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aha1973
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Few weeks ago I suffered my first spark accident. I decided to log a ticket to support and the response so far from support has been Pilot fault, but I cannot agree.

1. The home point was recorded during flight which does no make sense at all.
2. The RTH was triggered although I was about to land, which also makes no sense.

Has anyone experienced a similar issue?

Kind Regards
Alex
2018-10-16
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JJBspark
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Hi Alex,

To make it better to understand do upload your flightlog, if you like ofcourse.

use this link  http://www.phantomhelp.com/LogViewer/Upload/  

1. if you fly away with low sat count its possible that the HP is recorderd during flight.
2. during a (manual) landing the RTH can be triggered.  

Flightlog will tell more.

cheers
JJB



2018-10-16
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aha1973
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Hi JJB,

I will try to upload the logs later, however, what sense is there, in recording the HP during flight? This makes no sense in my view. The HP could mean land anywhere. Do you agree?
2018-10-16
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msinger
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That's why you should never take off until the home point has been set. Or manually reset it mid-flight if it's set to an undesirable location.
2018-10-16
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aha1973
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I have uploaded the flight log.

Whilst the lessons learned is not to take off until the home point has not been set, I cannot agree that the HP is recorded during flight, this should never happen. Furthermore, I'm most of the time concentrating on the aircraft not on the screeen. I'm not quite sure is there is an audible alert that could be set to advise.  Furthermor, the software on the sparkshould be clever enough to tell that my altitude was almost 0 and thus about to land. The RTH should not be tirggered under certain altitude.
2018-10-16
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aha1973
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http://www.phantomhelp.com/LogViewer/NGJ4J9RQIRDUIZCG3O08/
2018-10-16
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msinger
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After reviewing your flight log, it looks like pilot error to me too.

This is how all DJI drones work. You should definitely carefully review the Spark manual so you understand how the drone is supposed to function. If needed, you can download the manual here:

https://www.dji.com/spark/info#downloads
2018-10-16
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JJBspark
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aha1973 Posted at 2018-10-16 03:21
I have uploaded the flight log.

Whilst the lessons learned is not to take off until the home point has not been set, I cannot agree that the HP is recorded during flight, this should never happen. Furthermore, I'm most of the time concentrating on the aircraft not on the screeen. I'm not quite sure is there is an audible alert that could be set to advise.  Furthermor, the software on the sparkshould be clever enough to tell that my altitude was almost 0 and thus about to land. The RTH should not be tirggered under certain altitude.

Hi Alex,

You started to fly in OPTI mode, beacuse too low sat count for good GPS and no GPS reception at the beginning of your flight (zero on scale 0 -5)
So your Spark could not set a HP that time.

Flying away in OPTI is a choice of the OP, when during flight GPS becomes "availiable" a HP is set! In your case 35 meters away from your takeoff point.
If you want to fly i suggest you wait in the hover closeby to see if a HP is set, than start to fly further. But carefull ; OPTI mode can go into ATTI....

In OPTI mode you cannot go high, that`s why the warning "Max Altitude Approached. Wait for the GPS satellite signal recovery before ascend." see the manual for that.

This RTH became active due to low batt, DJI calculates the neccessary power to gohome. What the OP is flying that stage, doesn`t matter. So your Spark was acting according how it should be doing. (see the crossing lines)

SO bottom line, both remarks you made are normal uhh? wtf-questions, but if you read the manual and get more understanding how it works than you will never be in this situation again. (i think/hope)

Happy safe landings in the future!
cheers
JJB






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2018-10-16
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aha1973
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Dear All,

Thanks for the explanations provided so far, however I still cannot agree with some of the findings. The Spark user manual states the following:

"If a strong GPS signal was acquired before takeoff, the Home Point is the location from which the aircraft launched. The GPS signal strength is indicated by the GPS icon (  ). The aircraft status indicator will blink rapidly when the home point is recorded. "

Based on the above the HP should only be recorded before take off, never during flight, which makes absolutley sense as recording the HP during flight could lead to a non desired landing site.

The user manual also states the following in regards RTH Low-Battery:

"The  thresholds  for  these  warnings  are  automatically  determined  based  on  the  aircraft’s  current  altitude  and  distance from the Home Point. Low-Battery RTH will only appear one time during flight."

From the screenshots provided, can you let me know what was the altitude of the aircraft before the RTH was triggered? The automatic thresholds of the aircrfat should have noticed the aircraft was clearly about to land, thus no RTH should have been triggered. What are these automatic triggers, specially altitude? The Spark does not have sensors above the aircraft, but it does have on the bottom, didn't the sensor record proximity to the ground before the RTH was triggered?

The documentation also states that the RTH is only triggered once per flight, however after the RTH was triggered and the spark hit some tree branches, I was able to avoid the first collision and I tried to land the spark on the roof but this is were the Spark decided to rise once again and eventually hit the tree branches again. This time I was not able to avoid the collision.


Finally, I certainly don't know, but thus the RTH trigger any audible alarm on the application?

Kind Regards,
2018-10-16
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aha1973
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One additional question on the log viewer what are the color codes on the flight sticks?
2018-10-16
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S-e-ven
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aha1973 Posted at 2018-10-16 05:23
Dear All,

Thanks for the explanations provided so far, however I still cannot agree with some of the findings. The Spark user manual states the following:

"Based on the above the HP should only be recorded before take off, never during flight, which makes absolutley sense as recording the HP during flight could lead to a non desired landing site"

Nope, you are wrong, here

Not only, but ONLY IF a strong GPS signal is available at/before take off.
Meaning ~12 sats available.

Aside that you could have set the homepoint to your phones location, after it set the homepoint to the bird alone, and that you could have cancelt the  RTH, I think you should start to youtube a bit, about RTH and other secrets of DJI drones.
I hope the repair cost is not to high.
But Following this topic, I cant see anyone else at fault as the pilot, here.

2018-10-16
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aha1973
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I certainly read the spanish document and there is no doubt in my view. The Home Point should have only be recorded prior to take off if GPS signal strong. Provided the first condition was not met, I cannot see where in the documentation it is stated that the HP will be recorded during flight.

2018-10-16
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msinger
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"From the screenshots provided, can you let me know what was the altitude of the aircraft before the RTH was triggered?"

At 12m 10.9s into your flight, DJI GO showed you this message to let you know the battery was low and the Spark was going to automatically return home in 10 seconds:



The Spark was 2 feet from the ground at that point (according to the downward sensors). Since you did not tap "Cancel" to cancel the automatic RTH procedure, the Spark started returning home at 12m 20.5s (10 seconds later). Had you tapped "Cancel", you likely would not have ended up in this situation.


"The automatic thresholds of the aircrfat should have noticed the aircraft was clearly about to land, thus no RTH should have been triggered"

The automatic thresholds of aircraft determined your Spark needed to return home since it was 94 feet away from the home point. It doesn't matter how high the Spark is in the air when RTH is initiated. Only the distance from the home point will prevent it from flying back to the home point (as described in the Spark manual).


"didn't the sensor record proximity to the ground before the RTH was triggered?"

Yes, but the proximity to the ground is not used when determining whether or not the Spark needs to return home.


"but thus the RTH trigger any audible alarm on the application"

It usually does if the volume is turned up on your mobile device.


"The documentation also states that the RTH is only triggered once per flight"

Your Spark only attempted to return home once. Since you did not cancel RTH after it had been initiated, it kept attempting to return home as you were fighting it with the remote controller sticks.


"on the log viewer what are the color codes on the flight sticks?"

On my log viewer? Yellow means the stick is in the center. Orange means it's somewhere in the middle. Red means it's extended as far as it'll go.
2018-10-16
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aha1973
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Based on the last response from msinger, it’s really hard for me to understand what is the logic behind the fact that distance can be more important than height. The logs reveal the spark was only two feet away from the ground, and the sticks should also indicate I was trying to land, and even the proximity sensors did notice.  I have also not received any response either about what sense does it make to record a home point during flight..

There are some lessons learned on the accident, but I certainly cannot accept it was entirely my fault.  
2018-10-16
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JJBspark
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aha1973 Posted at 2018-10-16 07:31
Based on the last response from msinger, it’s really hard for me to understand what is the logic behind the fact that distance can be more important than height. The logs reveal the spark was only two feet away from the ground, and the sticks should also indicate I was trying to land, and even the proximity sensors did notice.  I have also not received any response either about what sense does it make to record a home point during flight..

There are some lessons learned on the accident, but I certainly cannot accept it was entirely my fault.

Hi Alex,

about your "I have also not received any response either about what sense does it make to record a home point during flight..."

Software is not like AI, its stupid but made with logic. Logic is to start fly when the drone has enough sats to fly stablized and enough sats+reception to know its position for marking a HomePoint.
If you start to fly away in other conditions than above the software marks a homepoint when enough etc...

Is this clever? Mayby not mayby yes, but its how this software deals with this situation.

If not happy make a complaint to DJI.

cheers
JJB
2018-10-16
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JJBspark
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aha1973 Posted at 2018-10-16 05:23
Dear All,

Thanks for the explanations provided so far, however I still cannot agree with some of the findings. The Spark user manual states the following:

RTH was triggered at 28.8 meters from HP (wich was 35 meters away from takeoff point), drone had a VPS height of 1.2 meter.

You wrote "The logs reveal the spark was only two feet away from the ground, and the sticks should also indicate I was trying to land"
At that point only about 31% down stick so for the sofware that is normal flying and not yet into a forcelanding. Forcelanding starts after few ticks after 100% down at low height normally from a hover situation; flight mode is than changed from P-GPS to ForceLanding.

So its not a pilot error, its just to less knowledge of the manual and how the drone acts in situations.
PS a RTH low battery can be cancelled, quick way is to press the pause button! Flying in GoHome mode can be controlled with sticks but then you have do stick down to prevent it from going up. After cancel Drone will react normal at stick inputs.

cheers
JJB



2018-10-16
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aha1973
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JJBspark Posted at 2018-10-16 10:29
Hi Alex,

about your "I have also not received any response either about what sense does it make to record a home point during flight..."

I agree it's definitively not the best to take off without all the correct data, but there can be many reasons for the system to take off without the right amount data, and my thinking would never record a home point once the aircraft has taken off. The Spark does not have the capability to decide, that is why there is a Pilot.

What if the aircraft took off from a hangar (no GPS) and the move outside. Could we agree that the software can be improved?
2018-10-16
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aha1973
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JJBspark Posted at 2018-10-16 11:02
RTH was triggered at 28.8 meters from HP (wich was 35 meters away from takeoff point), drone had a VPS height of 1.2 meter.

You wrote "The logs reveal the spark was only two feet away from the ground, and the sticks should also indicate I was trying to land"

The response from msinger was that the spark was 2 feet from the ground, as per the logs, I have not yet the capacity to tell. However you are stating the VPS height was 1.2 meters. On the DJI app I can see that at 12:06 the height was -0.6 which makes sense as the aircraft took off from the top of a table and I was to land on the floor which matches the fact that the height was negative.

Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height.
2018-10-16
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aha1973
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aha1973 Posted at 2018-10-16 12:40
The response from msinger was that the spark was 2 feet from the ground, as per the logs, I have not yet the capacity to tell. However you are stating the VPS height was 1.2 meters. On the DJI app I can see that at 12:06 the height was -0.6 which makes sense as the aircraft took off from the top of a table and I was to land on the floor which matches the fact that the height was negative.

Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height.

Before the RTH was triggered the IMU altitude was -1.3 ft.
2018-10-16
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Gunship9
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RTH is surprisingly confusing to cancel.  After taking off with less than a half charged battery, I cancelled RTH twice by making a mistake the first time.  RTH cancel button will ask you if you want to cancel the return to home when you select it.  It gives you the option of okay, or cancel.  Hitting cancel will cancel the cancel of RTH.  You have to hit cancel then okay.  It was confusing in the sunlit screen.  I hear pause button works but haven't used it yet.

I've never used RTH because I don't trust it to fly better than me.  
2018-10-16
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S-e-ven
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aha1973 Posted at 2018-10-16 12:40
The response from msinger was that the spark was 2 feet from the ground, as per the logs, I have not yet the capacity to tell. However you are stating the VPS height was 1.2 meters. On the DJI app I can see that at 12:06 the height was -0.6 which makes sense as the aircraft took off from the top of a table and I was to land on the floor which matches the fact that the height was negative.

Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height.

-Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height -

Because there is a homepoint, the bird has to get back to.
GPS is a failsafe function, in case you loose RC contact or forget about the battery, p.ex.
That is at first a distance, the bird is calculating how much juice is needed, to get back to HP before 10% battery.
And as I mentioned earlier:
You could have changed the HP to the devices location,
or waited with flying away, till HP is recorded.
Or you could have cancelt the RTH at any time.

Not knowing functions is pilot error, imho, not software fault.

Book it under experience and learn out of it.
Or you could get you a toy drone.
They are a lot cheaper and dont have GPS at all.
Solved!



2018-10-16
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aha1973
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S-e-ven Posted at 2018-10-16 17:47
-Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height -

Because there is a homepoint, the bird has to get back to.

A home point which was set during flight. . I cannot find anywhere in the documents something that states that home point will be recorded during flight.

We might never get to any agreement, but I certainly prefer to land far from my position but safely. The software could really tell: :the height, the flight sticks, the bottom sensors can definitively tell if there is a clear intention on the pilot to land and therefore overrule the decision to trigger the RTH.
2018-10-16
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JJBspark
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aha1973 Posted at 2018-10-16 12:30
I agree it's definitively not the best to take off without all the correct data, but there can be many reasons for the system to take off without the right amount data, and my thinking would never record a home point once the aircraft has taken off. The Spark does not have the capability to decide, that is why there is a Pilot.

What if the aircraft took off from a hangar (no GPS) and the move outside. Could we agree that the software can be improved?

Its easy to agree on your last point ; software improvent is an walking proces....

Do not agree on the rest, just read and understand the manual.

cheers
JJB
2018-10-16
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JJBspark
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aha1973 Posted at 2018-10-16 12:40
The response from msinger was that the spark was 2 feet from the ground, as per the logs, I have not yet the capacity to tell. However you are stating the VPS height was 1.2 meters. On the DJI app I can see that at 12:06 the height was -0.6 which makes sense as the aircraft took off from the top of a table and I was to land on the floor which matches the fact that the height was negative.

Refering back to user manual where the thresholds are based on height and distance, I can't think why distance would be more important that height.

Yes VPS height is not the barometric height. Last value can be negative, VPS is never negative!
If you do not know what VPS height is; see lots of YT vids, read manual etc.

We all are entitled to have our own opinion on all happenings in live ; you are hard to convince. No problem but than my response end here.
But enjoy flying drones, many happy landings and if you find a drone wich 'listen' excactly to your thought, let me know   

cheers
JJB


2018-10-16
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aha1973
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JJBspark Posted at 2018-10-16 22:48
Yes VPS height is not the barometric height. Last value can be negative, VPS is never negative!
If you do not know what VPS height is; see lots of YT vids, read manual etc.

Jjb,

You keep taking for granted that I did not look at the documentation at all. Can you be so kind to point me in the official DJI documents where it is stated that home point can be recorded in flight?  On the DJI app user manual I can only see a simple description on what the H means. In Spanish it simply says height from ground.
2018-10-16
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aha1973 Posted at 2018-10-16 23:09
Jjb,

You keep taking for granted that I did not look at the documentation at all. Can you be so kind to point me in the official DJI documents where it is stated that home point can be recorded in flight?  On the DJI app user manual I can only see a simple description on what the H means. In Spanish it simply says height from ground.

Alex,

Your question was answered in my post # 15.

HomePoint can only be set if there is GPS sats and reception. That`t it.
Fly away from take point is possible like you did in OPTI mode with a height restriction.
Flying low further is possible, once there is SAT ect this software marks a HP during flight.
This situation is not described in the manual as it is a situation wich should not occur, beacuse DJI drone flyers wait for a GPS lock before flying.
H on the screen in the app means HomePoint.

VPS height will change during flight in distance to homepoint and back again if VPS height is in sensor range.

cheers
JJB
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wimherman
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aha1973 Posted at 2018-10-16 07:31
Based on the last response from msinger, it’s really hard for me to understand what is the logic behind the fact that distance can be more important than height. The logs reveal the spark was only two feet away from the ground, and the sticks should also indicate I was trying to land, and even the proximity sensors did notice.  I have also not received any response either about what sense does it make to record a home point during flight..

There are some lessons learned on the accident, but I certainly cannot accept it was entirely my fault.

The distance is important, because distance is effected by weather condition e.x. wind.. ! going down doesn't cost the same amount of energy as flying against the wind direction.. Thank you Newton ..
2018-10-17
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aha1973
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Tiny question, I always use the automatic take off, should this be recorded in the flight log? Shoudn't it provide some safe guarding rails to help rookies like me?
2018-10-17
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msinger
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aha1973 Posted at 2018-10-17 00:04
Tiny question, I always use the automatic take off, should this be recorded in the flight log? Shoudn't it provide some safe guarding rails to help rookies like me?

That was recorded in your flight log. At the beginning, you'll see the flight mode was set to "Auto Takeoff".
2018-10-17
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aha1973 Posted at 2018-10-16 22:28
A home point which was set during flight. . I cannot find anywhere in the documents something that states that home point will be recorded during flight.

We might never get to any agreement, but I certainly prefer to land far from my position but safely. The software could really tell: :the height, the flight sticks, the bottom sensors can definitively tell if there is a clear intention on the pilot to land and therefore overrule the decision to trigger the RTH.

The app should tell you that
"Home point recorded, please check it on the map"
As soon as the HP IS recorded.
So pop up the volume and CHECK it next time
Is it in the air 500m away,  or on the table in front of you, as soon the bird reads enough GPS sats to get a GPS fix "for sure", it will record that: The first GPS location after switched on becomes HP
2018-10-17
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Flighty
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Pilot Error,,, Sufficient GPS locked, and displayed, plus HP recorded is a fundamental process to do before any flying off into the distance. JJBspark has explained it perfectly!
2018-10-17
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aha1973
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Can anyone explain what it is considered on a automatic take-off?
2018-10-17
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aha1973 Posted at 2018-10-17 03:25
Can anyone explain what it is considered on a automatic take-off?

You sliding "are you sure you wanna start?", on the screen from left to right, the bird takes off alone and "parks" in about 1m height.
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aha1973
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S-e-ven Posted at 2018-10-17 04:52
You sliding "are you sure you wanna start?", on the screen from left to right, the bird takes off alone and "parks" in about 1m height.

I will open another thread as I need to understand what are the advantages of using the automatic take off
2018-10-17
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Imho that is a start you need to perfom without a RC
I have not tried it yet, but I think the CSC is not working with virtual sticks on the display.
Anyone has tried that?
2018-10-17
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aha1973 Posted at 2018-10-16 23:09
Jjb,

You keep taking for granted that I did not look at the documentation at all. Can you be so kind to point me in the official DJI documents where it is stated that home point can be recorded in flight?  On the DJI app user manual I can only see a simple description on what the H means. In Spanish it simply says height from ground.

Alex, as you have correctly quoted, the manual says "If a strong GPS signal was acquired before takeoff..."

It doesn't say "Only when a strong GPS....", it says "If...".  When there is an "IF" condition, there is always an "ELSE" condition even if it isn't explicitly outlined.  In this case, they haven't explicitly outlined what happens if that condition isn't met.  However, that doesn't then mean that nothing else happens.

I think it would be great if you would follow up with DJI to get them to explicitly define what happens in the manual so as to make it clearer for everybody.  I also agree that DJI should always be making their algorithms better and smarter.  I would suggest you formally pass along those suggestions for them to consider via opening a support ticket with them directly.

However, having said that, I think it is also important, that we as the humans running these machines also look to improve ourselves as well and take responsibility for ourselves and our property.  I made a video about a year ago on this topic.  Its not the most entertaining video (maybe best watched at 1.5x speed), but I think its important for us all to take into mind.



Cheers!

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aha1973 Posted at 2018-10-17 04:53
I will open another thread as I need to understand what are the advantages of using the automatic take off

I made a video a while back showing different methods of launching the Spark.  Not sure if it answers what you are looking for, but thought I would share in case it does...

2018-10-17
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KlooGee Posted at 2018-10-17 09:18
Alex, as you have correctly quoted, the manual says "If a strong GPS signal was acquired before takeoff..."

It doesn't say "Only when a strong GPS....", it says "If...".  When there is an "IF" condition, there is always an "ELSE" condition even if it isn't explicitly outlined.  In this case, they haven't explicitly outlined what happens if that condition isn't met.  However, that doesn't then mean that nothing else happens.

(maybe best watched at 1.5x speed)

In 1.5 it is entertaining, I think!
Thanks
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S-e-ven Posted at 2018-10-17 10:18
(maybe best watched at 1.5x speed)

In 1.5 it is entertaining, I think!

Lol!  If you think 1.5x is entertaining, you should go for the full 2x!  
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S-e-ven
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I did that with the
"4way" video
2018-10-17
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