"Maybe this will help:
Re: [ardupilot] Copter: add support for mavlink do-sonar-test (#1081) (https://github.com/diydrones/ardupilot/issues/1081)
Randy Mackay has told me that "AC3.2-rc2 will report the sonar distance to the ground station so then MP…"
I had the same problem with wind and I resolved it after an Autotune sesion. . Most PIDs were increased.
Please, find here-attached two images of my config before and after Autotune.
Now it works much better facing to wind…"
"Thanks Tridge for your comments. Yes, I know that FBWA is not an altitude hold mode and that is precisely the most confusing issue of my crash (and maybe one of the reasons because I took so long to react to that problem with altitude). I will…"
"I crashed my plane two days ago because a problem that reminds me to one that is described in this post, although I was flying with APM 2.5 (not Pixhawk). Firmware ArduPlane 3.0.2
I don't really know why my plane became to pitch down while I was…"
First of all, check your antennas (inside the rubber cover, if possible) and their connectors (if you haven't done it yet). You have very low noise levels but your rssi are not so high for two modules been so close. And 150 m is a short…"
I also suffered an attack like yours but in my case it was probably caused by a spike that somehow got through to the signal wires connected to the ESC while I was handling a wire connected to APM module, as @Randy suggested. You can see…"
"Too much problems with base noise using RDF900 as ground radio.Dear Seppo ,I have just bought a RDF900 for use it as ground radio and my first tests are very dissapointing because of what I think that is an unacceptable local RSSI noise. Although…"
"Thanks to all for your comments!@Randy, my ESC are DJI 30A opto. In fact, I installed them because a lot of people trust on them. In my first setup I used blue F30A HK reflashed with SimonK but one of them got burned and also its motor (in the same…"
I have suffered a little accident at home with my quad when motors suddenly turned on while it was disarmed! A very strange behaviour that I still don't understand even after review the tlog and look for something like that in the diydrone forum.…
I am still doing more research about my problems with 2.76 and I have found a most tricky problem that could explain what I posted before. I lost a lot of parameters when I upgrade from 2.74 to 2.76! Concretely the following ones…"