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  • @Bill,



    Lost C2 Link –C2 Link is available and the pilot is able to actively manage the flight •Lost C2 Link State –C2 Link is unavailable and the pilot is “unable to intervene in the management of the flight” –But the aircraft is performing a flight plan that was pre-programmed by the pilot following TBD ICAO procedures so is safe •Recommend states harmonize the Lost C2 Link procedures for pilots and ATC •Continue flight plan, climb to regain C2 Link, or land at alternate aerodromes? •Lost C2 Link Decision State –C2 Link is unavailable but RPS has not yet declared a Lost C2 Link •Short decision time causes “nuisance” Lost C2 Link declarations •Long decision time could lead to an unsafe condition 15 •Decision times depend on Class of RPA and operating region "

  • Moderator

    Radio issues are why the World Radio Council are working on protected spectrum for RPA C2. I don't think those systems record what they did do they?? I know nothing of DJI.

  • Developer

    the most likely reason is a strong and unforeseen interference on the operating frequency, leading to limited operability.

    It seems 'loss signs due to interference" is to the drone world as "it appeared from nowhere" in car crash world! Blame it on the unseen 'radio waves' This should be last acceptable explanation, not the first excuse!

    The pilot was able to down the aircraft and send a termination, so had connectivity. The WooKong's fails safe on connection loss is to hover (link) The way that the drone crashed seems more like the details in this post (Anatomy of a DJI- flyaway) Why would an attempt to command Return Home not have been instructed first (I bet it was, this was flight system failure for sure)

    ArduCopter lands on GPS loss and signal loss, return to home otherwise, not plummet to the earth like a stone.

  • Hi Rob,

    Obviously, for this kind of legitimate use, our UAS and UAS capabilities are still too primitive to assure "safe" operations.

    On the other hand, noting the snow on the ground and the comments above, I can also presume that a sufficiently low temperature  was present to pretty much guarantee reduced battery performance as well as the fact it was clearly in a mountain region and presumably at a moderately high elevation.

    This is one situation where private pilots do have an edge as the effects of pressure altitude are drummed into them (although a substantial number of them do crash each year at Tahoe and other high airports taking off with too much weight for their altitude).

    And of course at a competitive event like this there are all kinds of radio communications going on which could easily interfere with the rather delicate and often multiple communications systems we depend on.

    And, of course, there are a whole lot of completely unrelated things that can go wrong, our copters are no way held to the kind of requirements for reliability expected and required of manned aircraft.

    This is going to be long and not easy in solving but I do expect the auto crash system is not the answer.

    Maybe if you included a half pound of C4 you could just detonate it at altitude like our missile systems producing small enough shards to guarantee no one got hurt, now there's a solution - - right up there with importing rabbits and cane toads to Australia.


  • Moderator

    Flight termination is dangerously silly, it's like deliberately crashing your car rather than stopping or swerving.

  • @Rob,

    hard answers to easy questions

    from the official report by 

    Infront Sports


    strong and unforeseen interference on the operating frequency, leading to limited operability"

    If you read now WooKong-M Waypopint Precautions (see above in this thread)

    section 1

    this drone was not fit to be flown as camera drone at that place and time

    due to temperature limits


    Operating Temperature -5°C to +60°C


    and other weather conditions, parameters, as reported by weather report

    more details from the report follow


    The initial technical report indicates a malfunction of the drone. According to the drone operating company, the most likely reason is a strong and unforeseen interference on the operating frequency, leading to limited operability. Detecting this, the pilot followed the official security procedure, purposely flying the drone as close as possible to the ground before releasing it. The aim was to destroy the drone, in order to prevent it from losing control."

  • Darius, I'm not sure what you're saying.  What is a haendler?  What is the point of attaching the DJI instructions?

  • @Rob,

    Flight Termination System feature is ok and should be mandated by FAA.

    What you mean are haendlers.

    There is no need to drop it immediately if it starts to fly away.

    You can select Flight Termination System haendler on your own.



    The WooKong-M Waypoint takes the capabilities to a new level. Pilots can pre-program a flight including up to 50 unique waypoints with custom parameters for speed, altitude, type of turn between waypoints, and even custom robotic servo actions to be completed at each waypoint. The craft will automatically take off, complete the entire mission (including any servo actions), return home, and finally land itself right back where it took off! Rest assured there are many fail-safes in the software to account for human errors like too long of flight duration or an altitude below ground level. You also have the ability to change any and all flight parameters on the fly, during the actual flight. This is truly the most advanced multi-rotor flight control system available!



    Operating Temperature -5°C to +60°C




    1. The ability of penetrating of radio signal from 2.4GHz wireless data-link is weak; please make sure the antenna of it is always visible to the ground end during the flight. Human body, trees, buildings or hills will stop the communication between air end and ground end.

    2. You’d better put the ground end at high place. This can guarantee a good communication range.

    3. Make sure the antenna head of air end is erect down, and the antenna head of ground end is erect up. Make sure there is no obstacle between antennas; otherwise the communication range will be reduced.

    4. Ground end Link-Alarm red light on is distance alarm, red light off is safe. When it is on, you’d better return your aircraft.

    5. When ground end Link-Alarm green light is off, this indicates the communication between ground end and air end is off, whatever the state of red light.

    6. Make sure the driver is installed correctly.

    7. Please choose the right com port.

    8. Check out the power supply of wireless data-links before use.

    9. Please close the DJI assistant software before open the ground station. Otherwise there will be port conflict.

    10. Make sure the distance between 2.4GHz ground end and air end is over 1.5m; the distance between 900MHz ground end and air end is over 5m.

    11. Use the right cable for connection.

    12. High voltage servos & FBL systems can drain the flight battery fast. Please make sure your flight pack is sufficient for the flight time intended.

    13. Autopilot Mode (auto mode) means: GPS Atti. or GPS Cruise Mode in ACE;


  • John, Marco and Roberto have been speaking with the pilot.  It was a DJI Wookong-M (you know where this is going...)

    Apparently the copter started flying off, and did not respond to radio controls.  He elected to employ the independent flight termination system that is mandated under Italian regulations, which is why it crashed so heavily.  So he very well might have been within the safety corridor before the flyaway started, but then a couple seconds of flyaway while the pilot realized he had no control, then making the decision to terminate flight, might be what brought it over the racing line.  Then the momentum from the flyaway would carry it further even after the motors stopped.

    I've been very much against "flight termination systems", and this is a perfect example of why.  This is not safety!  It's flying, and you drop it.  The whole idea is predicated on the idea that you're flying in a safe area, and it suddenly starts flying away, and you drop it before it leaves the safety zone.  But what about when the safety zone is only 200 feet wide?

    How about instead of mandating these auto-crash system, they instead look at DJI's systems and, to quote The Donald, "figure out what the hell is going on over there!"

  • I don't know what it is with quads and alike but they seem to out of the blue just fall out of the sky... and with regularity.

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