If they request that then I have no problem producing that for them, although the Bing and Google maps clearly show the location is free if any trees. I would also think that the evidence that Mike provided showing that the throttle input that "cancelled" the altitude rise was me simply trying to land the phantom. If they are any sort of a customer service based company, they should give some leniency to the unfortunate set of circumstances that contributed to this crash.
My P3P crashed, DJI not cooperating
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If they request that then I have no problem producing that for them, although the Bing and Google maps clearly show the location is free if any trees. I would also think that the evidence that Mike provided showing that the throttle input that "cancelled" the altitude rise was me simply trying to land the phantom. If they are any sort of a customer service based company, they should give some leniency to the unfortunate set of circumstances that contributed to this crash.
I was on the bridge of the boat flying the Phantom when the pics were taken. I only moved to the swim platform to bring it in and catch it. I didn't take any pictures at that time.
Yeah. Agreed. Just sort of a fun exercise and for me it has become a learning lesson on the limitations and required skills in certain situations and it's not about responsibility or blame anymore. The attached is how I made my estimation. If bridge clearance is 18ft and I only measured to the roof of the back deck, I think 15ft is a good measurement for that roof. I also googled some Carver 396 images and found someone standing in the back there and it looks like 15ft max. Keep in mind that the yellow lines would actually get a little longer as you go up (perspective change) yet I drew them the same size to be conservative, and I measured to the top of the trees which is actually a little above the horizon. So I think 60 ft is an overshoot of the height. I think those of us who are familiar with shooting photos at altitude would probably agree it's closer to 45 or 50 just by looking at the shot.
Mike
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msinger
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Unfortunately, the most unfortunate thing was that you did not cancel the RTH before it occurred. Had you done that, all would have been just fine.
GadgetGuy
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That's a first! They have always told me that the only file they want is the .DAT file, even though I have always immediately sent them the .TXT file off the iPad, as proof of lack of pilot error!
"We can only use the .DAT files from the aircraft, so ship it in, if you can't get them off the aircraft.” (broken USB port)
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My suggestion would be to turn Smart Go Home OFF, and manage your battery consumption manually. Problem solved!
Well, I made a flight today solely for the purpose of assessing the accuracy of the altitude reading. When I took off, it showed 0 ft. Local conditions were barometer 29.97, temp 88F, and humidity 56%. I took off and raised the AC right next to some palm trees that I know are 35 feet tall. The AC registered 60 feet when level with the tops of the palms. Flew it down to the same height as the top horizontal bar on my lanai (screen enclosure) which I know is exactly 10ft. AC registered 32 feet. Brought it down to where the camera was eye level with me, putting the AC at about my height (5'8"). It registered 22 feet (this is the home location). Landed it in the same spot where I took off and when the landing gear touched the ground, it read 13 ft.
I've come to the conclusion that the altimeter is just not very accurate and it appears that as you increase altitude, the accuracy is off more and more. Maybe that's to be expected since, how accurate can you be with pressure alone? Maybe it uses some calculations to "modify" the barometric pressure altitude based on how the throttle stick is moved, and that drifts over time?
I know one thing. I've learned a lot from this thread. I'm no longer going to raise to 120ft and just take off in my neighborhood, thinking that's a good height to clear everything. With that amount of inaccuracy, I'm doing it by eye from now on.
Mike
I've come to the conclusion that the altimeter is just not very accurate and it appears that as you increase altitude, the accuracy is off more and more. Maybe that's to be expected since, how accurate can you be with pressure alone? Maybe it uses some calculations to "modify" the barometric pressure altitude based on how the throttle stick is moved, and that drifts over time?
I know one thing. I've learned a lot from this thread. I'm no longer going to raise to 120ft and just take off in my neighborhood, thinking that's a good height to clear everything. With that amount of inaccuracy, I'm doing it by eye from now on.
Mike
Very interesting results Mike ! Thank you again for your determination in figuring out what went on here. Its interesting from my perspective having experienced the crash to watch the technical analysis by the experts and compare the results to my observations. If DJI ends up accepting even some responsibility here, I owe you big time !
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Sure. Here ya go. I also took the attached photo from 96.8 feet (trying to match the OP's 96.5 as close as I could). Based on my observations during the flight, it was probably closer to 70 or 75 feet but anyway... here are the files...
Mike
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The 1st thing I saw when looking at the data from the "Rude Boy" aircraft was two errors "SpeedErrorLarge" and "CompassErrorLarge". Both due to an impact.
I checked the coordinates and found the aircraft to hit a tree limb 7 seconds after being commanded to Go Home by the app settings. And during those 7 seconds the operator worked the R/C Sticks over pretty good. I feel like it's because of the Stick activity is why DJI dumped the claim. They probably felt like the aircraft did what is was suppose to throughout the event.
I will goto that area this weekend with the proper equipment and plot the exact location of impact. The Phantom DID NOT hit a tree.
Your direction is also wrong. The course you suggest isn't heading towards the home position. If you plot the route correctly, that tree is nowhere near the flight path.
The bigger issue here is the incorrect altitude readings causing the Phantom to fly off at a much lower altitude than it was supposed to. Had it actually flown off at 54 feet, it would have easily cleared that dwarf tree in your diagram and stayed clear of the rocks and water.
Your direction is also wrong. The course you suggest isn't heading towards the home position. If you plot the route correctly, that tree is nowhere near the flight path.
The bigger issue here is the incorrect altitude readings causing the Phantom to fly off at a much lower altitude than it was supposed to. Had it actually flown off at 54 feet, it would have easily cleared that dwarf tree in your diagram and stayed clear of the rocks and water.
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msinger
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I noticed that too. It would be interesting to know what the OP was attempting to do during that time.
Simple answer..... I was trying to regain control of my AC. I was bringing it in to land and I suddenly lost control and it takes off heading directly towards the rocks ! There was nothing to suggest that RTH had engaged.
Interesting stuff here. I decided to see how much my barometer changes. Short flight, about 3 minutes. Temp 93 degrees, 65% humidity. 29.90 inches barometer. Took off, hovered with P3P at eye level. Altitude read 6 feet as did the VPS. Flew up to 400 feet, hovered about a minutes, brought it back down. Hovered at eye level. Again, VPS said 6 feet, altimeter said 3 feet. Upon landing, altimeter read -3 feet. Easy to see how much the altimeter can drift in these things, and that on a very short flight, simply up to 400 feet and back down. I will be paying much closer attention to altitude readings in the future after longer flights to see how much this drifts, but I think its probably very reasonable that over the length of a full battery to see a 40+ foot disparity.
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We are referring to the time period after it passed your boat and was heading toward the rocks. It looks like it took 8 seconds to get to the crash site. During that time, you had the throttle stick in the full down position for a while.
I'm not for a moment suggesting there weren't mistakes on my part. Yes, I panicked and was trying my best to regain control of the AC. This is a reasonable response considering my inexperience and the reaction time I had. That said, the AC also didn't function as it should have. The altitude readings were way off which also contributed to the crash. As others have stated, giving the OP the ability to cancel the RTH altitude rise while still allowing the AC to fly off at a reduced, potentially unsafe altitude is faulty programming logic that will cause more crashes. In my case, due to very unlucky timing, the auto RTH engaged as I was applying negative throttle attempting to land the aircraft. This resulted in the AC flying off at a reduced altitude further aggravated by incorrect altitude readings by the AC itself.
Also during that time you CSC briefly. Had that came into play you would not have any wrong altitude concern. Just another 10th of a second....
I realize my direction was not exact as I forgot to mention that I had put it there just to give a general idea what I was referring to. But, based on what I see in the data there is noway you will get me to change my thinking on the A/C coming in contact with something just before tumbling down.
It did come into contact with something... The rock, then cartwheeled into the water. I will post the exact GPS coordinates this weekend of the impact location. Stay tuned....
Will my iphone be accurate enough? I can use the compass app and locate the exact spot outlined in the logs
Will my iphone be accurate enough? I can use the compass app and locate the exact spot outlined in the logs
I'm curious where in the log you saw a CSC. I looked for that but didn't see one. As I understand it, you'd have to see 10,000 in all 4 control columns to initiate a CSC. I don't remember the sign (neg or pos) but I believe it's three -10000's and one 10000. But in any case, I didn't see 10,000 (positive or negative) in all 4 control columns at any point during the flight (except on takeoff where you'd expect it).
Mike
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