Flyaways

[Tom Croley]

Obviously, having a flyaway drone is a painful experience. Most often it is pilot error of some kind. Sometimes it is an actual problem with the drone and DJI seems pretty good at looking at the cases and replacing defective drones. I was amazed to read stories where they replaced a drone.

After my flyaway experience, I started reading other stories and found a lot of them. Mine ended happily with the drone landing safely about 100 feet away. The cause.... I was flying with a heavy fog cover that started about 125 feet up. When my grandson pressed the RTH button, the Spark rose to 100 feet and then just kept going into the fog until it reached max altitude, then it would not come down until the battery was low. It was confused by the fog.

If you are worried about your Sparkie flying off, just go to Google and put in the name of any other drone and add the word "flyaway." You will find that they all fly away sometimes. The Parrot Bebop II is particularly bad. So the problem is not unique to the Spark by any means.

Consumer technology is not perfect. It is a blend of price vs performance. You cannot expect the GPS receiver in your $600 drone to be as good as the GPS receiver in a F-18 Hornet. GPS Sats only transmit at 25.6 watts of power and they are about 11,000 miles away. The quality of the reception varies a lot by your location, buildings, clouds, trees etc. If you are using a good hand held GPS, you can watch the bar indicators change as you move around. Then there is compass interference, wifi interference, etc. etc.

I think the best thing we can do is make sure you do a good pre-flight check. Pay attention to GPS lock and wifi interference, calibrate the compass when needed, then keep a sharp eye on your battery level during flight. In addition, practice flying the drone in sport mode to increase your skill at manually controlling the drone rather than just depending on the technology.

 

[Mike_in_Letcombe]

On most ‘flyaway’ posts, I read a line where I think ‘..that’s what caused this’. Flying near metal structures / no gps / inclement weather...most of us can fill in the blanks. Occasionally, bad luck has a leading role but the vast majority are errors - how many times have we seen ‘my first / second flight went wrong..’. You have given great advice and acknowledged the issue you experienced, so well done. I just wish some people would take the time to learn these basic facts or use common sense. If one of these falls on a kids head and injures them, our hobby is toast. I fear it’s a matter of when, not if..

 

[bath1968]

Obviously, having a flyaway drone is a painful experience. Most often it is pilot error of some kind. Sometimes it is an actual problem with the drone and DJI seems pretty good at looking at the cases and replacing defective drones. I was amazed to read stories where they replaced a drone.

After my flyaway experience, I started reading other stories and found a lot of them. Mine ended happily with the drone landing safely about 100 feet away. The cause.... I was flying with a heavy fog cover that started about 125 feet up. When my grandson pressed the RTH button, the Spark rose to 100 feet and then just kept going into the fog until it reached max altitude, then it would not come down until the battery was low. It was confused by the fog.

If you are worried about your Sparkie flying off, just go to Google and put in the name of any other drone and add the word "flyaway." You will find that they all fly away sometimes. The Parrot Bebop II is particularly bad. So the problem is not unique to the Spark by any means.

Consumer technology is not perfect. It is a blend of price vs performance. You cannot expect the GPS receiver in your $600 drone to be as good as the GPS receiver in a F-18 Hornet. GPS Sats only transmit at 25.6 watts of power and they are about 11,000 miles away. The quality of the reception varies a lot by your location, buildings, clouds, trees etc. If you are using a good hand held GPS, you can watch the bar indicators change as you move around. Then there is compass interference, wifi interference, etc. etc.

I think the best thing we can do is make sure you do a good pre-flight check. Pay attention to GPS lock and wifi interference, calibrate the compass when needed, then keep a sharp eye on your battery level during flight. In addition, practice flying the drone in sport mode to increase your skill at manually controlling the drone rather than just depending on the technology.

A great comment... [emoji3] [emoji106]

 

[nutsnbolts]

So my biggest concern with my two drones that I just got (spark and platinum mavic pro) is flyaways.

Honestly I'm still trying to figure out what really is the cause for flyaways other than the fact that it's due to Magnetic interference, loss of GPS signal, Wi-Fi interferences Etc.

I know many people have stated that it's usually pilot error and not having a thorough PreFlight checklist. I'm curious though that even with a thorough PreFlight checklist and ensuring that there is no magnetic interference and having a strong GPS signal and no wifi interference, before taking off. Does it fly away after the fact because one of the symptoms may have come out of nowhere while flying or is it because the pilot never checked all of the above before taking off?

I'm still unclear and unsure to have a comfortable feeling flying this thing anywhere.

 

[Spark 317]

I'm still unclear and unsure to have a comfortable feeling flying this thing anywhere.

You gotta crawl before you can walk.
Take baby steps and your confidence will follow.

 

[Tom Croley]

I agree....baby steps is the key. Don't over blindly trust the technology

Technology is not perfect at this price...or any price for that matter. So be cautious but don't be paranoid. With consumer GPS, there are always unknowns. I cannot count the times my hand held, rather expensive, Garmin GPS has lost contact simply because I walked into a wooded area, or too close to tall buildings...etc, etc. So don't assume that since you have a good lock, that's going to be true for the whole flight.

Then there are anomalies in the atmosphere.... like "stove pipe thermals." I was flying my RC 2 meter sailplane one day in the field next to my house. I was drifting along about 400 feet up just going straight and having a good time. Suddenly, the glider flew into a strong stove pipe thermal. Instantly, the nose kicked up, and the wings ripped clean off, breaking in half, and then the fuselage plunged down like a missile. Stuff happens! So, fly cautiously, keep your aircraft in sight, and practice enough so you can fly it home manually using the sticks. There's no substitute to being in control.

You could add, "dumb mistakes" to your list too. Don't start a flight with a battery that is already low...trying to squeeze in one more. That's one.... I wonder how many more can be added to this list?

 

[suprPHREAK]

So my biggest concern with my two drones that I just got (spark and platinum mavic pro) is flyaways.

Honestly I'm still trying to figure out what really is the cause for flyaways other than the fact that it's due to Magnetic interference, loss of GPS signal, Wi-Fi interferences Etc.

I know many people have stated that it's usually pilot error and not having a thorough PreFlight checklist. I'm curious though that even with a thorough PreFlight checklist and ensuring that there is no magnetic interference and having a strong GPS signal and no wifi interference, before taking off. Does it fly away after the fact because one of the symptoms may have come out of nowhere while flying or is it because the pilot never checked all of the above before taking off?

I'm still unclear and unsure to have a comfortable feeling flying this thing anywhere.

Had a long answer but my iPad ate it (seriously hate iOS). here is the short version:

100% of fly aways are rooted in compass errors. Without compass, GPS is useless so the drone ignores it, and goes into atti mode. Atti mode is supposed to fly flat and level with no stick input, but if the IMU was not properly calibrated, it will fly away.

To prevent them:

1- do an IMU calibration on a FLAT AND LEVEL SURFACE. This instrument is not sensitive to metal, so whatever you use. The IMU calibration, among other things, creates the reference point for where level is. If this is incirrect, the drone will enter whatever position it thinks is level...and if that position is tilted, then the drone will move in that direction, and continue to accelerate.

2- do a compass calibration as far away from metal as possible. Middle of a soccer pitch, baseball outfield, middle of a corn field. If you calibrate with interference, then when you fly up in the air away from the metal, the robot will interpret the lack of interference as an error. Also, when calibrating, be a couple metres from your mobile device. Put it on the ground, take a few steps away. I read somewhere this matters.

3- dont take off from metal or concrete (which usually contains metal). In theory, when you take off and leave that interference, things should be OK, but it could introduce unpredictable flight behaviour.

When people say flying within 100m of a pop can will cause compass errors, that is BS. If you follow the above, you should be OK once airborn, near almost any structure.

Also, the Mavic is far more fault tolerant than the Spark, as it uses dual IMU and dual compass. The result is it can filter errors better, adding some insurance before things go wrong.

Let me know if you want the very detailed answer.

 

[nutsnbolts]

Had a long answer but my iPad ate it (seriously hate iOS). here is the short version:

100% of fly aways are rooted in compass errors. Without compass, GPS is useless so the drone ignores it, and goes into atti mode. Atti mode is supposed to fly flat and level with no stick input, but if the IMU was not properly calibrated, it will fly away.

To prevent them:

1- do an IMU calibration on a FLAT AND LEVEL SURFACE. This instrument is not sensitive to metal, so whatever you use. The IMU calibration, among other things, creates the reference point for where level is. If this is incirrect, the drone will enter whatever position it thinks is level...and if that position is tilted, then the drone will move in that direction, and continue to accelerate.

2- do a compass calibration as far away from metal as possible. Middle of a soccer pitch, baseball outfield, middle of a corn field. If you calibrate with interference, then when you fly up in the air away from the metal, the robot will interpret the lack of interference as an error. Also, when calibrating, be a couple metres from your mobile device. Put it on the ground, take a few steps away. I read somewhere this matters.

3- dont take off from metal or concrete (which usually contains metal). In theory, when you take off and leave that interference, things should be OK, but it could introduce unpredictable flight behaviour.

When people say flying within 100m of a pop can will cause compass errors, that is BS. If you follow the above, you should be OK once airborn, near almost any structure.

Also, the Mavic is far more fault tolerant than the Spark, as it uses dual IMU and dual compass. The result is it can filter errors better, adding some insurance before things go wrong.

Let me know if you want the very detailed answer.

Yes please I'd like a bit more detail. Thanks for taking the time to explain. It makes sense so far.

My first questions are in calibrating the IMU. I'm assuming if it is showing green in the app that means it's calibrated correctly? I mean calibration doesn't seem complicated when you perform it so how much can you screw it up? Unless whoever is calibrating ignores the green red and yellow warning? Also if the IMU is required calibrating the app usually tells you in the beginning.

The 2nd questions is the same thing when calibrating the compass. How do you know at the end of the day that both are correctly calibrated for sure?

 

[Povl H. Pedersen]

I trust GPS and RTH 100% in my drones and planes. So do many others. I am not afraid to fly missions way beyond video/tx signal range. It will come back, unless it as a mechanical error. Friend did a 120km autonomous there and return flight with a plane this summer (60+60km). Over open ocean when out of range.
The old M6N compass takes forever to lock to sats, but are fine once locked in. And there are more sats than 6 above ground.
Modern GPS like M8N / or BN-880 locks on in seconds, and gets way more sats. Really good. GPS in spark is super as well.

My planes with iNav does not use the compass at all. Knowing a plane always moves forward, it will do fine with GPS only (until the wind is strong enough to blow it backwards). My planes usually needs at least 10-12 m/s airspeed to stay aloft.

iNav on quads need the compass, like the DJI drones. And if the compass works, and the drone has a valid home position, it will return if wind permits. If not, take over manual control, go as low as possible (5-10-15ft) and use the controller to go home. Wind at <15ft is likely way less than above. Some fly aways (especially with phone as controller) has been due to going up in too strong winds, getting clrea of the house, and wind just taking it for a ride.

Be aware the Spark allows for dynamic home position in tracking mode. So home position can be near its current position depending on how you fumble with the controls on the phone/tablet.

 

[suprPHREAK]

Yes please I'd like a bit more detail. Thanks for taking the time to explain. It makes sense so far.

My first questions are in calibrating the IMU. I'm assuming if it is showing green in the app that means it's calibrated correctly? I mean calibration doesn't seem complicated when you perform it so how much can you screw it up? Unless whoever is calibrating ignores the green red and yellow warning? Also if the IMU is required calibrating the app usually tells you in the beginning.

The 2nd questions is the same thing when calibrating the compass. How do you know at the end of the day that both are correctly calibrated for sure?

First Answer: All sensor calibration has a range which is considered "in the green". If you calibrate the IMU with a 2-degree tilt, it may still be "green", but obviously that tilt will be an issue, as stated. I don't know what that range is, but this is why I say it is important to calibrate, as instructed on a perfectly flat and level surface, so that you are as close to a perfect calibration as possible. The steps also involve having the drone at 90 degrees to the ground, so in a best case scenario, also use a proper vertical surface for those steps, although I find this is not as critical as the flat and level surface step.

Second answer is the same, there is a range of "good". When I last calibrated my compass, I got values as low as 30, but I think it goes yellow at 300. That's a big "OK" range. So, if you calibrate at 280, the drone says this is OK, but then you only need 20 points interference to get an error. I am not sure what these numbers represent, specifically, but this is why a proper, interference-free calibration is required.

Point is: "green" is a range, and if you are near the outside of that range, you can get interference easier.

For the longer answer, I think I'll make a separate post, since this is a common question anyway.

 

[nutsnbolts]

First Answer: All sensor calibration has a range which is considered "in the green". If you calibrate the IMU with a 2-degree tilt, it may still be "green", but obviously that tilt will be an issue, as stated. I don't know what that range is, but this is why I say it is important to calibrate, as instructed on a perfectly flat and level surface, so that you are as close to a perfect calibration as possible. The steps also involve having the drone at 90 degrees to the ground, so in a best case scenario, also use a proper vertical surface for those steps, although I find this is not as critical as the flat and level surface step.

Second answer is the same, there is a range of "good". When I last calibrated my compass, I got values as low as 30, but I think it goes yellow at 300. That's a big "OK" range. So, if you calibrate at 280, the drone says this is OK, but then you only need 20 points interference to get an error. I am not sure what these numbers represent, specifically, but this is why a proper, interference-free calibration is required.

Point is: "green" is a range, and if you are near the outside of that range, you can get interference easier.

For the longer answer, I think I'll make a separate post, since this is a common question anyway.

Thanks let me know when you have posted it. I would really want to understand the true in and outs with it. Color is color but the numerical value i think is more important. I guess if the color is fluctuating green to yellow. I'm Not going to even take a chance.

As far as IMU. Is there a full proof way to tell precisely that it's perfectly calibrated?

 

[nutsnbolts]

On a side note on another post that msinger pointed out about compass calibration. He stated that even if it's green a good way to tell as well is to confirm and check the map and make sure the arrow points north or it's not spinning around.

I think that is a good advise in general.

 

[Mrmund]

On most ‘flyaway’ posts, I read a line where I think ‘..that’s what caused this’. Flying near metal structures / no gps / inclement weather...most of us can fill in the blanks. Occasionally, bad luck has a leading role but the vast majority are errors - how many times have we seen ‘my first / second flight went wrong..’. You have given great advice and acknowledged the issue you experienced, so well done. I just wish some people would take the time to learn these basic facts or use common sense. If one of these falls on a kids head and injures them, our hobby is toast. I fear it’s a matter of when, not if..

Here Here! Thanks for posting this

 

[Povl H. Pedersen]

IMU = Inertial Measurement Unit. Shows up/down and rate of turn. In principle a gyroscope.
Calibration on other quads is just handheld. Giving it an idea about direction/orientation. You can then finetune it by changing angle if you want it to always fly forward in neutral. But it does not need super precision.
For flying home, 10 degrees off by the IMU should not mean much, same with compass. Fly aways is a larger problem. 20 degrees off by the compass would likely cause it to fly smaller and smaller spirals around the taget. Not fly away.

 

[GOttira]

As a new spark owner I gotta say i'm a bit nervous about taking it up. I only have about 3 packs through it as I'm still learning. Used it with my Note 8 and about 10 feet up I got a disconnect error several times. I since bought an Ipad mini and only have 1 pack through it but didn't get the disconnect error so I think I'm OK. I have calibrated the IMU and Compass once just to know how to do it.

 

[Robert G]

I believe one way to test if the imu is level and correct is to force the spark in to atti mode. Indoor test may do, or some put foil over the gps to test outdoors.

 

[myko]

As a new spark owner I gotta say i'm a bit nervous about taking it up. I only have about 3 packs through it as I'm still learning. Used it with my Note 8 and about 10 feet up I got a disconnect error several times. I since bought an Ipad mini and only have 1 pack through it but didn't get the disconnect error so I think I'm OK. I have calibrated the IMU and Compass once just to know how to do it.

Same. Ive also been reluctant to go far due to all these flyaway stories. Does it generally happen mostly when people hit the RTH button or can it happen during other instances as well?

 

[Hotwire]

Flying with just a phone or tablet is asking for trouble. Phones use WiFi to control the aircraft and once out of range everything is done by the autonomous flight controller. If the AFC has the wrong compass or GPS config it's goodby Spark.

Always do preflight checks of compass, GPS, props and connection. If anything looks odd, sort the issue before continuing, always! Don't takeoff from bear ground because debris can get in the motors or cooling system, use a mat or your carry case or best, hand launch. The easiest way to hand launch is to setup the Fn button on the controller for TAKEOFF Function. Once in the air, check it's behaving properly and not making strange noises.

When RTH switch to the map page. Watch the direction and altitude the aircraft is at. Sometimes it's hard to know if Spark has responded to RTH, the app with say if it is but the button on the controller may signal even if it isn't coming back. When it's coming back the altitude is important because you may not see or hear it returning. Don't try and direct the craft during RTH , if you can see the aircraft and want to take control, hit cancel and land manually.

Using 'hand gestures only', don't! Because it could do something weird and you are helpless to stop it.

Antennas work by being at right angles to the receiver, so don't point the antennas at the aircraft. If the aircraft is away from you point the antennas vertically, if the aircraft is straight above you set the antennas level. Antenna signal is like a big doughnut with the antenna itself in the hole. Loosing signal means the drone is on its own and maybe bye bye.

 

[myko]

Flying with just a phone or tablet is asking for trouble. Phones use WiFi to control the aircraft and once out of range everything is done by the autonomous flight controller. If the AFC has the wrong compass or GPS config it's goodby Spark.

Always do preflight checks of compass, GPS, props and connection. If anything looks odd, sort the issue before continuing, always! Don't takeoff from bear ground because debris can get in the motors or cooling system, use a mat or your carry case or best, hand launch. The easiest way to hand launch is to setup the Fn button on the controller for TAKEOFF Function. Once in the air, check it's behaving properly and not making strange noises.

When RTH switch to the map page. Watch the direction and altitude the aircraft is at. Sometimes it's hard to know if Spark has responded to RTH, the app with say if it is but the button on the controller may signal even if it isn't coming back. When it's coming back the altitude is important because you may not see or hear it returning. Don't try and direct the craft during RTH , if you can see the aircraft and want to take control, hit cancel and land manually.

Using 'hand gestures only', don't! Because it could do something weird and you are helpless to stop it.

Antennas work by being at right angles to the receiver, so don't point the antennas at the aircraft. If the aircraft is away from you point the antennas vertically, if the aircraft is straight above you set the antennas level. Antenna signal is like a big doughnut with the antenna itself in the hole. Loosing signal means the drone is on its own and maybe bye bye.

From what ive read, the rc also uses wifi connection to the aircraft as well, so i assume the same types of disconnect may happen as well. I suppose the rc just has a stronger wifi connection which minimizes the disconnect chances?

 

[Hotwire]

From what ive read, the rc also uses wifi connection to the aircraft as well, so i assume the same types of disconnect may happen as well. I suppose the rc just has a stronger wifi connection which minimizes the disconnect chances?

That would be some WiFi, especially from the aircraft, as the range is claimed to be 2km. Normal RC work in the same frequency band with ranges up to 5km. There is no reason Spark wouldn't have 2 transponders or more.

Most people who buy DJI aerial camera are not RC hobbyists. They are likely to opt for the phone as a cheap Tx and that would be a scenario for a fly-away. Spark is a great little aerial platform but normal RC principles and procedures apply.