Yesterday I had my biggest, worst and most scary crash with my 3DR Quad.
Our local firefighters had an open day for public and presented their equipment, did some presentations, they had a jumping castle for the kids, BBQ and beer for the bigger ones.
A friend of mine who is always acting as a spotter for me when doing video flights planned to do some aerial footage of the place and in a second flight film the firefighter team during a car rescue.
So I picked up my quad with full loaded batteries, pre checked everything in my office and went to the starting locations. Here I powered the quad up und waited to get a GPS lock. I didn't need the GPS, but I just wanted to make it absolutely right, because I would be flying over a crowded place.
So after 2 minutes of patience I had a stable GPS lock, made sure I had the right flying mode dialed in, in this case I used stabilize with simple mode, so I could concentrate on the flying location while my spotter would give me advises how to align the camera.
A quick spin up test, everything was fine, so I took of, stabilised the copter in mid air 2 meters from the ground for a couple of seconds and pulled the throttle up to get some height.
First position was reached (no mission, no fpv, just plain odd manual control) so I headed to the second position and yawed the copter 90 degrees to the left. After the yaw I felt the copter beginning to drift a little so I pushed him backwards towards me and reverted yaw so the copter looked away from me.
I wanted to fly back to me whitch meant backwards for the copter but the quad started to lean more and more forward. I had fully deflected the stick backwards, but the copter would not come back, ist slowly increased pitch for some reason.
Because of the kids and the people under the copter the only way to recover safely from this situation was to apply throttle and let the copter drift away over the firehouse, keeping it in the line of sight until I could be sure it was over the building towards free space and then shut the motors down.
The result: most important: nobody injured, for gods sake!!!
2 Motors broken
2 arms damaged
GPS unit destroyed
IMU shield defective
maybe more to come, I didn't disassemble and tested everything right now
I have absolutely no clue what happened! So any help in order to understand what went totaly wrong would help!
P.S.: Board Version 1.4, Quad with 850 motors, all settings to stock, Firmware version 2.7.1
First, let me say you were very conscientious. You moved your quad to a safe area. Just imagine if you'd have hit one or more people. You and likely 3DR would be opened up to huge liability lawsuits.
I use the following modes. Simple, stabalize, ACRO, RTL, auto, Alt Hold and Loiter. I built my frame based on the Arducopter. AC2217-9 motors, 18A ESCs, APM 2.0, Spektrum DX7s TX, Spektrum 7 channel RX and a Hyperion 4A Lipo and a small HD camera. Fully loaded it weighs 1468 grams. I can fly casually for about 8 minutes.
I realize people want to use their quads. People are buying these thinking they are toys that can be flown by unskilled pilots. The certainly aren't advertised as such. I flew RC planes 35 years ago. I got back into RC a couple of years ago with micro-copters to regain skill. I then moved to a blade mQX to get quad experience. Only then did I move to the much more dangerous larger motors, props and APM. In my opinion, 3 to 4 flights are not sufficient testing to have confidence in the quad. I fly with people around but I didn't do so until I'd flown about 30 flights. I'm now comfortable flying my quad within a foot of my person. Only I am in danger. I would not fly that close to anyone else ever. When I get a new quad, I'll do the same. I'm also not telling anyone where or how to fly their quads, that is up to them. However, don't blame the bits and bytes if someone gets hurt.
Saying everything was perfect shows a lack of understanding of what you are using. Even with deadly vehicles that have been around for decades, nothing is perfect. Last weekend there was a crash at a truck race. The truck, with a driver inside, veered into a crowd. There are airshows in which people in the crowd have been injured and killed. Does that mean we shouldn't use them around people? Of course not. We shouldn't be using them around people until we are confident in their behavior. Even with confidence, there will be failures and accidents.
I agree with you on bug notices and changes. The are there but you must dig to find them. I also feel the documentation is lacking. However, Chris has committed to fixing the documentation.
3DR doesn't have any liability in the mater. This was a pilot and/or software related failure, and 3DR does not make the software.
I agree with the rest of what you wrote. Despite best efforts, sometimes stuff happens.
If it could be proven that there was a bug or other defect in the hardware/software 3DR would have liability. There are many companies that have found this out the hard way. Many U.S. legislators and lawyers want gun companies held accountable for the crimes in which their products get used. We, the users of this product, should do all we can to limit this possible eventuality.
I'm not a lawyer but I've seen the cases before.
Remember that this community actually started as a bunch of like-minded enthusiasts discussing auto-pilots, and that Jordi and Chris found they could save people a few bucks if they went in together and ordered a few parts in batches and then custom built a few boards, and eventually 3DR was born.
The software is the responsibility of the open-source community and is contributed to by everyone.
Liability in this community setting would be difficult to prove.
marc, I agree we shouldn't discuss it in this thread. I just brought it up as something to think about. However, whistling past the graveyard does not make it go away.
Actually, looking at Jenkins, most of the testing has not completed successfully for around 3 months. That means that all of your recent releases went out basically untested. ArduCopter has some recent test runs (good for them) and there's an autotest for something called "skel", but the rest aren't even building.
Are the test procedures documented somewhere?
Can someone describe how sensor data in integrated in ArduPilot? This craft came down due to a poorly estimated yaw value, but this condition should have been obvious to the software. There was enough sensor data to prevent this:
A properly filtered IMU would have quickly ignored the anomalous compass data.
At the very least, the AP should have detected that the compass reading was not nominal at launch and refused to arm the motors. I understand that in-flight failsafe may not be feasible in ArduCopter, but keeping this craft on the ground would have prevented this loss and many others.
First, you flew over people with, in my opinion, an untested craft. The following comment you made shows you weren't confident flying this craft yet. “But I didn't dare to touch anything else on the transmitter than the sicks.” Another comment shows you weren't in the correct frame of mind. “you are absolutely right that the firmware is still experimental. The only person I can blame is myself, that I forgot about that“ The “everything was perfect” comment is just another indicator of the frame of mind you were in.
I'm really not judging you. You did an excellent job of avoiding the people, even at the cost of your craft. As I said, I am not telling anyone how, when or where to fly their crafts. The main reason I commented was that you were trying to blame “bits and bytes” if someone had been hurt. I was just pointing out that the bits and bytes can't control where people use them.