# COM\_POSCTL\_NAVL does not work as said in Position (GNSS) Loss failsafe documentation (v1.16)

**URL:** <https://discuss.px4.io/t/com-posctl-navl-does-not-work-as-said-in-position-gnss-loss-failsafe-documentation-v1-16/48963>\
**Category:** PX4 Autopilot\
**Created:** [May 13, 2026, 6:07am UTC](https://discuss.px4.io/t/com-posctl-navl-does-not-work-as-said-in-position-gnss-loss-failsafe-documentation-v1-16/48963 "2026-05-13T06:07:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![SoRage](https://discuss.px4.io/user_avatar/discuss.px4.io/sorage/32/18408_2.png) [@SoRage](https://discuss.px4.io/u/SoRage)\
**Post date:** [May 13, 2026, 6:07am UTC](https://discuss.px4.io/t/com-posctl-navl-does-not-work-as-said-in-position-gnss-loss-failsafe-documentation-v1-16/48963/1 "2026-05-13T06:07:30Z")

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I am trying to run HIL simulations on v1.16.0 with Pixhawk Cube orange+. I am using a Simulink fixed wing model for flight dynamics and sensor models. While trying to simulate the **Position (GNSS) Loss Failsafe** I just switched off the GNSS data being sent to Cube mid flight.  
According to the Parameter description and failsafe documentation the aircraft should switch to either Altitude/ Stabilised mode if the parameter **COM\_POSCTL\_NAVL** is set to 0 based on the altitude estimate availability. But each time I trigger GNSS failure it directly enters Land mode.  
I also experimented with **COM\_POS\_LOW\_EPH** and **COM\_POS\_LOW\_ACT**. When I fail GNSS and the position accuracy falls below **COM\_POS\_LOW\_EPH** it rightfully triggers the failsafe action mentioned in **COM\_POS\_LOW\_ACT.** Also when accuracy falls below **COM\_POS\_FS\_EPH** it immediately triggers Land.  
But I never see effect of **COM\_POSCTL\_NAVL** on GNSS failure. Am I missing something or can somebody explain what exactly is the failsafe logic here?

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**Author:** ![system](https://discuss.px4.io/uploads/default/original/3X/7/3/73ce918bdcd64854de904f0c8d9ab70ca9723f2a.png) [@system](https://discuss.px4.io/u/system)\
**Post date:** [August 11, 2026, 6:07am UTC](https://discuss.px4.io/t/com-posctl-navl-does-not-work-as-said-in-position-gnss-loss-failsafe-documentation-v1-16/48963/2 "2026-08-11T06:07:33Z")

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