Vision Plus Lost

[RedBaron]

Sorry this is so long but here it goes:

Today I went out in my back yard to fly my Phantom. I live on a river and was launching out back on my dock. I have done this over 300 times. It was a beautiful day out, and I started up the Phantom just like I normally do, all according to DJI instructions. On my way out to my dock, one of the motors started, turning on one of the props, (I normally turn on the controller, range extender and Phantom while I walk out to the dock). I turned the battery off, which was the only way it would turn off. After a couple minutes I powered it back on and waited for GPS signal. I had 12 satellites. I was attempting to connect my phone to the WIFI, and while I was doing this, all four motors turned on and the Phantom started to lift off the ground. I hadn't even touched the controls yet. It lifted off and immediately darted towards the water and crashed and of course sunk. I didn't have any control while it was doing this.

A couple things I will add:

1). This drone was purchased new by myself. I let my son fly it one day and he crashed it into the river. I sent it to have it fixed, and they fixed it (DJI authorized service center in Miami Florida). I don't know what exactly they did, but it was good as new. At least for a week until this happened. I received it back from service on Saturday, October 11 and it crashed today, October 15. I flew several flights in between receiving it back and the crash today, all without incident.

2). My dock does not have a roof, so there was no interference.

3). The battery was fully charged, as well as fresh batteries in controller and charged wifi extender.


Does anyone have any idea why this would happen? Could it be something that went wrong with service? Was this just a glitch? Should I spend another $1300 on a new one?

I recently sent my Phantom into LA for repair. On the customer form it stated that they would not repair a Phantom that had been under water. They said it would not be worth trying to fix. For what it is worth, I had a similar experience with the Phantom. I had everything turned on and connected and was waiting for the satellites to come on line which seemed like forever when all of a sudden it powered up the motors by itself and went straight up about 20 feet - hovered and then landed. The only thing I can think of is that there was no action for quite a long time and it possibly went into failsafe mode. This happened at the same time as my video had flipped upside down on the tablet.

RB

 

[N017RW]

The simple switching on of a mosfet causing a BLDC motor to 'spin up' is not possible.

Without commutation there can be no rotation.

This combined with the fact that 4 motors started makes the notion of an ESC problem unlikely.

So I'm not saying you're wrong, just that it is not consistent to my understanding of BLDC and ESC operation.

 

[burlbark]

The problems begin to arise when you have voltage applied to the gate Unmodulated. This back feeds the processor, which is current limited. This relatively high voltage across a signal lead cause gate failure in the processor and can make the motors spin up. I have pretty much seen it all. I have tried replacing processors and the factory flashing I cannot emulate. Some of them can be replaced and is a case by case study.

Jeremy James

 

[slothead]

I didn't read all the posts, and someone may have mentioned this, but I think (if it is a real failure and not a time-out RTH - if there is such a thing) that it would probably be a Flight Controller or ESC failure. I think it is more likely a FC failure than an ESC failure since it was able to fly at all.