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Quarry flight with sudden ATTI mode

dougiefresh27

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Here is the link to the flight

Here is the link to the flight record DJI Flight Log Viewer - PhantomHelp.com

Finally found a spot to fly from on a calm day during the Covid-19 crisis But only a short time into the flight the DJI Spark went into ATTI mode and began a sudden RTH.

Thankfully it landed safely. I think the power lines caused the issue due to magnetic interference confusion with the GPS location.

I'm just glad it didn't take off in a different direction.

It just came back towards me and I took controls and landed
 

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Northwood Mediaworks

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Well, my take on this.. first a question. What was the wind profile like at your highest point in the flight? Wondering if you might have had a small gust as well as the interference.... and, when you go into Atti mode, RTH does not work. Therefore if it was coming back, there must have been enough wind to push it your way (luckily. Glad you were able to take control and pilot back. Interesting that GPS recovered on its own near the end of the flight.
 

pstik

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You know I have had issues to where I am flying with no issue. LOS and then I hear atti mode. I cannot tell which way it's facing. Then it takes off. I scramble to make sure I get it flying back to me. Then it will recover. But I bring it home anyhow. I have seen this more then I like. Seems it happens more often then before. Some times because of the sky it is hard to see because it blends in. If you are watching the screen then hear atti mode I have to scan hard and fast to find it. I have good satellite coverage when I take off.
 
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dougiefresh27

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You know I have had issues to where I am flying with no issue. LOS and then I hear atti mode. I cannot tell which way it's facing. Then it takes off. I scramble to make sure I get it flying back to me. Then it will recover. But I bring it home anyhow. I have seen this more then I like. Seems it happens more often then before. Some times because of the sky it is hard to see because it blends in. If you are watching the screen then hear atti mode I have to scan hard and fast to find it. I have good satellite coverage when I take off.
This was the first time I heard ATTI mode. Why is this happening?
 

RotorWash

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This was the first time I heard ATTI mode. Why is this happening?
The compass onboard the craft is used in conjunction with GPS for navigation. If the compass data is off kilter for whatever reason the craft will drop GPS and go into ATTI mode (or OPTI if low enough) as it can no longer trust its own data and doesn't want to fly in a direction that the pilot's stick commands didn't intend and then become hard to control.

The transmission lines are a common suspect but I'm also suspect of your takeoff/landing area. When you turned the bird on and then launched was it near any vehicles (within 10') during that time? This can cause your compass to be irregular and it may not show up as a problem right away. Parking lots like the one you were in also have underground power lines, maybe pipes and sometimes rebar or wire mesh.

When you were pitching forward heading out I noticed you holding the right stick some degrees to the right, did you feel you had to compensate to keep the craft going straight at the time or was that just the path you wanted to take? You were fortunate with your flight back as it was in ATTI mode (RTH requires GPS) with little stick input and only started using GPS during your manual decent to land. Nice job there btw.
 
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dougiefresh27

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The compass onboard the craft is used in conjunction with GPS for navigation. If the compass data is off kilter for whatever reason the craft will drop GPS and go into ATTI mode (or OPTI if low enough) as it can no longer trust its own data and doesn't want to fly in a direction that the pilot's stick commands didn't intend and then become hard to control.

The transmission lines are a common suspect but I'm also suspect of your takeoff/landing area. When you turned the bird on and then launched was it near any vehicles (within 10') during that time? This can cause your compass to be irregular and it may not show up as a problem right away. Parking lots like the one you were in also have underground power lines, maybe pipes and sometimes rebar or wire mesh.

When you were pitching forward heading out I noticed you holding the right stick some degrees to the right, did you feel you had to compensate to keep the craft going straight at the time or was that just the path you wanted to take? You were fortunate with your flight back as it was in ATTI mode (RTH requires GPS) with little stick input and only started using GPS during your manual decent to land. Nice job there btw.
Very insightful.
Yes, I was in a Walmart parking lot 4 feet from my bumper
I also was compensating with the stick to one side to make it go in the intended direction

I'm making all kinds of hasty mistakes.
Today, the RTH point updated 130' away and 50' up
I need to be more patient and let the bird get all of its settings to a happy status
Maybe I need a lead lined launch pad Red Spark Small.jpg
 
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RotorWash

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Nice color scheme you got going on there! There's a learning curve for sure but that's part of the fun so keep those props spinning! One good tip to help prevent taking off from a magnetically distorted location is to check the AC's heading indicator (red arrow) in the GO4 app map display or attitude indicator and see if it's consistent with the AC's actual heading.

Here's an informative video on compass errors if you're interested.

(video ends at 12:10)
 
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Congrats on getting your craft back! One question that keeps me wondering though. That's the issue with power line interference. I live about 400 feet from a substation with voltages from 12,470 up to 115,000. I routinely fly around, over and close to, many times within 5 to feet of, those lines and transformers. I have never had an issue where my spark showed any influence from the electrical lines. Maybe I've been lucky, but I believe that the spark is more immune to 60 cycle electrical interference than a lot of people like to believe.
 

pstik

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I had atti mode kick in more often lately. So I did the IMU and compass cal. I have been flying sparkybutt with more confidence. Have not had any atti mode issues. I think I will cal the IMU and compass at least once a year. I know they say do it only when spark says you need one. I have not needed to do 1 since I got the spark according to the spark. But I believe after doing the cal it is stabilized.
 

Northwood Mediaworks

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Always do these cals away from metal, and any other signal producing or metalic items, like your house, your watch, concrete, your smartphone. If you can get someone to hold your phone 20 feet away when doing the compas cal, and you've even removed your metal betl buckle, having them call out when to change directions, etc... that is the ideal way to do it. Zero chance of interference and miscalculation. That is what my wife is for! LOL
 

Spark 317

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It's just a wild thought I had, and I doubt that it could have an impact on the flight, but what are they mining in the quarry?

It looks like a regular gravel pit, but is it possible that there may be some iron ore that could effect the Spark?
The ground doesn't look rusty so that's probably not the case.

Like I said, just a doubtful thought, but a thought nevertheless.🤔
 

dougiefresh27

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Well, my take on this.. first a question. What was the wind profile like at your highest point in the flight? Wondering if you might have had a small gust as well as the interference.... and, when you go into Atti mode, RTH does not work. Therefore if it was coming back, there must have been enough wind to push it your way (luckily. Glad you were able to take control and pilot back. Interesting that GPS recovered on its own near the end of the flight.
Wind was below 10 mph. All I saw was ATTI mode then RTH mode. Then I took control. Either way it scared me. Red Spark Small.jpg
 

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