# Fell out from Mission to RTL and then to Stabilized

**URL:** <https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768>\
**Category:** Flight Testing & Log Analysis\
**Created:** [July 3, 2019, 3:35pm UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768 "2019-07-03T15:35:26Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![kpetrykin](https://discuss.px4.io/user_avatar/discuss.px4.io/kpetrykin/32/4110_2.png) [@kpetrykin](https://discuss.px4.io/u/kpetrykin)\
**Post date:** [July 3, 2019, 3:35pm UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/1 "2019-07-03T15:35:26Z")

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Hello!

We have two flights on our quadrocopter with strange and unsafe behaivour:

1. Mission started, copter took off to 60 meters, flew a little, then fell out to RTL for a few milliseconds and then to Stabilized (mode trigger on the RC was in this state at this moment). No any messages about erros arrived and no watchdogs also. Log: [https://logs.px4.io/plot\_app?log=c5d705ee-7945-4efa-9b87-63df59e93b8c](https://logs.px4.io/plot_app?log=c5d705ee-7945-4efa-9b87-63df59e93b8c)
2. The second mission was quite long, and suddenly copeter fell out into Althold (was on RC trigger at the moment). Again, no any messages or watchdogs. Log: [https://logs.px4.io/plot\_app?log=f0b213a0-f324-4288-8f4e-e30625758f74](https://logs.px4.io/plot_app?log=f0b213a0-f324-4288-8f4e-e30625758f74)

It may look like position lost failsafe, but when we have it in another times, we have a error messages, watchdogs and other signs in logs.

So, my main question is: in what cases the mission could fall into RTL and/or into rc-controll?

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**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [July 4, 2019, 8:11am UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/2 "2019-07-04T08:11:03Z")

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Just a guess: have you made sure that RC failsafe works properly? So e.g. when you switch off your RC does it detect it and say “RC lost” in QGC? My guess is that your RC receiver sets “failsafe values” when RC is lost which means the mode switch goes to stabilized, and throttle to low.

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**Author:** ![kpetrykin](https://discuss.px4.io/user_avatar/discuss.px4.io/kpetrykin/32/4110_2.png) [@kpetrykin](https://discuss.px4.io/u/kpetrykin)\
**Post date:** [July 4, 2019, 10:31am UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/3 "2019-07-04T10:31:35Z")

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I dive into logs and there’s no any failsafe flags there (red line is mode switching, others are different fail checks and they are all in zero)

 ![image](https://discuss.px4.io/uploads/default/original/2X/a/a869a24b3c1887bda7d8c492c95ac2f8308f4c79.png)  
 ![image](https://discuss.px4.io/uploads/default/original/2X/d/d191baac1acd9e2afc61b8cab2ef5a3ecc5cc7b6.png)

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<div class="post-metadata">

**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [July 4, 2019, 12:54pm UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/4 "2019-07-04T12:54:32Z")

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It would not be a failsafe in PX4, only in the receiver.

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<div class="post-metadata">

**Author:** ![kpetrykin](https://discuss.px4.io/user_avatar/discuss.px4.io/kpetrykin/32/4110_2.png) [@kpetrykin](https://discuss.px4.io/u/kpetrykin)\
**Post date:** [July 4, 2019, 2:35pm UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/5 "2019-07-04T14:35:55Z")

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Failsafe in the receiver? How should it work? “Trigger” an RTL trigger?

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<div class="post-metadata">

**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [July 8, 2019, 6:42am UTC](https://discuss.px4.io/t/fell-out-from-mission-to-rtl-and-then-to-stabilized/11768/6 "2019-07-08T06:42:03Z")

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If a receiver doesn’t receive a signal anymore, it either sets all channels to a certain value to indicate “failsafe” or it stops outputting a signal altogether.

For the latter case Pixhawk will detect that it lost RC but for the former it might not unless it is specifically configured to detect something like throttle low (see [https://dev.px4.io/en/advanced/parameter\_reference.html#RC\_FAILS\_THR](https://dev.px4.io/en/advanced/parameter_reference.html#RC_FAILS_THR)).
