I was flying a weeks old Mavic air and for the first time was trying ActiveTrack modes. My air was following me quite well, when it was at 8 meters height and 316 meters away from me suddenly without any other warning my a.c. got disconnected and it fall down.. resulting broken arm, camera got hurt and some scratches.

  

Now when i try to fly, it display "sensor error (c3)" what does it actually mean. Can i calibrate its sensor using "DJI Assistant 2" make it working?

  
  

Note: Prior to that incident several times i faced problem with poor image transmission. (Go4 app & firmware was well up-to-date)

  

It means that it is time to send it for repair. Not only you broke that arm, but something is damaged inside your Mavic.

The sensors are basically misaligned and no doubt caused by the crash - you can do a calibration of the VPS via Assistant 2 but as PS013 pointed out you are better off raising a ticket with DJI support and shipping the drone back if one of the arms is broken. Who knows what additional internal damage has been done to the drone too.

Nath, I am sorry for the crash. Could you please provide me with the crash data from the drone for a further check? Please export the data via the DJI Assistant 2, upload to Dropbox and paste the link here. Thank you.
As for now, please also send the drone in, we will help to make data analysis for this crash, if it's a warranty case, we will get your drone repaired/replaced with no charge according to our After-sales Policy. Please contact our support to start a case: http://www.dji.com/support

DJI Thor Posted at 2018-3-8 18:51
Nath, I am sorry for the crash. Could you please provide me with the crash data from the drone for a further check? Please export the data via the DJI Assistant 2, upload to Dropbox and paste the link here. Thank you.
As for now, please also send the drone in, we will help to make data analysis for this crash, if it's a warranty case, we will get your drone repaired/replaced with no charge according to our After-sales Policy. Please contact our support to start a case: http://www.dji.com/support

details in this location:
https://drive.google.com/drive/u ... 4hynh4qWXS0eNnhEuwq