It is a SMAJ51A diode, for circuit protection. Please notice that there are risk as your are repairing a damaged board. Nobody tells if there could be any other unnoticeable damage.
Yes there are chance of an un noticeable damage, Also I check the board and it was working fine without this diode also with all respect. But I will still take care about this.
The electronics boards must be always underplated with some insulation layer that in case of crash can prevent to burn down of the whole copter. I use for example 2 types depends on the size of copter.
CNC machined laminated board o glasstextit board.
3D printed PLA plate or board underneath the electronics.
Maybe it few grams extraweight but definitely save your electronics. Also the design is very important to have maximum strenght at the center plane of the copter to get electronics protected
@Legacy600 Thank you very much for your suggestions, I will follow the same next time.
Also you can help me out to know the exact cause of the crash that occurred, it would be great for me in future and also what other precautions needs to be taken.
Also if you can let me know what should we do to protect the copter from the compass interferences and EKF. Also attaching the logs below for reference.
From the binary log in the drive, none of them recorded a crash.
To avoid compass interferences, put your compasses as far as possible from high power electronics such as cables and motors. Typically we suggest >10cm.
Conduct CompassMot to let your autopilot about magnetic field pattern generated by your motors.