall and crash.

I couldn’t find problem why drone was unstable. It looks magnetometer is not perfect. But I think in altitude mode, it does not affect critical issue.

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<div class="post-metadata">

**Author:** ![farhang](https://discuss.px4.io/user_avatar/discuss.px4.io/farhang/32/17881_2.png) [@farhang](https://discuss.px4.io/u/farhang)\
**Post date:** [September 29, 2021, 8:50am UTC](https://discuss.px4.io/t/i-cant-find-the-reason-of-crash/24367/2 "2021-09-29T08:50:51Z")

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Sharing a log may help.

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<div class="post-metadata">

**Author:** ![wuyong.yi](https://discuss.px4.io/letter_avatar_proxy/v4/letter/w/e47774/32.png) [@wuyong.yi](https://discuss.px4.io/u/wuyong.yi)\
**Post date:** [September 30, 2021, 5:27am UTC](https://discuss.px4.io/t/i-cant-find-the-reason-of-crash/24367/3 "2021-09-30T05:27:03Z")

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Top of my text, you can see the link of log.

[https://logs.px4.io/plot\_app?log=c698af94-7edc-4429-acbe-a6fbebf658f7](https://logs.px4.io/plot_app?log=c698af94-7edc-4429-acbe-a6fbebf658f7)