My name is Jeremy, and this is my first post. I am totally new to APM, GPS flight controllers, and to this forum. I would like to apologize for not having a genuine 3DR APM 2.6, and being that I have a clone 2.8 version I hope that this doesn’t mean I won’t be able to get help here. I honestly had no idea that 2.8 was not a genuine 3DR product when I purchased it. Forgive me.
I am hoping to get some help in understanding how to read logs and find a cause for my recent catastrophic crash. I can pull up the logs but it seems like some of what data would be useful either only has a dead flat line for the duration of the flight, or there isn’t data for that parameter. I’m hoping someone can make sense of my data file.
I’m trying to not be too devastated by this crash, as I have had my share of quadcopter and heli crashes, so I’ve come to expect these things and I’m just hoping to avoid whatever caused this one in the future. That being said, this one is more disappointing being that with the 4 successful flights I had prior to this crash, I hadn’t even gotten through a successful tuning period to even begin to see the capabilities of this flight controller before I’m in the process of rebuilding from a crash! Ugh…
Onto the crash.
(X525 Quadcopter with extended arms to 680mm with Sunnysky 2216 800kv and APC 12x45 props, Boscam VTX, eBay gimbal, and GoPro on board)
Took off in stabilized mode, selected Alt Hold mode within a few seconds, gained approx 25’ of altitude, then selected Autotune. It began its process and did so for a couple of minutes. The inputs it was making were rather drastic I noticed, quite pronounced. I brought it back near the starting point, at about 25’ probably 3 times, then on the 4th time of it being some distance away I began the input to steer it back once again. At 2:34 into the flight it went completely inverted and fell from about 25 feet. Once it was inverted it didn’t seem to roll any more, just went flat upside down and fell. But I only had about 2 seconds to watch it happen so that’s only what I can remember.
I am suspicious of my on board GoPro possibly causing some interference. Here’s why: On my previous catastrophic crash (same airframe, different motors and KK2.1.1 flight controller), which put the whole craft into a shallow pond, my gimbal mounted GoPro 3 Black was recording video just fine, then at the moment it fell from the sky (in essentially the same exact manner) the video stopped recording suddenly. The same thing is noticed on this crash; rather than having footage of the descent and impact the video just stops the instant before the sudden change in attitude.
Could it be that the GoPro is putting out some sort of signal that just sends these flight controllers out of control? I mean, I, and many others run these tiny cameras on miniquads all the time and I’m not aware of this being a known issue.
Anyway, hopefully someone can decipher the log and see if anything raises any flags. I mean this was during Autotune, but I can’t seem to find any Autotune messages. All the data I’ve been able to graph looks pretty consistent all the way up to the stop point. But that is also puzzling because the APM was still powered on until I unplugged it, some 20 seconds after the impact… They don’t show any sudden change in ATT or ALT from what I can tell. But that’s what I’m probably not understanding in reading the logs.
And the one question I’d ask directly about the log is: does the “time mark” along the bottom of the graph represent a physical time, or what do those numbers mean? All my data ends at one specific point, I’m assuming that’s when I unplug it.
Once home I downloaded the log file and checked to see if the GPS could still see satellites, mostly being concerned because the GPS antenna was the first point of impact. Although the mast was destroyed and the GPS case scratched up a bit it still found 8 satellites under my car port, so that’s a good sign. I think the APM is okay, being that the GPS antenna and my motor nuts took the brunt of the impact, but I’ll have to get into it again to see if the sensor are all working properly.
Thanks for your help. Sorry for the lengthy post. Hope to get to the bottom of this one or at least further my education on this whole Mission Planner and APM system.