pro 2 just auto landed on water ,couldnt over ride .gone included csv log please help

[slabcharger]

log included can someone please explain why

DJI Flight Log Viewer - PhantomHelp.com

 

[Meta4]

csv log included can someone please explain why

Nothing was attached.
But rather than a CSV, it would be more useful to attach your .txt file or a link to the Phantomhelp or Airdata report for the flight.

 

[slabcharger]

Nothing was attached.
But rather than a CSV, it would be more useful to attach your .txt file or a link to the Phantomhelp or Airdata report for the flight.

DJI Flight Log Viewer - PhantomHelp.com

 

[Meta4]

DJI Flight Log Viewer - PhantomHelp.com

You launched from high above sea level, flew out over the water and descended towards the water.

For a lot of the time after 1:58.5, your VPS sensors were indicating something just 0.3 - 0.6 metres below the drone.
There are indications that this was not a genuine height reading.
Did you have something fitted under the drone that might have blocked the VPS sensors?

At 5:01.8 you held the left stick fully down for a second.
The combination of the false low VPS indicated height and holding the left stick fully down overcame landing protection and initiated the autolanding.

You should have been able to cancel the autolanding by holding the left stick up, but you only did that for less than one second at 5:04.8 and otherwise left the drone to continue landing.

Another problem that didn't cause the loss of the drone, but could have in other circumstances was that you started with a battery that was already partially discharged.
Doing that, the % indication gives you a false idea of how much is in the battery.
At 3 seconds, on takeoff, the cell voltage was already down to critical low voltage level (3.2 volts).
Within a few seconds you switched to Sport Mode and pushed the right stick full forward which dragged the cell voltage below critical low voltage level.

 

[slabcharger]

You launched from high above sea level, flew out over the water and descended towards the water.

For a lot of the time after 1:58.5, your VPS sensors were indicating something just 0.3 - 0.6 metres below the drone.
There are indications that this was not a genuine height reading.
Did you have something fitted under the drone that might have blocked the VPS sensors?

At 5:01.8 you held the left stick fully down for a second.
The combination of the false low VPS indicated height and holding the left stick fully down overcame landing protection and initiated the autolanding.

You should have been able to cancel the autolanding by holding the left stick up, but you only did that for less than one second at 5:04.8 and otherwise left the drone to continue landing.

Another problem that didn't cause the loss of the drone, but could have in other circumstances was that you started with a battery that was already partially discharged.
Doing that, the % indication gives you a false idea of how much is in the battery.
At 3 seconds, on takeoff, the cell voltage was already down to critical low voltage level (3.2 volts).
Within a few seconds you switched to Sport Mode and pushed the right stick full forward which dragged the cell voltage below critical low voltage level.

The drone has always had a shifty sensor on the bottom
So I leave it off, I actually turned it on the day before maybe that's the problem.i forgot to turn off.I usually have all sensors off. I get close to the water but never too close . The fact is it engaged the landing which only is done when you slide the landing sliders .then pressing x cancels it. I would of only been 5m above the water so rapidly pressing x then holding up and nothing was working. It was a freezing morning maybe 8 degrees . But I always fly with partially discharged battieres . This photo was taken . Second later it engaged landing I was -25m it then got to -33 m when it hit the water .

 

[Phantomrain.org]

With this kind of flying you should consider getting the Rain and Rescue Package from Phantomrain.org so you can fly in the Rain and Float on the Water for your Drone.

Phantomrain.org
Gear to fly in the Rain. Land on the Water.

 

[Zbip57]

I would love to see the full video of this flight, as that would tell us more. But it really looks like the issue is that you brought the drone too low to the wavetops.

It looks like you already had a fright earlier, starting at 3m 33.9s (See your PhantomHelp log.) You took off from the parking lot at the top of the cliff, then lowered the drone -82.3ft down to near water level and 2,165ft away, to watch the surfers on the large breaking waves. At that distance, there's no way you can accurately judge the drone's height above the water's surface by line of sight. You're relying entirely on the camera view for that (not that I personally see anything wrong with that).

But something weird happens in the PhantomHelp log at that point. Usually the time increment in the log steps up by a consistent 0.1 secs. (i.e. 3m33.6s, 33.7s, 33.8s, 33.9s, 3m34s, etc) But aftert 3m34s the log jumps a full second to 3m35s, then skips a whole 2.2s to 3m37.2s. That's weird because the CSV still shows consistent 0.1sec increments.

During that weird interval the CSV file shows you held the throttle stick full down for almost 2secs from 3m35.8s until released to centre at 3m37.6s. At 3m37.7s the VPS height shows as only 0.6ft!! Is that the actual height above the top of the wave, or is that just the spray coming off the wave as shown in your photo?

Either way, the drone sinks as low as -87.2ft, another five feet lower than previously, until at 3m45.6s you suddenly give it full up throttle and the drone rockets straight up, gaining 145ft, up to +29ft displayed before heading back to shore, as shown by the vertical yellow line ending at 40% battery shown below. Were you afraid you had dunked it there?



After you reassured yourself that everything was okay, you lowered the drone and headed right back out to the wave.

So why did it auto-land?

Again, the PhantomHelp log and the CSV file show slightly different things.

At 4m59.6s, the PhantomHelp log and the CSV file both show throttle at midpoint and height at -80ft. But the PhantomHelp log shows VPS height as N/A, whereas the CSV height lists it at 1.6ft.

The CSV file records at the usual 0.1s intervals, but the PhantomHelp log jumps from 5m0.3s, 5m.1.5s, to 5m2.7s right at the critical moment when auto-landing is commanded. But, both do show the throttle being held down.

The CSV file does show the throttle held fully down from 5m1.8s to 5m2.4s, during which time the VPS height briefly goes as low as 0.9ft. I don't know how it works with your Mavic2Pro, but if my Mavic Mini is within 2ft above any obstacle detected by the VPS height sensors (even mist off waves or waterfalls) and the throttle is held full down, that commands an auto-landing.

On my Mini, auto-landing can be aborted several different ways. A quick press on the Home button, or on the X in the app screen, will instantly cancel any of its autonomous modes, like RTH or any other automated Quickshot flight modes. Simply giving full up throttle will also stop any normal auto-landing, or even delay a low-battery forced landing.

The PhantomHelp and CSV log files both continue for another 13secs after you confirmed the intent to auto-land. The logs show the throttle stayed at mid-position for those 13secs, before the log ultimately stops.

 

[old man mavic]

@slabcharger , to sum it all up from the wonderfully detailed analysis from the posts above ,
and to explain why ,then the only conclusion for the drones watery demise was pilot error
these things happen

 

[TonyPHX]

@slabcharger , to sum it all up from the wonderfully detailed analysis from the posts above ,
and to explain why ,then the only conclusion for the drones watery demise was pilot error
these things happen

"watery demise" - OMM you never disappoint and you have a way with words. : )

 

[slabcharger]

no possible way. as i said 100s of hours shooting alot closer and alot crazier waves with massive swells when its not even a wave breaking. people surfing confirmed. it was safely high. aalogt higher than i get because surf wasnt even amazing . after it went into auto landing i tapped the x 50 times , wiped screen to makle sure wasnt that kept pressing. i wouldnt care if was pilot error as i said , thats why im trying to work it out. iv pushed these thibgs to the limit in 50 knot winds 3 kms out to sea countless times. i can assure you wasnt my error . hell i even beat dji in a insurance case after they gave me a 3rd drone under dji care when only 2 are permitted. i even had the sensors on whicch i never do.without them on yes hold down and it will land . but on they want you to swipe to confirm. ps i always fulll throtttle up after a 5 shot burst because im close to the wave and the burst lags the screen so like to make sure im away as far from the salt spray .

 

[slabcharger]

im happy to push the limits and lose a drone for the shot, thats why user error wouldnt phase me . this does because i cant have this happen again . as i said its my 6th mavic 2 . one thing i will add is it has always had a dodgy botttom sensor why i usually have ooff. just the day before i was filming kids motorcycle through trees and had several beers under my belt

 

[Phantomrain.org]

If the Landing Sensor does get wet and does not clear the drop off the sensor ,it can force land.
This is why we protect the Landing Sensor in the Rain whey flying with the Wet Suit. So you assumption of the Landing Sensor getting confused is a possibility.

Phantomrain.org
Gear to fly in the Rain < Land on the Water.

 

[Zbip57]

no possible way. [...] i can assure you wasnt my error .

I wasn't there, so I'm not judging. Just saying, in a panic situation it's often difficult to recall exactly what happened and when which buttons were pushed. The flight log says what it does.

i even had the sensors on which i never do.

Obstacle avoidance sensors, or VPS sensors? Can the VPS sensors even be switched off? Either way, it doesn't matter as you say sensors were enabled.

without them on yes hold down and it will land . but on they want you to swipe to confirm.

Like I said, I don't know how it works with a Mavic2Pro...

I don't know how it works with your Mavic2Pro, but if my Mavic Mini is within 2ft above any obstacle detected by the VPS height sensors (even mist off waves or waterfalls) and the throttle is held full down, that commands an auto-landing.

My Mini uses the DJI Fly app, whereas your Mavic2Pro which uses DJI GO 4. So there may well be differences in functionality.

With mine, I can either press the button on the app screen from any height to initiate auto-landing, which then requires a push and hold to confirm the intent to auto-land. Or I can simply lower the throttle to make the drone descend. But when it reaches a height of 0.5m (~2ft) detected by the VPS height sensor, it stops and won't go any lower than that. At that point, holding the throttle full down confirms the intent to land and auto-landing kicks in to softly set the drone down.

*If* your Mavic2Pro is similarly programmed, and the VPS height sensor detects it is within 2ft of "ground" and you're holding the throttle full down, that is the signal to engage auto-landing. The flight log clearly shows this to be the case. It also shows the throttle stick was released at mid-point and never moved, while you were fumbling with pressing buttons on the screen.

Was the VPS height sensor measuring that height from the actual top of a wave, or from the spray coming off the top of the wave? Your photo seems to show the drone at very nearly the height of the spray.

 

[Yorkshire_Pud]

Can the VPS sensors even be switched off?

I have the vague recollection that with the Mavic 2 VPS can be switched off......but it is a vague recollection.

 

[Yorkshire_Pud]

after it went into auto landing i tapped the x 50 times

If, as has been suggested both here and in the DJI forum, the auto landing was triggered by the combination of VPS reading and down stick, then has anyone else verified that the action i.e. the resulting landing-protection auto-landing, can be cancelled by a screen button action?
Normally I doubt anyone has the time to do that.

The above said, there is plenty of evidence that the correct response would have been full throttle ............ and that you did not do.

To be honest if this was your sixth wrecked or lost Mavic 2 I would suggest you should re-evaluate your flying, for the safety of others if nothing else.

 

[Zbip57]

If, as has been suggested both here and in the DJI forum, the auto landing was triggered by the combination of VPS reading and down stick, then has anyone else verified that the action, the resulting landing, can be cancelled by a screen button action?
Normally I doubt anyone has the time to do that.

Exactly. You can push the button on screen and swipe to confirm you want an auto-landing from any desired height. If you start from a high enough altitude you'll have plenty of time to reconsider whether you want to press the X button to cancel the landing.

But, if the auto-landing is commenced from only a 0.5m (2ft) height because you held the throttle stick full down to override the landing protection feature, that doesn't leave you a lot of time to change your mind before the drone has landed.

The above said, there is plenty of evidence that the correct response would have been full throttle ....

For example, starting at 1:13 in the video below, I recently demonstrated the landing protection feature with my Mini. Holding the throttle partially down will slowly lower the drone only until the VPS height sensor detects it is 0.5m (2ft) from the surface. Even if I continue to hold the throttle partially depressed, landing protection prevents the drone from descending any further. But, if I then push the throttle all the way down, that triggers auto-landing and the drone will automatically land itself. (The gimbal on the Mini automatically rotates the camera up to horizontal to avoid sticking the lens into the ground.)

I didn't actually want it to land yet and, because I was paying close attention and expecting it to do that, I immediately raised the throttle to cancel the auto-landing. It took less than a second to stop the landing that way. From only 0.5m (2ft) up, there surely wouldn't be enough time to fumble with pushing buttons or swiping on the app screen.

 

[Zbip57]

no possible way. [...] i can assure you wasnt my error [...] it was safely high. a lot higher than i get because surf wasnt even amazing.

It's too bad we don't have video to see what actually happened. But your still photo is very helpful. It shows the drone is well high enough safely above the wave and surfer. But I suspect the spray showing above the wave is what caused all the problems.

The CSV flight log file shows your throttle inputs as you raise and lower the drone high enough above the wave crests and then down into the next trough. That's indicated in the fluctuating barometric altimeter readings -80ft down from your takeoff location. Meanwhile, the VPS height sensor readings alternate between reading "N/A", when the drone is high enough above the water's surface to be out of range of the infrared sensors, to sometimes alarmingly close when the sensors are detecting "something" very close beneath the drone.

From your photo, I strongly suspect the VPS infrared height sensors are detecting the spray above the waves. Even though the drone is well clear of the wave itself, the sensors still "see" the spray. At the moment the wave passes by underneath the drone, the height sensor "sees" the spray only 0.9ft below. You have the throttle pulled all the way down, intending to have the drone dive down into the following wave trough. Unfortunately that combination, VPS height less than 2ft and full down throttle, is the signal to engage auto-landing.

I've had the same thing happen to me when flying over the edge of a waterfall. The drone was still way up high in the air, when the app suddenly announced "Landing"! That happened because the VPS height sensor detected the spray off the waterfall as I was holding the throttle stick down. Luckily I had plenty enough time to react to that.

In your case, from the moment auto-landing was initiated, the flight log shows the drone took another 13 seconds to descend a further 24ft before the log cuts out at splashdown. Throttle up should have stopped that.

 

[Yorkshire_Pud]

If you start from a high enough altitude you'll have plenty of time to reconsider whether you want to press the X button to cancel the landing.

I don't and didn't doubt that that from "on high" an auto landing can be cancelled via the screen button but I am curious about whether or not the landing protection landing phase can be cancelled via a screen button press. The two? 'sorts' of auto landing need not use the same rules.

I guess I'll need to charge a battery and make some experiments lol possibly with a 'hand held' flight.

 

[Meta4]

Can the VPS sensors even be switched off?

With drones that use DJI Go 4, the VPS can be enabled/disabled

Was the VPS height sensor measuring that height from the actual top of a wave, or from the spray coming off the top of the wave?

It was giving a constant false reading of 1-2 ft, despite the drone ascending/descending 20 ft or more.
This is not reading spray or anything real.

 

[Zbip57]

It was giving a constant false reading of 1-2 ft, despite the drone ascending/descending 20 ft or more.
This is not reading spray or anything real.

I don't know. It still kinda makes sense.

Here's the initial part of the flight. The Blue line is throttle up/down. Red line is the barometric height zero at the parking lot takeoff location. Green line is the VPS height sensor.

Sitting on the ground before takeoff, OSD height zero ft, the VPS is showing 0.3ft (~3½ inches). Does the Mavic2 have legs that long?

Full up throttle for takeoff, it climbs to 8ft above the parking lot and flies forward at that level height. The VPS height fluctuates as the drone passes over (parked cars? or bushes?) over a deeper gully then very low over (another bush?), until reaching the cliff edge.

Then there is a brief blip of down throttle, the drone descends from its 8ft height to zero height (same level as the parking lot) as it flies out past the cliff edge and then the bottom drops away. VPS height goes to "N/A" and the Green line disappears as the ground is now out of range of the VPS height sensor.

More down throttle blips as the drone is lowered down to sea level dropping down to hold around -50ft for a while, then lowering more to -77ft until, at around 118secs (1m58s), the Green line reappears as the VPS height sensor detects "something".


The next graph continues from the point where the Green line restarts... Gotta go for dinner, back later...