FAILURE AT HIGH ALTITUDE AFTER FIRMWARE UPDATE

[MASINI26]

HI.
I NEED SOME ADVICE FROM YOU.
YESTERDAY I WENT TO A VOLCANO IN MEXICO AND I TRY TO FLY MY DRONE. I TURNED IT ON AS USUAL AND THE DRONE SET THE HOME POSITION. I WAS AT 4356 METERS ABOVE THE SEA LEVEL. I DON'T NOW WHY BUT MY DRONE WENT DOWN AFTER SECONDS OF FLYING. THE WIND WASN'T STRONG.
ONLY MY PROPELLERS BROKE BUT I HAD A REPLACEMENT PAIR AND I TRY TO FLY IT AGAIN, HAVING THE SAME RESULT.
DO YOU KNOW WHAT COULD BE THE PROBLEM? I DONT KNOW IF THE GPS HAVE A MAXIMUM ALTITUDE.

 

[evilfurryone]

Have you flown at that altitude before? If not then it sounds like the air up there is too thin for the drone?

You said you was at 4356 meters which is over 14000 feet and I have not heard anyone flying that high. (Correct me if i'm wrong)

 

[John Shaw]

Helicopters have limits known as HIGE and HOGE. I have no idea what the values would be for the Phantom.
HIGE is the max altitude that you can hover in ground effect (close to the ground - for the Phantom this is probably a few feet above the ground)
HOGE is the max altitude that you can hover out of ground effect (without being close to the ground)
It is easily believable that at the altitude you describe the air is just to thin. When you first lift off and are very close to the ground you are deep in ground effect. As you climb the Phantom just can't generate enough lift do to the thin air.
I don't know the Phantom's numbers but this is effects all helicopter like vehicles.
And in addition if the air is heated by the volcano it just gets worse as hot air is thinner than cool air.

 

[OI Photography]

Helicopters have limits known as HIGE and HOGE. I have no idea what the values would be for the Phantom.
HIGE is the max altitude that you can hover in ground effect (close to the ground - for the Phantom this is probably a few feet above the ground)
HOGE is the max altitude that you can hover out of ground effect (without being close to the ground)
It is easily believable that at the altitude you describe the air is just to thin. When you first lift off and are very close to the ground you are deep in ground effect. As you climb the Phantom just can't generate enough lift do to the thin air.
I don't know the Phantom's numbers but this is effects all helicopter like vehicles.
And in addition if the air is heated by the volcano it just gets worse as hot air is thinner than cool air.

+1

I'd say this is most likely a case of too high and too heavy (and maybe too hot). The negative effects of high altitude that John described are magnified by weight...the heavier the aircraft, the lower the max altitudes.

 

[Chriserl]

Did you do a calibration dance ? I didn't read that you did. This should be done at every different flying site. I'd do it after a firmware update as well

 

[CarlJ]

Was this to appease the Gods?

 

[Silverminer]

I had similar problems at high altitude, >14,000 ft. (shown here https://www.youtube.com/watch?v=WrWDCaBG4xk) Ignore what I say in the video. I went up the next week to test the motor temperatures to see if they overheated using a temperature gun. During the first visit I was able to fly 5 or 6 minutes before crashing (shown here https://www.youtube.com/watch?v=S542SltOqeU). This time, with the new update (which might have been a coincidence) I crashed within 30 seconds. Unfortunately the P2V+ is off the China for repair. A technician I spoke with at DJI felt it might have to do with magnetic interference. I don't know. I've never had a problem at 10,000 ft. but I've had only bad luck at 13,000+. The technician thought one way to test it would be to try to fly at another location on a different mountain. I'd like to do that but my research and development budget is a bit limited (I did order a new P2V+ so I wouldn't be down for the 4 weeks before my broken one returns.) Stupid hobby. I need a 12 step program for this.

 

[CarlJ]

A technician I spoke with at DJI felt it might have to do with magnetic interference.

The tech could be right. Some mountains are really dormant volcanoes, and they can create magnetic fields so powerful that they make their own lighting. Volcanoes also drag metals along for the ride, and that also could be a problem for the Phantom.

I think the problem the OP is describing has already been addressed as the air being thin at high altitudes effecting lift. The lower you are in the atmosphere, the more dense the air, and the greater the lift. The props have to compress the air below them, if there is little to no air, there is nothing to compress. This also creates and area of low pressure above the prop which tugs the craft up. So by flying at that height you're basically defeating the physics that allow the Phantom to fly.

I'm not saying never fly in a mountainous region, we've all seen video of quads flying around them and doing well, but you should be mindful that you could encounter a problem, and if you do, don't repeat the process again expecting a different result.

 

[MASINI26]

THANKS FOR THE REPLYS. I WAS READING ALL YOUR IDEAS AND I THINK THAT THE PROBLEM COULD BE ALL OF THEM.
I FORGOT TO MENTION THAT THE VOLCANO IS NOT ACTIVE, SO THE HEAT IS THE ONLY PROBABILITY THAT IS NOT POSIBLE.
I DIDN'T CALIBRATE THE COMPASS SO, IT CAN BE THAT.
THE MOST RELIABLE IDEA IS THE ONE OF THE MAGNETIC MOUNTAIN BECAUSE I BELIEVE THAT THE DRONE HAD LOSE THE GPS SIGNAL DURING THE FLIGHT. AND I AM NOT SURE BUT IT'S VERY POSSIBLE THAT THE PROBLEM HAD TO DO WITH SOMETHING MAGNETIC OF THE MOUNTAIN.
MAYBE WITH THE NEW DETAILS WE CAN HAVE A CONCLUSION.
WHAT DO YOU THINK?

 

[fenris]

Please take off CAPS-lock. It will make your text much easier for everyone to read.

 

[MASINI26]

Please take off CAPS-lock. It will make your text much easier for everyone to read.

Ok. But do you have any suggestions?

 

[jokeyjon]

I would see the magnetic issue as secondary to the altitude one.

At sea level, air pressure is 1000 millibars. At 4.3km altitude, the pressure is only 600 millibars, so air pressure has dropped 40%. That is ignoring loats of other factors such as air temp and humidity. Your phantom has to work an awful lot harder just to get into the air and the normal fluctuations which are adjusted for by the software to keep the quad stable are going to be exaggerated. I haven't flown my quad at any altitude greater than 2500m, but I wouldn't be surprised to find that the quad is not flyable at 4,300m.

 

[CarlJ]

I would see the magnetic issue as secondary to the altitude one.

At sea level, air pressure is 1000 millibars. At 4.3km altitude, the pressure is only 600 millibars, so air pressure has dropped 40%. That is ignoring loats of other factors such as air temp and humidity. Your phantom has to work an awful lot harder just to get into the air and the normal fluctuations which are adjusted for by the software to keep the quad stable are going to be exaggerated. I haven't flown my quad at any altitude greater than 2500m, but I wouldn't be surprised to find that the quad is not flyable at 4,300m.

I would agree, but doesn't this raise a larger question about the appropriate tool to use at the site of a volcano? Flying is a waste of time, digging is what you wanna do... there's gold in them thar hills! :lol:

If you had all the gold available in the world you could only fill 3.7 olympic sized swimming pools, if you had all the gold that exists on the planet you could fill 24.

 

[fenris]

Please take off CAPS-lock. It will make your text much easier for everyone to read.

Ok. But do you have any suggestions?

My guess, without seeing any video and without a clear description of the crash behaviour, is that it was caused by the altitude... thin air. Did the drone drop like a rock? Or did it slowly descend and then crash?

John Shaw's reply on the first page seems very reasonable to me.

 

[Silverminer]

Please take off CAPS-lock. It will make your text much easier for everyone to read.

Ok. But do you have any suggestions?

My guess, without seeing any video and without a clear description of the crash behaviour, is that it was caused by the altitude... thin air. Did the drone drop like a rock? Or did it slowly descend and then crash?

John Shaw's reply on the first page seems very reasonable to me.

Not sure about MASINI but, in my case, I was able to fly for 5 or 6 minutes before crashing at 14,000 ft.+ I did not observe any strange behavior during that time. I then lost lift fairly rapidly while moving laterally. It seems to me that if it's related only to altitude the issue would be noticeable immediately.

 

[helicopter]

Hi guys,
I often try to fly at high altitude (as living in Kyrgyzstan with a lot of mountains) and face the same problems.
I feel really stable behaviour (always) up to the 2800-2900 meters. On the higher altitudes - it often ends by crash. The control is on place (rotating, side-movings), but somitemes the copter can't stop or reduce its' vertical speed when goes down flying above 3000. And the problem is not linked to compass (calibrated each flight).
I think it is related mostly to the rarefied air...

 

[archersc]

I'm normally operating a Phantom 2 at or near sea level. I'm in the mountains now at 8'800 feet or more above sea level. On my first three flights, the drone suddenly descended very rapidly and uncontrollably -- ending in crashes. Each time this occurred between 8 and 9 minutes into flight. The really unusual thing is that my battery level was still reading 50%+ each time. I get now -- although it seems extreme, my flight times are cut in half or more at this altitude, so I'll be limiting flight times accordingly. What I don't get is why my battery readings aren't properly reflecting this condition. These were three different batteries.

 

[Buckaye]

I thought I had heard that volcanoes have a pretty good magnetic field - especially when active... even though the volcano is not active - I would imagine the magnetic field thing could still be an issue (and as other said - the thinness of the air is also something to consider...

here's a paper I found https://profile.usgs.gov/myscience/uplo ... 871158.pdf

 

[Greyfox51]

As far as altitude and the Phantom is concerned, this might be worth checking out:

http://bestquadcopter.com/everest-dji-phantom/

 

[chapsrlz]

what volcano are we talking about?
im planning a visit to el nevado de toluca.