Went into RTL and no way to get out, crash!

I have a quad with 3.1.2 and had a surprise today. What happened. I was flying just doing some big ovals in stable mode and then I heard the mission planner say it went into RTL and I could see I didn’t have control anymore. I switched to alt-hold then to stable but it just stayed in RTL. I don’t have a big enough space to auto land so when it went into landing mode I just had to stand back as it came near my launch point and crashed into the house. Very lucky nobody was hurt and I only broke two props. It was upside down and I don’t even remember if they props were still spinning. Auto crash detection probably stopped the props but I was too much in a hurry to unplug the battery so I didn’t notice if the props stopped or not.

I tried to look at the TLOG but it seems a bit different than the PC version of MP. I’m using APM Planner 2.0 on mac. copter.ardupilot.com/wiki/common … etry-logs/

Want to understand what happened before I take this up again. It feels like it lost radio contact but not sure why that happened and why it never regained. I was always in close contact with it. Not far at all and even when it went into auto land after RTL I tried switching modes to regain control. Very dangerous but if it was responding to a radio loss fail-safe then I can see that there are very few options to avoid what happened. I just don’t have a big enough level area to launch from.

I just plugged in the battery after the crash and radio contact was fine so it seems the rx/tx is functioning.

Hopefully the logs tell the story! I’m just including the TLOG. I downloaded the data flash logs but most of them say 4 bytes and I’m not sure which one it would be. Oldest one is 730kb, next is 1.4MB and the rest are 4 bytes.

This is interesting, I have never had a tlog that I couldn’t open. Maybe include those dataflash logs?

Here are the last few. It’s hard to tell what is what on the log files because when it downloads them they all basically get the same date. Maybe inside they show the real flight date but it would be nice if the file name gave a hint also. If it’s not one of these I can upload a few before it but they are all mostly 4 bytes which seems much too small.

4 bytes means that the log contains 4 characters. Not useful… It is odd that I can’t read the tlog.

Switching modes is supposed to bring it out of the failsafe RTL, but if you franticly bang on the mode switch too quickly (as I have done before) the debouncing can prevent it from switching at all.

I’m starting to wonder if my Tx shut off. I’m using a 3S in it but noticed one cell is weakening. I’m using a spare now and haven’t been able to repeat the problem. I did turn the tx off and back on but in the panic didn’t notice if it actually came on. If that is the case, then it must have went flat very quickly because I didn’t get any battery warning beeps.