I lost my I1 because GPS signal dropped out

[Toan Doan]

Last weekend, while flying on top of a waterfall, my I1 changed the flight mode from P-GPS to ATTI mode by itself in a crucial moment, it drifted so quick within a second and I could not steer it away from a tree branch near by and felt down to the falls. Sadly, it did not survive the crash

As I didn't change the flight mode, and I trusted the aircraft system before I took off with enough signal and number of satellites. All green lights and good to go. But then this happened still when it was only 50m away from me.

Checked the flightrecord on the ipad, it showed that, at the moment I drifted there was 9 satellites, but the aircraft still changed the flight mode by itself from P-GPS to ATTI. Sent the log to Dji, they said even though there were still enough satallites, but once GPS signal dropped (I dont understand: GPS vs satellites, are they diff??), the aircraft changed to ATTI mode automatically and drifted as a result

They rejected my claim, not sure what to go from here as I only followed what the device told me to do, and trusted it, yet this happened. It's easy to blame myself but what should I do differently? What would you do? One thing I do learn is "never trust P-GPS as it can still change"

 

[The Editor]

Last weekend, while flying on top of a waterfall, my I1 changed the flight mode from P-GPS to ATTI mode by itself in a crucial moment, it drifted so quick within a second and I could not steer it away from a tree branch near by and felt down to the falls. Sadly, it did not survive the crash

As I didn't change the flight mode, and I trusted the aircraft system before I took off with enough signal and number of satellites. All green lights and good to go. But then this happened still when it was only 50m away from me.

Checked the flightrecord on the ipad, it showed that, at the moment I drifted there was 9 satellites, but the aircraft still changed the flight mode by itself from P-GPS to ATTI. Sent the log to Dji, they said even though there were still enough satallites, but once GPS signal dropped (I dont understand: GPS vs satellites, are they diff??), the aircraft changed to ATTI mode automatically and drifted as a result

They rejected my claim, not sure what to go from here as I only followed what the device told me to do, and trusted it, yet this happened. It's easy to blame myself but what should I do differently? What would you do? One thing I do learn is "never trust P-GPS as it can still change"

Correct - never put 100% trust in any automated system and be ready and totally confident to fly in P-Atti at any moment.

You should be happy to fly in P-Atti in any condition you would fly with GPS assistance. That means if you would fly at 400ft in 25 mph winds with GPS, you must be confident to do the same in P-Atti.

Sorry you lost your aircraft but lesson learned.....practice, practice practice Atti flying in all scenarios.

 

[roninsteel]

Agreed, I have lost GPS several times at crucial moments, but keeping an eye on the craft, instrumentation, potential hazards is key. As the above.poster says you should be fully conversant in flying in atti, personally I try to get two full hours a month doing that which doesn't sound like a lot but really. Makes the difference, it's a real shame, as. It is a very expensive lesson to learn

 

[RvdH]

Same happened to me. See my recent post.

Learned that more than some other pilots experienced the same, DJI replaces the birds in most cases.
What firmware? What version GO app?

 

[Kilrah]

Checked the flightrecord on the ipad, it showed that, at the moment I drifted there was 9 satellites, but the aircraft still changed the flight mode by itself from P-GPS to ATTI.

GPS function also depends on the validity of the compass data. If the compass is disturbed (e.g. a metallic mass in the nearby rocks) the aircraft can't continue to make use of the GPS data even if it's valid, and has to drop to ATTI.

 

[IrishSights]

9 satellites is pretty low. If it was me I would not fly in P-GPS with 9 when flying in an an environment like you described. Starting off in atti would have been safer...that's why being confident in atti is so important. I reckon the view of the sky was obscured blocking the number of satellites. The ones you did have some might have been low strength and momentarily dipped below the safe level and it switched to atti. Not much comfort I know in hindsight.

PFAW Holder
BNUC-S Qualified

 

[RaptorMan]

Waterfalls are often within gorges that can really limit the view of the sky near the horizon. Any place that has rock walls that limit the view of the sky can limit the GPS signal as well.


Brian

 

[Toan Doan]

Thanks guys for your input. I do fly in ATTI mode from time to time, generally in a more open space to get a smoother shot. In saying that, even though I've already had over 30hrs flying time with that I1, I'm still learning and trying to put on ATTI mode as much as possible whenever I can. But in that specific location where I didn't have much room to play with. I took the risk and moved the aircraft to that position while putting on the break and it did hold on the break for about 5-10 secs while I was trying adjust the camera angle then that happened. Oh well, I learned my lesson. Time for the new I1 v.2.
Cheers

 

[Toan Doan]

9 satellites is pretty low. If it was me I would not fly in P-GPS with 9 when flying in an an environment like you described. Starting off in atti would have been safer...that's why being confident in atti is so important. I reckon the view of the sky was obscured blocking the number of satellites. The ones you did have some might have been low strength and momentarily dipped below the safe level and it switched to atti. Not much comfort I know in hindsight.

PFAW Holder
BNUC-S Qualified

At some points, it catched up to 20 satellites when flying above the trees, but it dropped down to 10-12 as I get closer to the tree line then to 9 at that moment. I really have no idea that it dropped so quick. But yes, I will be learn from this. Thanks!

 

[Toan Doan]

Same happened to me. See my recent post.

Learned that more than some other pilots experienced the same, DJI replaces the birds in most cases.
What firmware? What version GO app?

They didn't in my case, thats why I was curious. They said it was the pilot fault for not controlling the aircraft! I cant do much about it.

 

[Toan Doan]

Agreed, I have lost GPS several times at crucial moments, but keeping an eye on the craft, instrumentation, potential hazards is key. As the above.poster says you should be fully conversant in flying in atti, personally I try to get two full hours a month doing that which doesn't sound like a lot but really. Makes the difference, it's a real shame, as. It is a very expensive lesson to learn

Thanks, it's kind of the first time I1 did that too me so I was shocked! But I learned my lesson.

 

[Toan Doan]

Correct - never put 100% trust in any automated system and be ready and totally confident to fly in P-Atti at any moment.

You should be happy to fly in P-Atti in any condition you would fly with GPS assistance. That means if you would fly at 400ft in 25 mph winds with GPS, you must be confident to do the same in P-Atti.

Sorry you lost your aircraft but lesson learned.....practice, practice practice Atti flying in all scenarios.

If I had more room or took the bird a bit higher above the tree line in that location, yes ATTI mode all the way, but not in a space that I had at that time. It was on the break and it did hold on to the break for 5-10secs then it changed and drifted so quick in a sec while I was adjusting the camera angle. But thanks for your advice. I've been flying with my I1 for sometimes now and I'm quite confident with it. But with this accident, it changed my view completely. I'll be more careful next time! Lesson learned!

Cheers

 

[Terry G]

GPS function also depends on the validity of the compass data. If the compass is disturbed (e.g. a metallic mass in the nearby rocks) the aircraft can't continue to make use of the GPS data even if it's valid, and has to drop to ATTI.

Good information to know. Now a question with this in mind. Should you loose P mode and go into ATTI and your able to regain control, will the craft return to P mode if it travels far enough away from what ever caused it to drop into ATTI mode? I have experienced the "strong interference" message during calibration but never when airborne. Thanks.

 

[Kilrah]

Yes.

Also note that when signal starts getting bad it may take a little while until the aircraft does the switch, during which it may behave erratically or seem not to respond to controls. If at this point you switch to A mode manually you'll regain control quicker.

 

[Toan Doan]

Yes.

Also note that when signal starts getting bad it may take a little while until the aircraft does the switch, during which it may behave erratically or seem not to respond to controls. If at this point you switch to A mode manually you'll regain control quicker.

On this note, if we're flying in A mode and the signal is dropped out, the screen's gone blank. In theory, after 10sec, the RTH will kick off. But within that 10sec, while you lost control and it is still dripping as a result of A mode...that could be a potential hazard too. Right?

 

[Kilrah]

Which "signal"? We're talking of GPS/compass signal here. There's also the video signal, and the control signal... all of them are independent and will need different actions / will result in different behaviors depending on which of them are lost.

If you lose video you may still have control so RTH would not necessarily kick off. If you also lost control signal then yes it would, it's maybe only 1 second after the loss of control signal though, not 10 seconds. If you're in A and lose video (and are lost, but you should not since you should be having the machine in sight ) then definitely switch to P ASAP to avoid it drifting uncontrolled. If at that moment you've got bad luck and also have no GPS/compass signal then you're basically screwed (which is why you should be in range and capable of taking back control visually in A mode).

 

[Toan Doan]

Which "signal"? We're talking of GPS/compass signal here. There's also the video signal, and the control signal... all of them are independent and will need different actions / will result in different behaviors depending on which of them are lost.

If you lose video you may still have control so RTH would not necessarily kick off. If you also lost control signal then yes it would, it's maybe only 1 second after the loss of control signal though, not 10 seconds. If you're in A and lose video (and are lost, but you should not since you should be having the machine in sight ) then definitely switch to P ASAP to avoid it drifting uncontrolled. If at that moment you've got bad luck and also have no GPS/compass signal then you're basically screwed (which is why you should be in range and capable of taking back control visually in A mode).

Yes I was talking about the video signal while the aircraft is still in A mode. But thanks for your detailed explanation. I guess, when the video signal is lost, a simple and safe way is to flick the flight mode back to P-GPS and/or kick off the RTH straight away, then take a deep breath and pray for the screen to come back. If nothing showing up then...oops!

 

[Beverly Hills Aerials]

flying near a water fall is pretty high risk if you ask me. i wouldn't attempt flights like that unless you have mastered control of your drone. meaning that you can fly in attitude mode comfortably, perform figure 8's forwards, backwards, and move the drone in any direction including reverse orientation slowly and controlled. props for going for it and flying close to a waterfall though.... post the low res footage from the dji go app at least so we can pay tribute to its last flight.

 

[lake_flyer]

flying near a water fall is pretty high risk if you ask me. i wouldn't attempt flights like that unless you have mastered control of your drone. meaning that you can fly in attitude mode comfortably, perform figure 8's forwards, backwards, and move the drone in any direction including reverse orientation slowly and controlled. props for going for it and flying close to a waterfall though.... post the low res footage from the dji go app at least so we can pay tribute to its last flight.

And all that also with a lot of wind, preferably first with a full manual copter. Atti is still very assisted.

 

[The Editor]

In addition to all of the above many people fail to take into account (or even know of the existence and affect) of Anabatic and Katabatic winds in mountainous or steeply sloped regions or up or down river.
Understanding your intended flying environment and doing a risk analysis and site survey BEFORE you fly are of paramount importance - even if you are a hobby flyer you should take all factors into account.