I finally lost my Phantom - not a "flyaway"

[Gnormand]

been flying since April...reading posts all over the web about pilots losing their birds. I remember thinking to myself how lucky and blessed I was....and then...4 hours later, my P3P acquired a mind of its own...would not
respond to any input...flew about a mile North of me and disappeared. It is truly a disheartening event.

Attached is the flight log...would anyone who knows how to read these things tell me if I did anything I shouldn't have done?

 

[PaulSouthport]

Here is the log in phantomhelp: Phantom Log Viewer - PhantomHelp.com

 

[Rick Jessen]

Did you turn off your tx that will send it home? Did you have a home lock before you left?

 

[PaulSouthport]

there are a lot of class d airspace warnings, looking at the KML you appear to have flown over then past a tall building, past what appear to be 2 microwave antennas.

 

[cstout]

It also looks like you were flying at a good fast speed on the way out and when it attempted to return it struggles to get above 4mph all the while getting further away. I'm guessing wind on this one...

 

[msinger]

my P3P acquired a mind of its own...would not
respond to any input

It wasn't able to obey your commands since the signal was blocked by a tall building.

 

[Sinisalo]

I am no pro but it looks like you flew between two buildings, got some class d airspace GEO warnings, and then lost signal. Also it looks like cell 1 in your battery is bad, it had lots of major deviations. Your battery was 24 percent at about a mile out so I don't think there is any chance it returned to home right into the side of one of those buildings but more than likely it attempted to land once it reached your pre programmed critical voltage level. If it was really cold outside, that combined with the bad cell, I don't think your phantom would have been able to descend from that height in time to land safely. Time to upgrade to a Mavic, P4, or P4P.

 

[Quamera]

It wasn't able to obey your commands since the signal was blocked by a tall building.

View attachment 71994

msinger, it really is an amazing service you provide to help people find lost Phantoms. Misguided souls sometimes disagree with you because they have their own set ideas but have to eat humble pie eventually when their baby turns up exactly where your graphic said it would. In most cases the pictures also show us in detail exactly what not to do, as the old saying goes, better than 1000 words. Many male brains glaze over when faced with pages of instructions but they can work out a graphic fairly quickly.

Rather than repeating it all again is there a link that can tell us what the colors and symbols mean on the track. A fair bit is obvious but knowing what the colors meant would fill in some gaps.

O

 

[msinger]

is there a link that can tell us what the colors and symbols mean on the track

The link to the log can be found in the 2nd post above. In Firefox, you can hover over those points to see what they mean. The line colors are just showing when the battery voltage is low or the battery cell deviation is high.

 

[Quamera]

The link to the log can be found in the 2nd post above. In Firefox, you can hover over those points to see what they mean. The line colors are just showing when the battery voltage is low or the battery cell deviation is high.

Thankyou msinger, I'm sure I speak for everyone here when I say that we are very grateful for the time you put in here.

 

[mandalay]

been flying since April...reading posts all over the web about pilots losing their birds. I remember thinking to myself how lucky and blessed I was....and then...4 hours later, my P3P acquired a mind of its own...would not
respond to any input...flew about a mile North of me and disappeared. It is truly a disheartening event.

Attached is the flight log...would anyone who knows how to read these things tell me if I did anything I shouldn't have done?

Sorry to hear about your loss. Have you tried to look for it somewhere near St. Francis St and St. Joseph St?

 

[Quamera]

The link to the log can be found in the 2nd post above. In Firefox, you can hover over those points to see what they mean. The line colors are just showing when the battery voltage is low or the battery cell deviation is high.

Well I have just spent an interesting hour examining the flight log and the longer I look the more I see especially when combined with the google map pic. I won't go through it all because it would take too long and would bore many of you to tears but previous posters seemed to have nailed this one and in hindsight the warnings were there for the pilot to see before his Phantom was lost.

 

[Meta4]

been flying since April...reading posts all over the web about pilots losing their birds. I remember thinking to myself how lucky and blessed I was....and then...4 hours later, my P3P acquired a mind of its own...would not
respond to any input...flew about a mile North of me and disappeared. It is truly a disheartening event.

back in the early days of ready to fly drones (P1 & P2) you could come home without your Phantom and tell everyone that it flew away and they would believe you.
Phantoms got a reputation for this which caused more people to believe that their Phantom would eventually fly away.

But since the P3, Phantoms have a flight data recorder that shows actual flight data.
Investigating cases of Phantoms flying away shows that in almost all cases, the Phantom did exactly what it was programmed to and the owner's inexperience, disorientation or plain dumb mistakes are to blame.
This Phantom didn't fly away at all and a pilot of average experience should have been able to bring it home.
I've changed the thread title for you to something more accurate.

Attached is the flight log...would anyone who knows how to read these things tell me if I did anything I shouldn't have done?

The most obvious thing is the wind speed that day.
The Phantom is up nearly 600 feet where the wind is much stronger than on the ground.
You flew your Phantom away downwind in a strong wind which will always mean a hard slog back with a headwind.
This is a huge mistake which is a factor in many reported "flyaways"
AT 3:43 with the Phantom only 740 feet away you initiated RTH and watched your Phantom go backwards at 3-4mph until it was 4300 feet away and signal was lost because a tall building blocked things.
You tried a couple of times to power into the headwind but that only slowed the drift and didn't reverse it.
You left your Phantom up high in a wind that was blowing harder than RTH could fight.
Had you brought the Phantom down out of the worst of the wind as well as pushing the right stick to kick up the speed you would still have your Phantom.
Of course the easiest thing would have been to prevent the incident by flying upwind and not so high in the first place.

 

[Quamera]

Did you turn off your tx that will send it home? Did you have a home lock before you left?

Firstly Gnormand I hope you don't feel I am criticizing you, everyone can be wise in hindsight and I do apologize if I am guilty of that now or in pervious posts. I hope you find your P3P in reasonable condition and it flies again (with a fresh battery, how old was the one in it?). Good luck and if its any comfort your misfortune is probably helping hundreds of others on this forum, its certainly helped me.

From my inexperienced reading of the log turning off the tx wouldn't have done any good at all. There was a brisk south to south west wind blowing above 500 ft and the Phantoms battery management had to limit the power output to save the battery from failing due to a bad cell. Even though RTH was enabled for most of the last half of the flight it had no chance against the wind at that height.

By the time it was blown out of range (partly due to a big block of concrete, glass and steel in the line of sight) at 10:31 and 26% of a crippled battery remaining, heading NE over 4000 ft away only a miracle was going to save it. That being said it would definitely be worthwhile to estimate how much further it would have gone on the current path before auto land was enabled because of a low battery then a further estimate of how far NNE it would have been blown during the auto land attempt before the final plummet.

 

[Quamera]

Firstly Gnormand I hope you don't feel I am criticizing you, everyone can be wise in hindsight and I do apologize if I am guilty of that now or in pervious posts. I hope you find your P3P in reasonable condition and it flies again (with a fresh battery, how old was the one in it?). Good luck and if its any comfort your misfortune is probably helping hundreds of others on this forum, its certainly helped me.

From my inexperienced reading of the log turning off the tx wouldn't have done any good at all. There was a brisk south to south west wind blowing above 500 ft and the Phantoms battery management had to limit the power output to save the battery from failing due to a bad cell. Even though RTH was enabled for most of the last half of the flight it had no chance against the wind at that height.

By the time it was blown out of range (partly due to a big block of concrete, glass and steel in the line of sight) at 10:31 and 26% of a crippled battery remaining, heading NE over 4000 ft away only a miracle was going to save it. That being said it would definitely be worthwhile to estimate how much further it would have gone on the current path before auto land was enabled because of a low battery then a further estimate of how far NNE it would have been blown during the auto land attempt before the final plummet.

Sorry, while I was writing this (very slowly) Meta4 beat me to it so we have doubled up, thankfully we agree on most points.

 

[Chesapeake]

Firstly Gnormand I hope you don't feel I am criticizing you, everyone can be wise in hindsight and I do apologize if I am guilty of that now or in pervious posts. I hope you find your P3P in reasonable condition and it flies again (with a fresh battery, how old was the one in it?). Good luck and if its any comfort your misfortune is probably helping hundreds of others on this forum, its certainly helped me.

From my inexperienced reading of the log turning off the tx wouldn't have done any good at all. There was a brisk south to south west wind blowing above 500 ft and the Phantoms battery management had to limit the power output to save the battery from failing due to a bad cell. Even though RTH was enabled for most of the last half of the flight it had no chance against the wind at that height.

By the time it was blown out of range (partly due to a big block of concrete, glass and steel in the line of sight) at 10:31 and 26% of a crippled battery remaining, heading NE over 4000 ft away only a miracle was going to save it. That being said it would definitely be worthwhile to estimate how much further it would have gone on the current path before auto land was enabled because of a low battery then a further estimate of how far NNE it would have been blown during the auto land attempt before the final plummet.

From what I've been reading, after about 100 hrs. the batteries are no longer reliable, if they last that long?

 

[Gnormand]

Did you turn off your tx that will send it home? Did you have a home lock before you left?

what does turn off tx mean? I did not do anything differently or turn off anything that I am aware of. Yes, controller said "home point established"

 

[Quamera]

what does turn off tx mean? I did not do anything differently or turn off anything that I am aware of. Yes, controller said "home point established"

He meant turning off your remote control, as a last resort if the Phantom isn't responding and you turn off the remote then the Phantom will obviously loose the signal (because there isn't one to find). After 3 secs the RTH will activate and if everything is in your favor, bingo it will return home.

It wouldn't have done you one bit of good, as noted in previous posts RTH was already activated (several times) and the wind at height, dying cell 1 (and suspect cell 4) as well as the building had you beaten although the Phantom still may have been saved if the height had been reduced earlier in the flight.

As said before its easy to be wise in hindsight and many of us have learnt valuable lessons from your misfortune. Have you tried to do some drift predictions from the Phantom's last known position.

 

[Quamera]

From what I've been reading, after about 100 hrs. the batteries are no longer reliable, if they last that long?

I have been shadowing this forum for a couple of weeks and have not actually seen much on battery life, in general terms Lithium chemistry batteries have their lives measured in cycles with 300 to 500 cycles being the norm for quality cells dependent on Depth of Discharge and time at temperatures above 30 Deg C (especially if fully charged). Age does come into the equation but is less relevant than Cycles, DoD, time at high temps and time at high (above 3.92V or 58% capacity) or low voltage.

Luckily DJI and other manufacturers using Lithium batteries have decide that humans shouldn't be left in charge of these batteries and have introduced some smart electronics to extract the best performance. I am very impressed with DJI monitoring the individual cell voltage and its loading because any battery pack is only as good as its weakest link and to know when one cell is failing is invaluable when judging the suitability of an aging battery for future use.

One interesting figure to ponder is if you are looking for maximum number of cycles from your battery pack is that by lowering the maximum charge voltage per cell by 0.1V you reduce the stored power by 14% and double the number of cycles in the expected life of the battery and the opposite is also true. Manufacturers have decided that 4.2V per cell is the best balance between stored power and battery life but you can adjust that if you want to according to your own priorities.

 

[With The Birds]

I have been shadowing this forum for a couple of weeks and have not actually seen much on battery life, in general terms Lithium chemistry batteries have their lives measured in cycles with 300 to 500 cycles being the norm for quality cells dependent on Depth of Discharge and time at temperatures above 30 Deg C (especially if fully charged). Age does come into the equation but is less relevant than Cycles, DoD, time at high temps and time at high (above 3.92V or 58% capacity) or low voltage.

Luckily DJI and other manufacturers using Lithium batteries have decide that humans shouldn't be left in charge of these batteries and have introduced some smart electronics to extract the best performance. I am very impressed with DJI monitoring the individual cell voltage and its loading because any battery pack is only as good as its weakest link and to know when one cell is failing is invaluable when judging the suitability of an aging battery for future use.

One interesting figure to ponder is if you are looking for maximum number of cycles from your battery pack is that by lowering the maximum charge voltage per cell by 0.1V you reduce the stored power by 14% and double the number of cycles in the expected life of the battery and the opposite is also true. Manufacturers have decided that 4.2V per cell is the best balance between stored power and battery life but you can adjust that if you want to according to your own priorities.

So reduce your terminal SOC by 100mv and fly your battery down to 11% instead of 25% (accounting for the 14% you haven't put in). Do you double your life cycles then?