Bad luck, bad drone, or bad pilot

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Hi community,


I have completed numerous flights with my own, personal drone without incident (phantom 3 advanced) but have at three incidences in not so many flights with my work's drone (phantom 4 professional).

This has left me questioning my sanity - do I have bad luck, am I a bad pilot, or was the drone a lemon.

My incidents are described below

The first incident was a mission on the beach where I fly the drone up to ~30’ to take pictures of the beach conditions every few thousand feet along the shore. During the flight, I received low battery warnings but was taking very short flights and was planning to stop flying at 15%. Assessing the flight log, there were weak battery warnings with a large percentage of battery life. On the last flight the drone wobbled then fell and tumbled down the dune. The warning indicated that a propeller was lost but it was, in fact, intact; perhaps a motor lost power.


Best guess was a bad battery that was discarded after the flight. The drone suffered minor damage and was repaired


The second incident was an attempt to test Pix4D. I was in a no-fly area near my office. The drone went straight up to the prescribed height and then lost connection with the controller and fell, hard, to the ground.

No idea why it fell. Did something in the no fly zone scramble it causing it to fall? The drone suffered major damage but was repaired/refurbished.




The last incident (06/02/2022) was a flight along a canal to take photos for an orthomosaic to assess algae coverage. I was flying cautiously when I received a obstacle avoidance warning. I asked my VO’s if I was near an obstruction. They said no and I moved on. Then I got another warning so I asked again, “are there birds or anything” the answers were ‘no.’ I was concerned so I intended to get one last shot then return to home to terminate the flight. Before I could do so, my VO saw it fall to the earth. This was the first manual flight since the last incidence but several automated (pix4d) flights had successfully completed (pix4d).

There was a TFR that was to go into effect later that evening but the flight was several hours before the start of the TFR owing to a presidential visit to the Delaware beach. We did successfully fly a mission earlier in the morning without issue. There were thunderstorm forecasted later in the day, so the TFR may have started earlier than the NOTAM indicated.

Did the military zap the drone out of the sky or is the drone a dud?
 
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Hi community,


I have completed numerous flights with my own, personal drone without incident (phantom 3 advanced) but have at three incidences in not so many flights with my work's drone (phantom 4 professional).

This has left me questioning my sanity - do I have bad luck, am I a bad pilot, or was the drone a lemon.

My incidences are described below

The first incident was a mission on the beach where I fly the drone up to ~30’ to take pictures of the beach conditions every few thousand feet along the shore. During the flight, I received low battery warnings but was taking very short flights and was planning to stop flying at 15%. Assessing the flight log, there were weak battery warnings with a large percentage of battery life. On the last flight the drone wobbled then fell and tumbled down the dune. The warning indicated that a propeller was lost but it was, in fact, intact; perhaps a motor lost power.


Best guess was a bad battery that was discarded after the flight. The drone suffered minor damage and was repaired


The second incident was an attempt to test Pix4D. I was in a no-fly area near my office. The drone went straight up to the prescribed height and then lost connection with the controller and fell, hard, to the ground.

No idea why it fell. Did something in the no fly zone scramble it causing it to fall? The drone suffered major damage but was repaired/refurbished.




The last incident (06/02/2022) was a flight along a canal to take photos for an orthomosaic to assess algae coverage. I was flying cautiously when I received a obstacle avoidance warning. I asked my VO’s if I was near an obstruction. They said no and I moved on. Then I got another warning so I asked again, “are there birds or anything” the answers were ‘no.’ I was concerned so I intended to get one last shot then return to home to terminate the flight. Before I could do so, my VO saw it fall to the earth. This was the first manual flight since the last incidence but several automated (pix4d) flights had successfully completed (pix4d).

There was a TFR that was to go into effect later that evening but the flight was several hours before the start of the TFR owing to a presidential visit to the Delaware beach. We did successfully fly a mission earlier in the morning without issue. There were thunderstorm forecasted later in the day, so the TFR may have started earlier than the NOTAM indicated.

Did the military zap the drone out of the sky or is the drone a dud?

Regarding incident 1 -- It's never a good idea to continue to fly with a low battery warning, and equally bad to wait until 15% to decide to stop flying.
Regarding incident 2 -- Why are you flying in a no fly zone?
Regarding incident 3 -- My guess is there was a wire crossing the canal that you and your VO couldn't see from your distance. Wires are almost invisible. And in case you aren't aware of this, TFR time is based on Greenwich Time, not local time. Just an FYI.
 
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Regarding incident 1 -- It's never a good idea to continue to fly with a low battery warning, and equally bad to wait until 15% to decide to stop flying.
Regarding incident 2 -- Why are you flying in a no fly zone?
Regarding incident 3 -- My guess is there was a wire crossing the canal that you and your VO couldn't see from your distance. Wires are almost invisible. And in case you aren't aware of this, TFR time is based on Greenwich Time, not local time. Just an FYI.
Regarding incident 1 -- It's never a good idea to continue to fly with a low battery warning, and equally bad to wait until 15% to decide to stop flying.
Regarding incident 2 -- Why are you flying in a no fly zone?
Regarding incident 3 -- My guess is there was a wire crossing the canal that you and your VO couldn't see from your distance. Wires are almost invisible. And in case you aren't aware of this, TFR time is based on Greenwich Time, not local time. Just an FYI.
Incident 1 - I was getting a warning when the battery was at 50%. I thought may me or another pilot accidently reset the low battery warning to 50% or something to high . . . I attached the flight logs for all of the flights that day so you can see the low battery warning at 50%. I was planning on stopping my flights at 20%.

Incident 2 - My bad. I did not do my due diligence. I saw someone flying in the open space outside my office so I assumed we were just outside the no fly zone. Also, the DJI app typically warns and prevents me from taking off in a no fly zone. I know now never to trust DJI and allows to fully plan a flight even if it is a quick test flight.

Incident 3 - There were no wires of cables visible unless it was fishing line strung up at 140 AGL. We drove along the canal and to the spot the drone landed and saw no obstructions. I am aware that the NOTAM was in UTC, I converted to local EST . . .

-My hypothesis for #2 and #3 is that the first incident may have loosened internal solders which lead to battery connection issues.

I also attached the single flight log for incident 3.

Thanks for your feedback!
 

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  • DJIFlightRecord_2021-02-17.zip
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  • DJIFlightRecord_2022-06-02_[10-42-12].txt
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Regarding incident 1 -- It's never a good idea to continue to fly with a low battery warning, and equally bad to wait until 15% to decide to stop flying.
Regarding incident 2 -- Why are you flying in a no fly zone?
Regarding incident 3 -- My guess is there was a wire crossing the canal that you and your VO couldn't see from your distance. Wires are almost invisible. And in case you aren't aware of this, TFR time is based on Greenwich Time, not local time. Just an FYI.

Whether or not it's wise to continue to fly after a low battery warning (which is set by the operator, btw) or up to or beyond the 15% mark depends on how far from home your drone is, the weather conditions, how experienced a pilot you are and how comfortable you are with risk.
The pilot wasn't flying in a no-fly zone because you can't!
 
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I'll leave it to one of the experts to diagnose your flight log. A few thoughts from me, though:

1. Your drone won't take off in a no-fly zone. Some areas near airports have altitude restrictions - at 60 or 150 metres. If your drone 'hits' a no-fly area during flight, it will stop and prevent you from continuing. It won't drop out of the sky.
2. Sudden loss of power can occur if your battery dislodges during flight - obviously :). This happened to me recently, and I take care to insert my battery correctly. Note that the battery can (and often does) eject on hard impact, so a separated battery at the crash site is not necessarily evidence that it dislodged during flight.
3. Sudden loss of power with the battery still inside is also a possibility. I have experienced this with three P4P drones. I don't know the cause, but what I can say is that if it's happened once with a particular drone, there's a significantly increased chance of it happening again.
 
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I also attached the single flight log for incident 3.
Your data shows a few obstacle avoided notifications, at 3:13.3, 3:28.8 and just before the data ends.

The last second of data from your third incident shows the drone taking emergency action to avoid an obstacle.
The drone was 136 ft up, cruising along at 15 mph at half stick.
AT 220.7 sec you let the right stick centre itself and the drone pitched back to around 25° to put on the brakes and slow down.
At 221.3 when the speed was down to 10 mph the data shows a notification that an obstacle had been avoided.
Then the data shows the drone pitching further back (43.6°), beyond the normal flight pitch angle, rolling 20° to the right, coming to a stop and the data stops there.

What this all means is not certain, but it helps to eliminate some options.

It's not related to an NFZ, if it was, the drone would have autolanded and not lost connection.
It's not because the drone was "zapped" ... it's unlikely that would have brought up an obstacle avoidance message.

It looks like a collision or something else caused the battery to dislodge enough to break contact and gravity took over.
 
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The file contains data for 6 flights.
Do you know which ones were incidents 1 & 2?
The zipped folder are the flights during the first incident. I was taking over and landing on the beach just to fly up to 30' or so the take pictures along the beach, onshore from an offshore location, and offshore from a onshore location - quick flights. The last one is when I lost a propeller.
 
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Your data shows a few obstacle avoided notifications, at 3:13.3, 3:28.8 and just before the data ends.

The last second of data from your third incident shows the drone taking emergency action to avoid an obstacle.
The drone was 136 ft up, cruising along at 15 mph at half stick.
AT 220.7 sec you let the right stick centre itself and the drone pitched back to around 25° to put on the brakes and slow down.
At 221.3 when the speed was down to 10 mph the data shows a notification that an obstacle had been avoided.
Then the data shows the drone pitching further back (43.6°), beyond the normal flight pitch angle, rolling 20° to the right, coming to a stop and the data stops there.

What this all means is not certain, but it helps to eliminate some options.

It's not related to an NFZ, if it was, the drone would have autolanded and not lost connection.
It's not because the drone was "zapped" ... it's unlikely that would have brought up an obstacle avoidance message.

It looks like a collision or something else caused the battery to dislodge enough to break contact and gravity took over.
I was not flying aggressively or irradicably. Unfortunately, I cannot confirm without absolute certainty that I did not hit something but I had two very reliable VO's verify that nothing was in my airspace. I think that it is most likely that the battery connection was an issue.
 
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Whether or not it's wise to continue to fly after a low battery warning (which is set by the operator, btw) or up to or beyond the 15% mark depends on how far from home your drone is, the weather conditions, how experienced a pilot you are and how comfortable you are with risk.
The pilot wasn't flying in a no-fly zone because you can't!
My best guess is a battery connection issue for two and three. The first incident was during a very easy mission where the drone traveled no more then, say 50' away from home. Still not sure why it lost a propeller. It was a cold day and the wind was gusty.

I was mistakenly, my office is not in a no fly zone, it is in Class E airspace.
 
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The battery issue on the first flight appears to be a bad cell. Could still show 50% but not have much true power available. You wouldn't know without checking cell heath but the app knew and warned you. The 2nd issue could possibly be sand in one motor but app thought it was a prop? not sure as prop loss usually makes that motor rev up. Sorry for your loss but sounds like bad luck.
 
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The battery issue on the first flight appears to be a bad cell. Could still show 50% but not have much true power available. You wouldn't know without checking cell heath but the app knew and warned you. The 2nd issue could possibly be sand in one motor but app thought it was a prop? not sure as prop loss usually makes that motor rev up. Sorry for your loss but sounds like bad luck.
Thanks for the feedback. It is possible that sand got in the motor as some gust blew sand and sand was likely kicked up upon landing. Now I know that when I have a strong battery life and get a low battery waring like the ones I got during that flight, I have a bad battery and should terminate the mission.
 

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The first incident was a mission on the beach where I fly the drone up to ~30’ to take pictures of the beach conditions every few thousand feet along the shore. During the flight, I received low battery warnings but was taking very short flights and was planning to stop flying at 15%. Assessing the flight log, there were weak battery warnings with a large percentage of battery life. On the last flight the drone wobbled then fell and tumbled down the dune. The warning indicated that a propeller was lost but it was, in fact, intact; perhaps a motor lost power.
Although the battery was showing 20%, the cell voltages were lower than they should have been for a genuine 20%. Had the battery been sitting for a few days after it was charged?

Towards the end of the last flight from the six, you gave it some left stick to rotate thenthe drone anti-clockwise while flying forward.
At 44.6 seconds things went bad and the drone initially pitched forward steeply and
rolled left 78°, then pitched back 66° as it started fast spinning clockwise andlosing height.

Best guess was a bad battery that was discarded after the flight. The drone suffered minor damage and was repaired
Although the battery was not strong, that wouldn't cause one motor to stop mid-flight.
This was either losing a motor (possibly the right front?) or a collision.
 
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I fly the beach often but have a large landing pad. Blowing sand and corrosion are a constant challenge..and seagulls. The Phantom I use at the beach has a wetsuit that includes covers for the motor holes. Keeps out the sand but doesn't cause it to overheat. Keeps sand out if the battery compartment as well which can kill the contacts. It's designed for rain but works just as well for sand.
 
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I fly the beach often but have a large landing pad. Blowing sand and corrosion are a constant challenge..and seagulls. The Phantom I use at the beach has a wetsuit that includes covers for the motor holes. Keeps out the sand but doesn't cause it to overheat. Keeps sand out if the battery compartment as well which can kill the contacts. It's designed for rain but works just as well for sand.
Good to know. I will look into the wetsuit.
 
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Although the battery was showing 20%, the cell voltages were lower than they should have been for a genuine 20%. Had the battery been sitting for a few days after it was charged?

Towards the end of the last flight from the six, you gave it some left stick to rotate thenthe drone anti-clockwise while flying forward.
At 44.6 seconds things went bad and the drone initially pitched forward steeply and
rolled left 78°, then pitched back 66° as it started fast spinning clockwise andlosing height.


Although the battery was not strong, that wouldn't cause one motor to stop mid-flight.
This was either losing a motor (possibly the right front?) or a collision.
No collisions . . . I have never flown irradicably causing large pitch, roll, or yaw angles. However, immediately before falling for each incident, the drone did what we refer to as the 'death wobble' which may account for the large roll angles.
 
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I see a lot of replies in this thread but I'll give you the benefit of my experience anyway....
The first incident was a mission on the beach where I fly the drone up to ~30’ to take pictures of the beach conditions every few thousand feet along the shore. During the flight, I received low battery warnings but was taking very short flights and was planning to stop flying at 15%. Assessing the flight log, there were weak battery warnings with a large percentage of battery life.
The Go and Go 4 apps have very excellent real-time battery telemetry data. What you're describing is typically a bad cell or several bad cells that will show normal voltage percentage-wise, but will net low-battery warnings. The battery telemetry screen will give you real-time diagnostics, which is parsed down to individual cell voltage. It even has a color palette of green/good, orange/low but safe voltage and red/dangerously low voltage. From now on whenever you get a low voltage warning, hover, open that page and check the battery telemetry data. If you get orange on any of the cells just hovering, that's probably a bad battery. A refresh may fix that, but more than likely not.



The second incident was an attempt to test Pix4D. I was in a no-fly area near my office. The drone went straight up to the prescribed height and then lost connection with the controller and fell, hard, to the ground.

No idea why it fell. Did something in the no fly zone scramble it causing it to fall? The drone suffered major damage but was repaired/refurbished.
NFZ's won't disable the drone in flight. At best it will geofence your drone. At worst, you won't even be able to spin up the propellers.

I haven't looked at your flight logs, but if you are IN an NFZ's or TFR's, the Go(4) app won't even allow the motors to spin up. So I would dismiss the TFR theory.

I'm going to guess erroneous, debilitating WiFi interference was the cause of your crash. It's been my profound experience that it is possible for a DJI drone to interpret some WiFi interference as erroneous commands. I crashed a drone late last year because I didn't follow my own WiFi protocols. I also ignored erroneous drone behavior - all because I was in a hurry. Lesson learned.

Today's world is different from 10 or even 5 years ago. I find there is MASSIVE WiFi activity anywhere within city limits. If your P3 is like my Inspire 1 - and I'm going to guess it is - you don't have a 5Ghz option. So before every flight I check the WiFi situation via the Go or Go 4 app. This has been a most valuable tool. In addition I use the 32-channel hack, which absolutely necessary in today's WiFi saturated world. TWO of my job sites have ZERO (of 32) wide open channels. On both sites channel 12 is *mostly* open with the least interference, so that's the channel I use. In addition, I employ a parabolic signal booster. That's the best 10 bucks you will ever spend. Through profound diligence, I have manage to fly dozens of missions safely in BOTH of these WiFi-saturated mine fields.




The last incident (06/02/2022) was a flight along a canal to take photos for an orthomosaic to assess algae coverage. I was flying cautiously when I received a obstacle avoidance warning.
I disabled Obstacle Avoidance on all 3 of my drones almost the day I got them and I try to keep it that way.

The second or third time I flew my Mavic Pro, I was at 400' AGL over a forest. On the return trip home the OA kept stopping the MP dead in its tracks. At 400' AGL. Ridiculous. This confirmed the legitimacy of my OA trepidation and subsequent protocol. After several unsuccessful attempts to get the drone home, I got into the menu system and completely disabled OA. Some third party apps will reactivate OA. I just go in manually and shut it off. To me, trusting DJI's OA is pure insanity. AT BEST it's marginal. At worst it reports erroneous objects and *causes* crashes. I don't have the time for that. I trust my eyes, my situational awareness and my pilot skills. THAT is what I trust. OA be darned.




Did the military zap the drone out of the sky or is the drone a dud?
No. No government entity will ever do that. The liability would be off the charts. It's possible that someone could build an interference device using a microwave amplifier, but who knows how a drone would react to that. I don't think it would just fall out of the sky, but who knows?

D
 
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