MA2 (RC Disconnected) No RTH, Drone gone

[Scott]

Flying no problem, and not even that far away and suddenly I get RC Disconnect to Drone. Just beeps, no Return to Home. Gone forever.

Flight Log Attached.

 

[PhantomFandom]

Flying no problem, and not even that far away and suddenly I get RC Disconnect to Drone. Just beeps, no Return to Home. Gone forever.

Flight Log Attached.

I only took a cursory look at the log and I am by no means the master log interpreter that @sar104 is. However, it seems to me like that this was controlled flight into terrain. At 12m 2s, you were heading home with right stick full forward. Left stick was neutral so you were holding altitude at 93 ft. Seems to be little or no wind since the drone was coming back to you at 27 MPH. So all is good up to this point.

However from that point forward I see that you still applied full forward on the right stick but also added almost full down on the left stick. The drone did exactly as you told it to and started descending rapidly. Just 8 seconds later the altitude was at zero. One second after that, the flight record ends with an attitude that seems 90 degrees to the right. That is most likely when the drone had crashed and you got the RC disconnect. It could not RTH because you crashed it.

I may be wrong, but that is what I see.

 

[boblui]

The throttle stick was held all the way down near the end of the flight, altitude decreased gradually until the drone hit the water after 9 seconds.

 

[Scott]

I was at about 93ft, when I lost connection to RC. I was no where close to the ground (water). I let go of the sticks at first waiting for the drone to RTH, but that never happened, so I tried moving it around, and trying to get LOS. Just kept beeping. Been flying for 5 years, and there was nothing in the way as I was over water. I was literally watching the video and definitely wasn't even close to the water and then that is where the signal to RC was gone. At this point the single Compass is definitely a concern as it is my only thought as this point.

 

[PhantomFandom]

I was at about 93ft, when I lost connection to RC. I was no where close to the ground (water). I let go of the sticks at first waiting for the drone to RTH, but that never happened, so I tried moving it around, and trying to get LOS. Just kept beeping. Been flying for 5 years, and there was nothing in the way as I was over water.

The log shows that the controller never lost connection with the drone until the crash.

When you say that you lost connection, what exactly happened? Perhaps you lost connection between the mobile device and the controller? That is completely different than the controller losing contact with the drone, and would line up with what you are saying. The drone would not have automatically initiated RTH because it still had a full control signal.

Since the log shows control inputs on your part and corresponding actions from the drone, this may have been what happened. In such cases, the best course of action would be to let go of the sticks first and try to reconnect your mobile device to the controller. If that fails, fly the drone home manually with VLOS. However it seems that you had flown beyond VLOS so the next step would have been to manually initiate RTH from the controller. It likely would have come right back to you.

 

[svenmarbles]

You never lost connection and you landed it in the water ??‍

 

[PhantomFandom]

At this point the single Compass is definitely a concern as it is my only thought as this point.

The log shows no IMU, GPS, or compass errors of any kind. I don't think this was a hardware issue but as stated previously, pilot error.

 

[sar104]

Flying no problem, and not even that far away and suddenly I get RC Disconnect to Drone. Just beeps, no Return to Home. Gone forever.

Flight Log Attached.

I can't figure out what you were trying to do there. As @PhantomFandom and @svenmarbles point out, the aircraft didn't lose connection - you flew it into the water.

At 722 seconds, while it was heading back to the home point, you applied down throttle causing it to descend into the water:



That resulted in the following flight track:



The disconnect was when it submerged.

 

[svenmarbles]

Can you upload the cache video?

It’ll show when the connection drops..

 

[PhantomFandom]

I can't figure out what you were trying to do there.

I can only surmise a bit of disorientation and panic perhaps. Thinking that the controller had lost connection to the drone, just moving the sticks and not realizing he was flying it right into the water. Most likely his mobile device lost connection to the controller and thus he was thinking that he had no control over the drone.

 

[pelermon]

Well that did not go as expected.

 

[boblui]

I was at about 93ft, when I lost connection to RC. I was no where close to the ground (water). I let go of the sticks at first waiting for the drone to RTH, but that never happened .....

The altitude stayed at 28.5 meters or 93 ft throughout the 2nd half of the flight. I believe disconnection happened during that time period. However, the log shows that aileron and elevator input has never stopped so I cannot see any waiting for RTH. Finally full throttle down was applied to land the drone into the water.



As said by the others, it seems that the disconnection was between the RC and the phone. What's worth trying is to restart the DJI app and check the cable betwen the RC and the phone.

 

[sar104]

The altitude stayed at 28.5 meters or 93 ft throughout the 2nd half of the flight. I believe disconnection happened during that time period. However, the log shows that aileron and elevator input has never stopped so I cannot see any waiting for RTH. Finally fully throttle down was applied to land the drone into the water.



View attachment 104604

There were no signal disconnects during this flight.

 

[sar104]

I can only surmise a bit of disorientation and panic perhaps. Thinking that the controller had lost connection to the drone, just moving the sticks and not realizing he was flying it right into the water. Most likely his mobile device lost connection to the controller and thus he was thinking that he had no control over the drone.

No - the mobile device didn't lose connection to the controller - if it had then the telemetry would be missing from the log file.

 

[PhantomFandom]

No - the mobile device didn't lose connection to the controller - if it had then the telemetry would be missing from the log file.

Ah yes of course. Duh on me. Thanks!

 

[svenmarbles]

The altitude stayed at 28.5 meters or 93 ft throughout the 2nd half of the flight. I believe disconnection happened during that time period. However, the log shows that aileron and elevator input has never stopped so I cannot see any waiting for RTH. Finally fully throttle down was applied to land the drone into the water.



View attachment 104604

At no point was the connection less than 100% until it went into the water.

 

[boblui]

It seems that the RC gave a false indication on the status of the radio connection. May be the event log in the .DAT file will give more details.

 

[PhantomFandom]

No - the mobile device didn't lose connection to the controller - if it had then the telemetry would be missing from the log file.

Just trying to reconcile the log file with the pilot's account though. He said he lost connection when the drone was at 93 feet, which reconciles with when the control inputs made it dive into the water.

Just wondering if it's possible to lose FPV and on-screen telemetry but the app is still logging data it receives from the controller? Not a complete crash/freeze of the app but a partial malfunction where the pilot gets no info but logging still occurs?

 

[sar104]

It seems that the RC gave a false indication on the status of the radio connection. May be the event log in the .DAT file will give more details.

There were no disconnections, either between the aircraft and the RC or between the RC and the mobile device. What "false indication" are you referring to?

0.0 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

0.0 1.9 =AIRCRAFT IN WARNING ZONE (CLASS C AIRSPACE). FLY WITH CAUTION)​

6.9 /HOMEPOINT UPDATED. RTH ALTITUDE ADJUSTED TO 92M)​

9.9 95.6 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

96.8 IN FLIGHT​

198.5 @AIRCRAFT IN ALTITUDE ZONE (ALTITUDE LIMIT: 0M). FLY WITH CAUTION)​

198.5 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

198.5 ALTITUDE ZONE 150M​

203.9 448.4 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

450.5 IN FLIGHT​

457.4 @AIRCRAFT IN ALTITUDE ZONE (ALTITUDE LIMIT: 0M). FLY WITH CAUTION)​

457.4 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

457.4 ALTITUDE ZONE 150M​

462.9 528.6 =AIRCRAFT IN WARNING ZONE (CLASS C AIRSPACE). FLY WITH CAUTION)​

533.9 660.2 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

661.3 IN FLIGHT​

682.3 =AIRCRAFT IN WARNING ZONE (CLASS C AIRSPACE). FLY WITH CAUTION)​

687.9 721.0 @AIRCRAFT IN ALTITUDE ZONE (ALTITUDE LIMIT: 0M). FLY WITH CAUTION)​

721.0 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

721.0 ALTITUDE ZONE 150M​

725.9 731.6 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)​

731.9 +SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)XCOMPASS ERROR. ENSURE THERE ARE NO METAL OR MAGNETIC OBJECTS NEAR THE AIRCRAFT AND CALIBRATE IT BEFORE USE.(CODE: 30060)​

731.9 COMPASS CALIBRATION REQUIRED​

731.9 <COMPASS INITIALIZATION FAILED. RESTART AIRCRAFT(CODE: 30063)+SD CARD SPEED LOW. CHANGE CARD(CODE: 10028)XCOMPASS ERROR. ENSURE THERE ARE NO METAL OR MAGNETIC OBJECTS NEAR THE AIRCRAFT AND CALIBRATE IT BEFORE USE.(CODE: 30060)​

731.9 COMPASS INITIALIZATION FAILED​

 

[sar104]

Just trying to reconcile the log file with the pilot's account though. He said he lost connection when the drone was at 93 feet, which reconciles with when the control inputs made it dive into the water.

Just wondering if it's possible to lose FPV and on-screen telemetry but the app is still logging data it receives from the controller? Not a complete crash/freeze of the app but a partial malfunction where the pilot gets no info but logging still occurs?

The log doesn't record the video feed status, but the log is recording the on-screen telemetry - that's what OSD means.