ianwood said:
Jaybee,
If I am counting correctly, yours seems to be the second P2 on this forum that has flown away (the rest are P1 and P2V reports). The first one sounds like it was having issues right out of the box (4 fly aways!). If you don't mind me asking, what are the details of yours? ...
Hey buddy, this is a long post but hope it may help others.
How many times had you flown it?
About 8 times. Makes me a novice user, sure, however I am good with technology and fully understand what I am doing in terms of checklists and common sense. Knowing the Phantom has the failsafe feature while flying in GPS mode provides a level of confidence in terms of alleviating natural concerns about flying at a reasonable altitude.
Did you crash it all?
Nope.
Any modifications? Did you open it up at any point?
Nope, only the Zenmuse.
Where were you? Any potential sources of interference in the area?
None, no power lines, source of EMI etc. I even checked where all the mobile antennae are near the area, the nearest was apx. 800m away from my start location and away from the flight area. Here is the mobile antennae stats if anyone is interested:
– Microcell
– Height of Antenna: 8.3 Metres
– Frequency Range: 1800 MHz
– Transmitter Power: 16.9 dBW
– Maximum licensed power: 32 dBW
– Type of Transmission: GSM
The common town/city microcells here in the UK are all below 2000Ghz anyway, so they shouldn’t have any impact as I understand it (more on this below).
Had you flown there before?
Yes, twice.
When did you last calibrate compass or IMU?
The compass; when I first got the Phantom in late December. And the last time I was at this location (previous flight last week). The IMU; never. I’ve never had the need to, it’s always flown very nicely. In fact, the hover on this particular day was the best I’d every seen it — was so stable, almost not moving. No doubt due to the low 4mph wind speed on Sunday.
How did it fly away? Straight off in one direction? Was it hovering just before or after you lost control? How well could you see it?
I had eyes-on and line of sight, but all of a sudden it didn’t respond to the Tx when I tried to bring it home and continued to fly west of my location. It was then out of sight, gone.
About 30 secs or so after this, I killed the Tx and tried to work out where it had gone. It was fairly high the last time I saw it, apx. 30-50m and apx. 300m north of it’s home location. As we know, the advertised range is 1000m in open spaces. Plenty of people seem to have flown out of visual range with FPV and the Phantom engaged RTH when out of range.
If it had entered the failsafe mode when I killed the TX it had plenty of height and was in range / battery for RTH. This is the crux of the problem, for whatever reason this just didn’t happen.
What mode were you flying in? Did you try switching modes when you felt it was not in your control?
GPS as always. No, I killed the TX to try and get the thing home.
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I understand anyone with anxiety, it’s natural to feel like that, especially when we hear that Phantoms have flown away. The cost is fairly significant too with a GoPro 3+ Black, memory card, and gimbal. My setup cost me around £960 ($1577). To be honest I felt a bit of anxiety to begin with but, as any Phantom owner would, I thought my care and attention to the important details would prevent a flyaway caused by human error.
"If I make sure to stick to the check list and didn’t make any glaring mistakes, everything will be fine as the failsafe is only a Tx power-off away." This is a comforting thought and a major selling feature, Without this feature, it’s far more likely things could go wrong. This is why it’s obviously massively disappointing if the failsafe fails to do it’s job.
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Here’s a list of possible human error causes and how they relate to my particular situation:
Not waiting for the rapid green lights then steady green before take off
I’m 100% sure I the sequence was correct as per usual.
Flying straight off without testing hover and responsiveness
I always make sure I test the hover / responsiveness and fly about nearby for a couple mins to ensure everything is in order before getting to any altitude.
GoPro WiFi ON
I’m 100% sure mine was off as always.
S1 is in GPS mode not ATTI
I’m 100% sure mine was set to GPS.
S1 gets flipped out of GPS mid-flight
I am 100% sure this didn’t happen.
Flying in strong winds
As I mentioned, on this day I had the calmest winds out of any previous flight. It was around 4 mph according to weather reports and I can verify that there was no wind or sudden gusts and that the Phantom was extremely responsive and stable, even at a high altitude.
Flying near a strong source of EMI
None in the area (see above regarding a single mobile antennae at ground level, well away from the point when I lost control).
Compass calibration required (from the manual):
(1) When Compass Data is abnormal, the LED flight indicator will blink alternating between red and yellow.
I am 100% sure my Phantom wasn’t blinking red/yellow
(2) Last compass calibration was performed at a completely different flying field/location.
The last time I flew was the same location.
(3) The mechanical structure of the aircraft has changed, i.e. changed mounting position of the compass.
I’d changed nothing here.
(4) Evident drifting occurs in flight, i.e. the aircraft doesn’t fly in straight lines.
Flight and hover was very stable.
Flying with a low battery
I am 100% sure I had a full battery to begin with. Before my last flight path, I’d flown the Phantom back around to check the battery. It had 3 green lights, this is around 2-4 mins before it flew off.
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Possible reasons for this fly away
• Something messed with the compass and GPS causing the Phantom to fly away. From my research, many seem to dismiss cell towers cause problems. However, the Phantom manual states:
"6.1 (5) Try to avoid interference between the remote controller and other wireless equipment. (No base stations or cell towers around).” The video with Colin Guinn advising how to avoid flyaways also suggests to avoid cell towers. I’ve read suggestions that cell companies actually use drones to check their towers (the big ones). Others suggest flying near cell transmitters with 2.4Ghz drones doesn't matter (check RC Groups for more). Clearly we need more conclusive info. Either way, I almost certain this has anything to do with my flyaway.
• The system crashed, i.e, for whatever reason the code running had an error and the failsafe didn’t engage. Quite plausible. Here’s an interesting
point of view from
http://www.rcgroups.com/forums/showthread.php?t=1872000&page=66
• The battery ran out before I killed the Tx: impossible, it had 3 lights around 2-4 mins before I lost control.
• Prop came loose / fell off. Hardly likely with the self-tightening mechanism, and considering the apparent stability of my Phantom in this instance.
• iPhone / smart phone in pocket causes Tx issues. No idea here, but I’ve never had any issues myself. If there was a problem, I’d expect the Phantom to RTH as it would with a broken / obstructed Tx signal.
• GoPro malfunction causes it to switch it’s WiFi on. Never heard of such a situation, but I guess it could happen in theory.
• A malfunctioning / faulty motor. This would certainly cause unexpected flight behaviour. I’d suggest that if things are normal at the start of a flight and if you’ve not crashed prior to taking off again, this is highly unlikely.
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Preventative measures going forward
• Install some form of GPS tracker. Test fully, even while in-flight so if the worst happened you could kill your Tx and quickly phone the tracker to try and get a location, especially if out of visual / or heading out of visual at a high altitude. Test often.
• Mark the Phantom with contact details. You never know, someone may find a lost craft and get in touch. Easy to do.
• If the concern / fear of loss is so great, simply don’t fly high and far away. Keep the craft nearby. Not going to be much fun, but a safer bet.
• Only fly in the countryside where you are surrounded by fields for at least 1000m. Same as above.
• Don’t use the stock controller. I don’t have any experience with this one, but many suggest the third party controllers are far more reliable. Either way, I’d still expect a RTH situation if my stock controller’s signal is; obstructed, turned off, looses power.
• Install a more robust third-party Rx onboard the craft. Again, I don’t have any experience with this either but same as above.
• Always make sure you can get eyes-on the Phantom’s lights, so you can monitor any potential compass failures and perhaps switch to ATTI to manually fly home. Altitude and distance will be fairly limited if deciding to practise this one. Or get a spotter with binoculars.
• Fly ATTI only. Very risky when flying distances / high altitudes. I wouldn't even attempt this mode unless I was flying in close range. I bought the Phantom 2 mainly for filming. The failsafe mode is the dealmaker for users like me.
• Fly FPV with iOSD / telemetry. This was going to be my next upgrade. I guess it further complicates debugging a potential flyaway as it introduces more variables, but at least you could get an idea of the flight path / erratic behaviour prior to any flyaway issue - providing you’re in range of your FPV’s signal.
• Film your flight from a tripod mounted camera / friend with a cam etc. Not always practical and not always going to explain stuff, but may help rule out certain causes and/or help others to avoid mistakes.
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In conclusion
I’d love to know what happened to my P2. I strongly suspect it’s a compass / GPS thing and it tripped out and never initiated a RTH. The cause will no doubt be an unsolved mystery. I really wonder if the flight software had something akin to a kernel panic.
With the power that comes with these cool devices, we should all be continually conscious of the risks. No doubt, safety improvements will follow in years to come. I’d hope eventually these crafts could somehow communicate realtime flight data (black box style, not just telemetry). This way you could know for sure what went wrong in the case of a mechanical / software error. This is critical to rule out human error gong forward. A built in GPS tracker would be a great feature too.
Hope some of this is useful to others. I'll add updates if I get any more info. Cheers.