Normal Flight -> Atti mode -> Compass Error -> Atti mode -> Normal Flight - What happened?

Spark
1

Posted this over on SparkPilots and posting here too (Hope that’s allowed - delete if not)

Was flying my Spark on Friday checking out ice conditions off of a local beach area that I have flown from numerous times and towards the end of the flight GO4 announced it was in Atti Mode. Glancing at the phone screen it then went to Compass Error, then back to Atti mode and eventually back to normal flight. The AC was in VLOS the whole time so when it went to Atti mode, I turned around and headed back. The compass error gave me a scare as I was worried about loosing control of the AC, however this does not appear to have happened as I was able to get back and land. I was flying over water that had frozen then thawed so there were lots of ice chunks floating around - would have been impossible to recover the AC if it had went down. The launch area was a grassy area covered in wet snow just up from the beach. It is an area I have launched in numerous times and as far as I know there was no metal nearby.

I have owned my Spark for just over 2 years and this is the first time I have ever had a compass error. The log file is linked below. Problems start at 5m 47.8s with Yaw Errors. I would really like to know what happened so that this does not happen again, so any help in figuring this out is greatly appreciated.

Flight Log

AirData Link

Additional info: I hand launch my Spark most times and did so this time as well.

Thanks,

Chris

2

Hi
Could this be temperature related?

3

Thanks for you reply. Don’t think so as I have flown in much colder conditions without any problems. Did a flight today and it was -15C and everything was fine.

Chris

4

Hi Chris, what about wind gusts? I had the same thing happen to me and it was collectively determined here that a swift and sudden gust may have knocked the IMU and GPS out of sync briefly, I did have to fly back in ATTI, like you it was still in LOS… fortunately. It was a seemingly nice day, a bit breezy, summertime. I did both calibrations after that and all was well again, in fact, many flights later, no issues.

5

Hi Northwood,
I don’t think it was wind gusts as It wasn’t windy that day. Also, I had it happen on a couple of more flights, again on days it was not windy. I have since recalibrated the compass and have not had any issues since.

What puzzles me is that if the compass needed calibration, then why didn’t the app tell me to do it.

Chris