Worst Crash ever, Log analysis needed!
Hey folks!
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!
Greets
Marc
P.S.: Board Version 1.4, Quad with 850 motors, all settings to stock, Firmware version 2.7.1
- Attachments:
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2012-09-03 14-17 9.kmz, 20 KB -
2012-09-03 14-17 9.log, 141 KB
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2012-09-03 14-17 9.log.gpx, 46 KB
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Replies to This Discussion
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Permalink Reply by Carl La France on -
You still seem shaken! breathe in breath out .It is unfortunate you had to kill the copter you did the right thing under the situation I am not really a Quad guy but there should be something like a retractable dog's leash and weight say 20 feet long that could be clipped to the bottom of the copters on fire up when every thing is flying and working properly unhook it and go fly. I notice a pattern it is usually on start up or shortly after they click on the "amp"they wander off. Do you think a bunch of people in the crowd using cell phones might have had some thing to do with it ?On the telephone pole out side the fire station here there is a high frequency signal devise emitting a signal 24/7 if there is a call the fire fighters push a button and all the traffic lights go green . you might have got jammed from a signal from the fire department it self? Just throwing it out there?If you get any crap from this there is only one way to take it. Face it head on deal with it then move ahead.Try and have a nice day!
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Permalink Reply by marc.kulhavy on -
Hey Monroe,
I will post a full set of pictures of the copter, assembled and disassembled as well, the logs are attached in the original post.
I am not sure if we will find the real reason because the imu seems to be damaged due to the crash. Or it was the reason of the crash. Whatever, I will check every single piece of the copter.
Marc
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Permalink Reply by Carl La France on
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An other reason I would say a form of "Jammed" you made it to the first marker Ok on manual
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DeveloperPermalink Reply by R_Lefebvre on -
I haven't looked at the logs yet, but I just wanted to say you did the exact correct thing as a pilot, IMO. Instead of shutting it down and having it crash into people, you throttled up, got it away from people, then killed it.
This is why I keep saying over and over that there should not be a "watchdog" or "killswitch" which simply kills it as soon as anything goes wrong.
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Permalink Reply by Kevin Brown on -
what happened to the video ?
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Permalink Reply by marc.kulhavy on
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Being uploaded right now, should be reade in a couple of minutes.
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Permalink Reply by marc.kulhavy on
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A killswitch would have lead to a fatal ending. It should always be in the decision of the pilot how to recover from a dangerous situation. In this case, the only decision was to keep the people and kids away from serious injury. I still get a cold shiver when I think of what could have happened.
Marc
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Permalink Reply by Carl La France on
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@R Lefebre How does the kill switch kill the copter? automatically over the crowd as soon as some thing goes wrong? or does the pilot operate the kill switch? I think I know what you mean it is just the way it was worded Have a Good Day!
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DeveloperPermalink Reply by R_Lefebvre on -
Carl, some people have been demanding a failsafe system, onboard the APM, which automatically kills the copter as soon as anything goes wrong, with no input from the pilot. I am a strong opponent to this idea. In this case, it might have led to the craft crashing into the crowd. This is why people operating these systems need to be skilled pilots, and the system is an aid to make things safer. The system should not be used by people with no piloting skills, making them think they can fly, over crowds, etc.
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Permalink Reply by Carl La France on
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@R Lefebvre That is scary "the Amp "senses a problem and automatically shuts things down on it's own with no pilot input . And people are demanding it ? I am with you on this one and this is an example of the reason why it should not be implemented . There are not to many successful landings with"God" flying the plane. I remember just one time Back in the 1980.s cessna was flying along The edge of the rocky mountains at night they were 75 miles from the nearest community There was a pilot a minister and 2 passengers they were at 8000 feet and had an engine failure they set up a glide of 200 feet a minute let go of the controls and began to pray. the plane came down in a slew(avalanche takes the trees down) nocked the wings off but other wise they were all right a helicopter picked them up the next day they figured it was the only clear spot without trees in 15 miles on the accident report they wrote 'God"was flying the plane.
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Permalink Reply by Drone Savant on -
I may suggest that this could be related to what causes a case of "the leans". What you said with regard to "but the quad started to lean more and more forward. I had fully deflected the stick backwards, but the copter would not come back" is strikingly similar to previously documented symptoms that are described here http://diydronesafety.com/general-chatter/18.htm. I am sure whomever examines the logs will have a solid explanation.
R_Lefebvre I think you misunderstand the "When something goes wrong" aspect of the desire for a properly implemented watchdog. I won't hijack the thread to explain it but I think you may want to go back and reexamine some of those requests/issues/demands. http://code.google.com/p/arducopter/issues/detail?id=237 for example speaks of the APM code freezing specifically... not just "something going wrong". There is a big difference between code lockup and pilot error / environmental influences. Failsafe logic obviously has to be well though out. I'm not aware of anyone asking for a flight termination at every hint of an issue unless it is something that the user *wants* to do.
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Permalink Reply by Drone Savant on
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Look guys... if you don't understand how a watchdog works that is fine, just step up and say it. If someone is going to attempt to educate a user here on how failsafes work and attempt to put a slanted spin on it, expect me to chime in.
Incorrect information is not safe for anyone involved. Developers convincing other developers or end users that certain types of failsafes are not possible or are only able to be implemented with flawed logic is not safe either.
Not trying to steal your thread... simply trying to correct incorrect information.
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