175 feet straight down slamming onto a frozen lake!

[Geoelectro]

Today's electronics are typically very reliable. We have and depend on very sophisticated electronics every day. Phones, computers, home networks etc. If something goes wrong, maybe totally explainable, you usually can just reset it or turn it off and back on again and all is great.

However, with a flying machine, everything needs to be working right just to keep it off the ground. Gravity is constantly pulling against it and all the circuits, motors, batteries and firmware are working together to keep it afloat. If something does fail, well, gravity does it's thing.

I had a P2 fall straight down from about 100' for no reason. There was a message about the battery but I was using a phone as the display and couldn't read it fast enough. I remember it saying to fly safely. I was just hovering straight up when it happened. It bent the RP gimbal which I was able to straighten out. It broke the GPS as it landed upside down. That craft was repaired but I was always extra cautious about flying it and didn't trust it like I used to.

My P4 has been flawless. However, if it did something weird happened that was unexplainable I would loose confidence in it as well.

One attitude to take is this. Do everything you should to insure your craft is running properly. Regular checks etc. Then, just fly. Understand it may crash or go lost but until it does, your flying. I wanted to fly a certain bridge last year that was going to be a 3 mile trip over water. I knew it was possible and labored over the mission for weeks. Once I came to the place of realizing that either I come back with no craft, or with an epic video and I'm OK with either, I went and got the epic video. When the P4 was over land again THAT was a great feeling!

Geo

 

[The Famous]

Well said Geoelectro! Video I did of Watkins Glen State Park. Ending is awesome! Good thing the battery didn't fail here! Would have nothing to send to DJI! Tony Vickio

 

[fatmaggots]

I've examined and analyzed enough flight logs here to know that user error is unquestionably the predominant reason for crashes and "flyaways". I'm not sure how you got the opposite impression.

Perhaps I got it wrong, my impression is from reading all the analysis from the experts on this forum. If as you say, from your reviews it is predominantly user errors, what have you found as the common thread for these crashes and flyaways?

 

[sar104]

Perhaps I got it wrong, my impression is from reading all the analysis from the experts on this forum. If as you say, from your reviews it is predominantly user errors, what have you found as the common thread for these crashes and flyaways?

Flying in high winds, flying behind terrain and buildings, incorrectly installed props, improperly latched batteries, flying too far and ignoring low battery messages, takeoff from magnetically distorted locations, autonomous missions with inadequate programmed altitude etc. are the common user errors that I've seen. There is no one single cause.

 

[MotorCycle-Man]

How about a good preflight check at home....look it over good for things that would affect safe take off and flight ..Thats a great post above mine..and i have a hearing problem and i wear a set of the small ear plugs plugged in to my tablet so i can hear ever thing from home point recorded to low battery warning and critical low battery warnings to...By that time im landing....have fun as you safely take to the wide Open skys above !

 

[fatmaggots]

Thanks. Except for unexpected high winds and magnetically distorted locations, I believe that every other example you gave can be user controlled. I’m going to get back up in the sky in the summer, I guess my bad experience has had me caged.

 

[The Famous]

I'll tell you one thing! I purchased Drone insurance from State Farm ($63.00) about 2 months ago. Yesterday was paid in full for a new drone! Takes a lot of worry out of flying!

 

[randun41]

Thanks. Except for unexpected high winds and magnetically distorted locations, I believe that every other example you gave can be user controlled. I’m going to get back up in the sky in the summer, I guess my bad experience has had me caged.

IMHO even the 2 reasons you stated are also DIRECTLY user controlled. If already moderately windy,expect greater winds at higher elevations. If magnetically distortions, move to another launch location to solve that issue! We have all read what can occur when taking off in such distorted fields can do. Fly SMART, it helps you enjoy the moments better!!

 

[WBN3]

Flying in high winds, flying behind terrain and buildings, incorrectly installed props, improperly latched batteries, flying too far and ignoring low battery messages, takeoff from magnetically distorted locations, autonomous missions with inadequate programmed altitude etc. are the common user errors that I've seen. There is no one single cause.

I've read many of your posts, and I definitely agree with your assertion. Your list above seems pretty complete, but just curious how you've diagnosed improperly latched batteries from the flight records... had a crash experience with my son flying, and wondered whether it might have been due (in part at least) to loss of the battery.

I think you could also mention that the impressions formed from reading anything here on PhantomPilots are biased with respect to overall flight success - the predominant reason people post here is because they need help. The people who are flying successfully aren't registering their successes nearly as frequently - although we do see an occasional video shared. It would be nice to have actual statistical data on losses vs. mission hours completed.

 

[sar104]

I've read many of your posts, and I definitely agree with your assertion. Your list above seems pretty complete, but just curious how you've diagnosed improperly latched batteries from the flight records... had a crash experience with my son flying, and wondered whether it might have been due (in part at least) to loss of the battery.

I think you could also mention that the impressions formed from reading anything here on PhantomPilots are biased with respect to overall flight success - the predominant reason people post here is because they need help. The people who are flying successfully aren't registering their successes nearly as frequently - although we do see an occasional video shared. It would be nice to have actual statistical data on losses vs. mission hours completed.

The DAT logs don't directly indicate that the power loss was a battery disconnect - all you see is a sudden and very rapid voltage drop which could also be an internal connection issue. However, there have been a number of cases where the aircraft is recovered and not too damaged, and it powers up just fine when the battery is replaced, suggesting no physical failure in the power system. In other cases it won't and broken connections are found on one of the boards, for example. Not absolutely conclusive, but pretty strong evidence.

 

[The Famous]

In my case the battery did not come out and no lights were blinking. When I got home I tried firing up the battery and to my surprise the familiar sound as the drone came to life. Just one prop wiggled as the others were jammed onto to the motors. The battery had clearly shut off as it did not pop out.

 

[sar104]

In my case the battery did not come out and no lights were blinking. When I got home I tried firing up the battery and to my surprise the familiar sound as the drone came to life. Just one prop wiggled as the others were jammed onto to the motors. The battery had clearly shut off as it did not pop out.

That's correct - your case was clearly not a battery ejection - it appeared to be a faulty battery cell.

 

[WBN3]

The DAT logs don't directly indicate that the power loss was a battery disconnect - all you see is a sudden and very rapid voltage drop which could also be an internal connection issue. However, there have been a number of cases where the aircraft is recovered and not too damaged, and it powers up just fine when the battery is replaced, suggesting no physical failure in the power system. In other cases it won't and broken connections are found on one of the boards, for example. Not absolutely conclusive, but pretty strong evidence.

Good info... I know the data is captured at a pretty high frequency so any loss of contact with the battery terminals might display as a voltage drop for one or two data points prior to total loss of power. I assume there is some capacitance in the power circuitry that would allow it to write data briefly following loss of contact, but I would suppose that's very brief.

Thanks again for your contribution to this forum. You and the others who do such detailed evaluation of flight logs are truly the best of the best.

 

[BudWalker]

but just curious how you've diagnosed improperly latched batteries from the flight records... had a crash experience with my son flying, and wondered whether it might have been due (in part at least) to loss of the battery.
....

We already looked at this. The voltage deviation was probably due hitting something at the very end. Take a look at this post from your thread back then.

P4 disconnected in flight, found with battery missing

In cases where the battery either comes loose or has some type of failure there is about a 50% voltage drop.Like with this incident

Phantom 4 Advanced dropped from the sky

 

[John Locke]

Flying in high winds, flying behind terrain and buildings, incorrectly installed props, improperly latched batteries, flying too far and ignoring low battery messages, takeoff from magnetically distorted locations, autonomous missions with inadequate programmed altitude etc. are the common user errors that I've seen. There is no one single cause.

You can add that good list of errors...... taking off with a cold battery. If that battery was exposed to freezing temperature very long, primarily before take-off, that can impair the chemistry of the outside cell that's exposed to the cold the most. In the battery plot posted it appears the RED LINE CELL #1 cell dropped below 3.0V (it went off the chart low). I've always heard the TI microcontroller inside the battery has a 3.0V cutoff, not 3.2V. If any cell gets below 3.0V, the "smarts" will turn off the battery, whether it's flying or not (not too smart if you ask me).

In cold climates it's essential that you enable the battery cell voltage level to display in the Go4 screen (upper right corner). There's a setting in for that. That voltage, when displayed, is always the lowest voltage of each of the 4 cells. If you get close to 3.0 V you are in dangerous range and you should gingerly RTH as smooth as possible WITHOUT giving it full throttle. I would worry at 3.3V because that's abnormal for P4/P4P craft to get that low on a typical flight. When flying in warm weather (70C), I will often have 3.6V readings for the lowest cell when the battery is depleted to 25%. This changes in freezing cold weather if the battery is allowed to get very cold before take-off, because LiPo chemistry likes warmer temps.

 

[sar104]

Good info... I know the data is captured at a pretty high frequency so any loss of contact with the battery terminals might display as a voltage drop for one or two data points prior to total loss of power. I assume there is some capacitance in the power circuitry that would allow it to write data briefly following loss of contact, but I would suppose that's very brief.

Thanks again for your contribution to this forum. You and the others who do such detailed evaluation of flight logs are truly the best of the best.

The motor voltage data are recorded at 25 Hz (possibly 50 Hz on some aircraft), and the logging continues down to around 6 V. It takes of the order of 100 ms to fall to that level, so we see 3 or 4 data points on the way down:

 

[With The Birds]

If the battery had commenced the auto discharge cycle before you flew there is a good chance the cells are fine. Flying on a pack that has entered auto discharge is asking for trouble.

The auto discharge works by switching the balance bleed resistors into circuit (seperate resistor for each cell). The resistor tolerances mean that the cells may be presented with different loadings and you end up starting your flight with the pack imbalances. The small imbalance becomes a larger one quickly as the low cell has to provide more current and is depleted at a faster rate.

 

[WBN3]

We already looked at this. The voltage deviation was probably due hitting something at the very end. Take a look at this post from your thread back then.

P4 disconnected in flight, found with battery missing

In cases where the battery either comes loose or has some type of failure there is about a 50% voltage drop.Like with this incident

Phantom 4 Advanced dropped from the sky

Yes, I knew that wasn't the cause of our incident, nor of the OP's... was actually hoping to avoid any discussion of or references to that series of unfortunate events (lol). Photobucket has made a mess of that thread, but that's a completely different issue.

I was just curious how the flight log would capture information that is the tell-tale of a loss of power when it depends on said power to record its log. I think it's more like Occam's razor... but I wanted to see what that signature might look like. sar104 confirmed my suspicion...

 

[The Famous]

How do I do the proper maintenance on my batteries?

 

[Ebjerke]

I'll tell you one thing! I purchased Drone insurance from State Farm ($63.00) about 2 months ago. Yesterday was paid in full for a new drone! Takes a lot of worry out of flying!

Good for you on the insurance! I have State Farm but they don’t offer that insurance in California. So I thought I could put it on my personal items policy like my other camera gear. Nope. My agent told me that State Farm is discontinued this insurance because they got way too many losses and claims. From drones I mean. Does anybody remember the name of the smaller insurance company that sold drone insurance for like 130 bucks a year?