Q450 4.0.5 Crash


I finally got my quad working nicely in the configuration I wanted, so I sent it out auto flight.
A minute after launch (after it had passed the first waypoint) it dropped out of the sky like a rock and smashed into several pieces.

I followed the instructions here in an attempt to diagnose the problem. The fact that Roll did not match DesRoll, and Pitch did not match DesPitch indicated to me that there was a mechanical problem.

However, when I hooked up and tested the motors after the crash they seemed to work fine.

The specs are as follows:
Frame: Q450
Motors: Emax 2216 (810Kv)
Battery: 5000MaH 4S
Controller: Pixhawk (clone)
Firmware: Arducopter 4.0.3

Here is the auto-analysis of the last flight:

Log File C:\Users\shane\AppData\Local\Temp\tmpCB22.tmp.log
Size (kb) 4668.23828125
No of lines 54875
Duration 0:02:37
Vehicletype ArduCopter
Firmware Version V4.0.5
Firmware Hash 3f6b43e3
Hardware Type
Free Mem 0
Skipped Lines 0
Test: Autotune = UNKNOWN - No ATUN log data
Test: Brownout = GOOD -
Test: Compass = FAIL - Large change in mag_field (45.19%)
Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = FAIL - ERRs found: FLT_MODE GPS_GLITCH
Test: GPS = UNKNOWN - join() takes exactly one argument (2 given)
Test: IMU Mismatch = GOOD - (Mismatch: 0.74, WARN: 0.75, FAIL: 1.50)
Test: Motor Balance = UNKNOWN - tuple index out of range
Test: NaNs = FAIL - Found NaN in CTUN.DSAlt
Test: OpticalFlow = FAIL - FAIL: no optical flow data
Test: Parameters = FAIL - ‘MAG_ENABLE’ not found
Test: PM = GOOD -
Test: Pitch/Roll = UNKNOWN - ‘BarAlt’
Test: Thrust = GOOD -
Test: VCC = UNKNOWN - No CURR log data

The logs from the last flight can be found here:

I’m not sure what would cause such a sudden, catastrophic, failure.
Could this be ESC sync failure?

Can someone please take a look at the log and let me know what you think the problem is?

Hi @hoppy1977

check motors and ESCs
there is a motor/esc failure in your log

1 Like

Thanks Hosein,
That is really helpful.

So exactly how should I interpret that?
Can we tell from that graph if it is RCOU.C9 or RCOU.C10 that is at fault, or is there not enough information?

I notice when looking at the RCOU values over the whole flight, RCOU.C10 seems to be working a lot harder than the other motors:

I wouldn’t have expected this in a simple autopilot flight (i.e. no acrobatics).

Does this indicate that perhaps that motor is the culprit?

Grateful for any further assistance.

When an esc/motors fails you can see a line in rcout values thats faild motor is maxed and opposite motor goes to minimum because flight controller try to keep balance

Its hard to say that is was a motor problem pattern
It was cloud becase of flying against wind, wrong motor kv or physically imbalance

yes , the reason of crash was that motor failure

1 Like

I was flying in stabilize mode and after 6 min flight at around 0.5m altitude. suddenly the drone moving toward backward direction very rapidly and smashed into my bag. By god grace all was fine only the props were damaged. But i am unable to understand what has happened. I am attaching my log, Please have a look @hosein_gh


Hi @AmitSingh
Please create a topic and describe your problem there and i will look into that
This post is for @hoppy1977 and i dont want to hijack this topic

1 Like

A more thorough description would be a Loss of Thrust. It could certainly be a motor failure but a failed prop or ESC will present the same result.

1 Like

i have posted a new topic for my problem @hosein_gh @dkemxr
Please have a look at Instant pitch backward in stabilizing mode leading to crash - ArduCopter - ArduPilot Discourse