# My Sentinel crashed during simple missions with "Failsafe activated, triggering descend"

Source: https://forum.modalai.com/topic/3923/my-sentinel-crashed-during-simple-missions-with-failsafe-activated-triggering-descend
Category: Development Drones (https://forum.modalai.com/category/44/development-drones)
Tags: sentinel
Posted: 2024-11-11 19:11:55 UTC by Jerry Lin
Replies: 1 · Views: 992

## Jerry Lin · 2024-11-11 19:11:55 UTC

Hi, here is the full message![Screenshot 2024-11-07 at 4.28.28 PM.png](https://forum.modalai.com/assets/uploads/files/1731352015125-screenshot-2024-11-07-at-4.28.28-pm.png).

Also sometimes the following was encountered: ![Screenshot 2024-11-07 at 5.13.00 PM.png](https://forum.modalai.com/assets/uploads/files/1731352054379-screenshot-2024-11-07-at-5.13.00-pm.png).

When I tried few simple missions, not sure why this happened only at certain points or certain directions? Also not sure why both local and global position estimates failed at the same time?

## Reply by Jerry Lin · 2024-11-11 22:06:15 UTC

I suspected probably it is because of the fused local position by vision and searched in parameter. It sounds `EKF2_GPS_CTRL` is probably relevant. So, I set it to be 0 from 7. After trying that, my outdoor missions were all smooth without any accident. 

I then set it back to 7 and tried flying in position mode. This error happened again and with altitude mode was forced.

So, anybody here know how to fix the problematic local position estimate? This is an AI drone and it shouldn't perform worse than drones without any vision.