Alta 6 crash

Discussion in 'ALTA' started by Robbert van Weelderen, May 28, 2016.

  1. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    Ok here we go.

    Today I had my first dual operator shoot with the Alta 6 ordered on 15 March 2016 from a dealer in Germany.
    The payload was a Movi M5 in ground view with a Sony FS5 and the 24mm F1,8 Sony E-mount prime, Connex HD air-unit and a S3 Lipo to power the Connex unit. A wedge unit was attached but not working used because I don't have a focus motor yet.

    The Movi was being controlled by a second operator from the Movi Controller which was working fantastic. I had 2 great +/- 10 minute runs using GenAce 6200mAH 25C battery's which according to another thread here on the forum are on the limit but from my earlier test runs and today was working great. There was not a lot of wind today and I was flying with low speeds and careful.
    Then on the third run after installing two Tattu 10000mAH 25C battery's I went up and after about 5 minutes or so (I'm guessing still have to look up timetable) me and my operator decided we got all the material we needed. We were shooting a BTS of a Horse and Hunk photoshoot and the photoshoot was also completed. I was flying to the home station carefully in GPS mode. Then at around 10 meters from me and I guess about 2 meters from the ground all motors suddenly stopped and the Alta came down.

    Luckily for me we were shooting at a sort of beach location which meant the Alta came down in sand and luckily I had it in ground view which meant that the aerial gear got most of the beating. One of the legs was almost completely broken off after it came down and during transport back to the car it fully broke. At first the Movi seemed to have a problem with roll but one of the screws was very loose and blocked full roll movement. I still have to test if the Movi works but my guess is that it will. The camera and lens survived it all without a scratch.

    After coming down the Alta went sideways in the sand and the metal on one of the arms at the folding point is bend and one of the rotors has a crack. I will post some photo's tomorrow.

    I'm a really in the dark about what happened here. I will contact FreeFly asap (first need to get some sleep) with the logger data and my story. Anybody has any idea about what could have happened?

    (Uploading the cvs file I get a too large file message, so I uploaded it to my website):
    http://www.polaire-pro.com/SYNLog-12-48-45_28-05-2016.csv
     
  2. Humberto Barchini

    Joined:
    Oct 31, 2012
    Messages:
    94
    Likes Received:
    26
    Hi Robbert... as far I can see in the logs... when the battery was near 21.0 Volts everything shut down... before that all was fine...

    Are you using the original wiring and connectors?
    really interesting to solve this...

    Very sorry for your equipment...

    HB

     
  3. Andrew Griffiths

    Joined:
    Jul 7, 2013
    Messages:
    61
    Likes Received:
    9
    Sorry to hear of this mate. I watched something very similar take place a week or so ago, but in this case the Alta 6 hit concrete. The Alta did not give a warning that the batteries were low and the programmed fail safes did nothing. Doesn't exactly fill me with confidence.
     
  4. alex ryan

    alex ryan Member

    Joined:
    May 8, 2015
    Messages:
    227
    Likes Received:
    16
    Geez. Sorry to hear about that. Really like to know how it happened. Just lucky you were only a couple of meters off the ground.
     
  5. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    Ok, a bit more info:
    I have two sets of Tattu 10000mAH C25 battery's. Two are older and used on I guess about 25 flights. The ones I was flying with yesterday when the accident happened were new (received them a week ago) and used on 2 flights.

    The last time I looked at the voltage being reported by my Fatuba controller the voltage was fine and I was nowhere near the flight times I was getting with these battery's. The Tattu's were charged a night before the accident at 1C.

    All the connectors and wiring are original, both on the Alta and the battery's. What I have always found a bit strange since I got the Alta is that the connector on the battery doesn't fully go into the connector of the Alta (and I didn't want to over force it). See one of the attached photo's on how it looks. On the connector of the charger this isn't a problem and the connectors go fully in. Since it came this way from the factory I thought it was the way it's supposed to be but now with the accident I'm doubting.

    Photo's attached:
    - Bend metal on one of the arms on the Alta.
    - Tattu packs values on the charger after the accident.
    - EC5 connectors of the Alta and battery's.

    IMG_1191.JPG IMG_1192.JPG IMG_1193.JPG
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    So sorry this happened!
    That EC5 connector should not look like that. They should always seat firmly and completely. What happens often with these things is that the spark that occurs when you connect the first LiPo causes a very small bit of carbon on the connector. When that builds up, it can cause what you're seeing. Of course, the carbon is somewhat conductive, but if the connector's not seated properly, it could cause a disconnection. I'm no engineer, but I wonder if an intermittent connection could be the cause of your crash. The ALTA's failsafe logic can't guard against a catastrophic power loss, which appears to be what might have caused this.
    Hope you get this sorted. Really appreciate you sharing this with everybody.
     
  7. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    The thing is that the connector was like this from the start of buying the machine. Because I read that Alta's are tested individually before shipping I thought it would be ok to operate.
     
  8. Howard Dapp

    Howard Dapp Active Member

    Joined:
    Aug 18, 2012
    Messages:
    977
    Likes Received:
    111
    20160529_101815-1.jpg Robbert, can you take a photo of the EC5 connector like the one I've attached at a similar angle showing the recessed copper connectors inside the plastic housing and another looking down into the connector.

    @Andrew Griffiths has the cause of your crash been investigated?
     
    #8 Howard Dapp, May 29, 2016
    Last edited: May 29, 2016
  9. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    Ok, first the connectors of the Alta from different angles.
     

    Attached Files:

  10. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    And now the connectors of the Tattu's that were on the Alta when it crashed. Do note that one because of the impact of the crash one battery was in the sand and the other was still on the Alta but not under the strap anymore. Battery's were 1 week and 2 flights old.
     

    Attached Files:

  11. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    Is it possible that something shorted the battery connector? That's a pretty severe burn on the edge of the connector. alta-ec5---7.jpg
     
  12. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    I really don't know what would have caused this. Battery has only been on the Alta after charging.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,344
    Likes Received:
    1,158
    Sorry to come to this discussion late. Humberto, if there is a total power loss, not all of the log file might get flushed out to the microSD card. Row 7369 of the .csv file is partial (terminating with column ED) which suggests we don't have all of the information.

    You are correct, though -- the LiPo voltage in the last row is shown as 21.53 volts, at 71.53 Amps.

    As Steve has commented, the EC5 connector in the first image does not appear to have been fully inserted. I am specifically NOT saying that is the cause, but merely observing that. Can you verify whether or not you can actually push the LiPo connector further into the ALTA connector or is there a "hard stop" that prevents you from doing that?

    Robert: if you have not already done so, open up a support ticket by emailing support@freeflysystems.com.

    Also preserve the microSD card untouched if you can. There may be some additional data rows on the micro SD that either FF or I can recover using forensic techniques.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  14. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    Hi Andy,

    Once more I will confirm that the LiPo connector will not go further in the Alta connector. A hard stop is preventing that. This is the case for both connectors and has been the case from the moment I got the Alta delivered.

    A ticked has been opened and I e-mailed my dealer. The microSD card has been preserved and will not be touched further.
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,344
    Likes Received:
    1,158
    Steve: That right-hand connection looks very suspect, doesn' it?

    If you look on the far left side of the right-hand connector, it's melted into the plastic. The the obvious arcing and melting of the housing on the right hand side is the worst I've seen. Looks like it was arcing for more than just the normal plug-in time -- but that said, not very long in human terms as LiPo's are effective arc-welders.

    But even speculating for a moment that the connector came apart in flight -- it might have caused the arcing and connector melting, but why would it bring down the ALTA? Could it cause a surge of some kind that browned-out the Synapse flight controller?

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  16. Humberto Barchini

    Joined:
    Oct 31, 2012
    Messages:
    94
    Likes Received:
    26
    I have those same problems a long time ago with mi EC5 connectors on a S800 EVO... the thing is... when you don´t have good connection between connector (sorry for the redundancy) then its get very hot to the point it can melt the soldering... as Andy said... it is probably a very hot connector that end with and arc that shut down the synapse...
    With my S800 I ended up my flight and when I tried to disconnect the EC5 I ended up with it in my hand unsoldered... 1 more minute flying and it had a catastrophic end!
    P.S.: sorry about my bad English ;)
     
    Steve Maller likes this.
  17. Howard Dapp

    Howard Dapp Active Member

    Joined:
    Aug 18, 2012
    Messages:
    977
    Likes Received:
    111
    @Robert your Alta to EC5 connectors look OK. I know you feel you might have mated the Alta > battery connection as tight as possible but my past 4 year experience with EC5 connectors sometimes you need just a little more pressure making the connection with "certain" devices than others.
     
  18. Robbert van Weelderen

    Joined:
    Mar 15, 2016
    Messages:
    74
    Likes Received:
    6
    @howard, sure I understand that not all connectors are the same. I have a kind of technical background in laboratory equipment. But even with using a lot of force I coudn't get the connection any thighter than on the picture.
     
  19. Andrew Griffiths

    Joined:
    Jul 7, 2013
    Messages:
    61
    Likes Received:
    9
    That connector does look suspect.

    The crash that I witnessed was not my Alta but I believe it has been sent back to Freefly and is currently being investigated. Dual 10,000 batteries onboard and none of the programmed failsafes kicked in.
     
  20. Ozkan Erden

    Ozkan Erden Distributor

    Joined:
    Aug 3, 2012
    Messages:
    678
    Likes Received:
    131
    How come both of the connectors gone bad exactly at the same time and caused total power loss?
     

Share This Page