Emergency landing tumbled crash? -- inav 6.1.1

[lida2003]

There are quite a lot of discussions about my crash in What will happen, when RC & GPS signal lost? -- inav 6.1.1 #9167

And Thanks for @Jetrell @breadoven patience , I think I have got much more info than before.

Due to our discussion about what will happen in emergency landing when fail throttle set to 1000 with airmode enabled? #9181, I think it'll be really not that easy to talk about this crash, as:

1. airmode seems to keep the attitude even if zero throttle
2. old doc says it'll be a supprise when failsafe_throttle = 1000 ( what I think it should probably write before airmode is implemented )
3. my crash, the quad is tumbled NOT attitude hold drop

So I decided to do an emergency landing test.

And It crashed, crashed, crashed!!!

Preset:

• failsafe_throttle = 1150
• disable GPS in gps tab
• RC channel trigger failsafe, which set to LAND

PS: detailed steps, please consult: https://blog.csdn.net/lida2003/article/details/131849539

Result:

Video: https://www.bilibili.com/video/BV1tu411V7JY?p=1
Log: blackbox_log_2023-07-21_070855.TXT

I'm NOT sure about exact order of the crash. But it seems has something to do with gyro and logic.

1. failsafe switch from althold
2. throttle reset to 0
3. gyro suddenly enlarged from ~1 to ~35
4. gyro further enlarged (out of range?????)
5. throttle adjusted to ~57% ???? try to save the quad???
6. gyro dead????? (Maybe on the ground as it's only about 1meter high for test.)
7. Now it's a mess

10. I wanna fly back to where I was, it flipped when take off. And all gyro data is zero.
    

Any ideas, please kindly let me know!

[breadoven]

This looks like the same issue as #8950.

The Emergency Landing starts at 00:44:235. The same issue as above happens at 00:44:288, Attitude values drop to 0, PIDS go crazy ... although the motor outputs look wrong even before that.

Moving to issues and flagging as a bug.

[lida2003]

@breadoven I have read #8950

It's closed by @fermiums22, but I didn't get the point of "Inav 6.1.0 Landing after RTH work is good". Maybe @fermiums22 was using RTH to land!

What if in my case (gps glitch), oh no~~~

Two issues have a similar data trend(just forget about vibration of my quad):

It was found in the log that the gyro raw data is inconsistent with gyro filtered data in the same situation(#8950 & #9184), which you (@breadoven ) have mentioned data consistency in #8950

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further discussion on #9184