Alta Spiraled Out of Control and Nosedive - Crashed

Discussion in 'ALTA' started by Ali Ahmed, Jan 21, 2016.

  1. Ali Ahmed

    Ali Ahmed New Member

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    Hey guys, this is the first time posting on the Freefly Forum. We purchased an Alta and Movi combination back in December (after the recall). We carefully went through this forum and the instructions that were made available to install the Movi on to the Alta along with the 14SG (for Alta) and 8FG (for Movi).

    We went on our first test flight at the end of December. After performing compass calibration we took off for the first time in manual mode and rose to about 25 feet and performed basic RC commands (left, right, forward, backward). All went well on the first take off. We landed the Alta and checked all of our settings just to be sure. We then took off again and did the same exact thing and landed.

    Finally we were ready to perform more tasks so we took off for the third time. We rose to about 25 feet once again in manual mode (the Movi was in kill mode). The Alta began to bank left and right erratically with no RC commands by the pilot. The Alta then banked right (southwest) immediately and the pilot tried to regain control however the Alta was not reacting to any RC commands and took a nosedive to the ground.

    One arm on the Alta completely snapped in half and the Movi gimbal sustained significant damage. The base of the gimbal was completely cocked and the tilt motor was not performing as it should.

    Immediately after the crash we contacted Freefly Support and left a voicemail. Adam at Freefly contacted us within the hour and took the time to listen to what happened and opened a ticket on our behalf for the Alta and Movi (Just FYI Freefly states they will not cover the Movi if it's on the Alta e.g. if the Alta crashes with the Movi and it was not due to pilot error Freefly will not cover the Movi in full). He also asked for the flight log to be emailed to him to review until the Alta and Movi arrived at their facility for investigation. A week later they informed us that the engineers reviewed the data from the Alta and it did not suggest a malfunction of hardware and the unit would not be covered under warranty. We then asked for additional data or reports and Adam provided us with the investigation report as well as a .mp4 file that showed a rendering of the flight when the Alta crashed. The report suggested that the reason for the crash was due to "pilot disorientation" or a possibility that the radio inputs were mapped incorrectly on the 14SG (wasn't possible since the two flights prior to the last flight the Alta flew fine and reacted to the RC commands properly).

    We then reached out to Freefly to assist us in understanding the report and how they concluded it was pilot error. Unfortunately there wasn't a definitive answer for the crash and they ruled that it was pilot error, thus we were left with the repair costs.

    The repair costs were $2768.55 for the Alta and $740.33 for the Movi. There was no itemization to the receipt just a lump sum amount. I had to contact them to get an idea of what exactly we were paying for. It was approximately $600 for each arm...the one arm that snapped in half and they stated that they had to replace 3 arms because there was slight damage to the hinge that holds the arm to the body. I forgot what the breakdown was for the Movi, I think it was about $200 for labor and the remaining amount was for the tilt motor and an arm.

    We were on the phone with Adam for over an hour trying to understand what went wrong with the last flight causing the Alta to crash and unfortunately there was no definitive answer. Although, Adam was extremely helpful in listening once again to how that day went, trying to see what could have gone wrong. He did give us a few pointers on what we could do when we receive the Alta and Movi. One thing he mentioned was placing another receiver on the Alta for redundancy.

    So to get to the bottom of this, I was wondering if some of you veteran Alta flyers could review the flight log, investigation report, and the .mp4 file to see what could have gone wrong. We still don't believe it was pilot error due to disorientation as the first two flights went really well. We have flown the spreading wings series in the past and decided to move up to the Alta, I wouldn't say we're expert flyers as there is always room for improvement, but we have been flying the spreading wings series and other X8 configs for the past 2 years.

    Here is the link to the .mp4 file they sent to us as well.


    Here is the dropbox link to the flight log data
    https://www.dropbox.com/sh/vpnv969slafme2u/AABfGSc9gDRbkgHKofVbTWxVa?dl=0

    Any help would be much appreciated! Thank you!

    By the way Adam at Freefly went above and beyond trying to help us out over the past couple of weeks. If you ever run into any issues try and see if you can speak with him. The Alta is great unit as we have seen it fly by one of our buddies, just afraid to fly ours again given the first hand experience we had.

    Setup:
    Freefly Alta
    Freefly Movi M5 with Aero Landing Gear Kit
    Futaba 14SG for Alta
    Futaba 8FG for Movi
    SmallHD AC7 Monitor and Amimon Connex for Video Downlink (Camera Man)
    Black Pearl and Flysight TX for Pilot FPV
    2x Freefly 10,000mAH Lipo
    Sony A7R II
     

    Attached Files:

  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ali:
    Sorry to hear of this mishap with the ALTA. (I can confirm that Adam's very knowledgeable and very helpful!).

    Thank you for posting all this information including the log files. It provides a suitable amount of evidence for the specific accident.

    I hesitate to dig into the Synapse flight log only because I know the guys at FF personally and therefore have first-hand knowledge of how competent (and thorough) they are -- so I rather doubt that I (or anyone else) will find something they have overlooked.

    But, to better understand the accident, might I ask some background questions:

    1. How were the orientation boom lights configured? (Which booms had which colors?)
    2. How many flight hours did the pilot have "on type" (that is, flying the ALTA)?
    3. How many flight hours did the pilot have with multi-rotor RC aircraft?

    I'm certainly not trying to impugn the pilot's reputation -- but it would be helpful to have that "side" of the story (I speak as someone who has never lost orientation on the copter. Well, not that often recently. Ok. Not this year. But it did happen on several occasions in my early Cinestar flying days. :rolleyes:). I suspect every multi-rotor helicopter pilot has "been there."

    Andy.
     
  3. Ali Ahmed

    Ali Ahmed New Member

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    Hi Andy,

    Thanks, it happens, but I appreciate the sincerity. Adam was extremely helpful through out the process, glad someone else can vouch for him too.

    I figured the more information I would provide the better. I know the message is kind of lengthy. Good to know you know the staff at Freefly, are you affiliated with Freefly?

    The answers to your questions are below, respectively:

    1. The front two booms were green, the rear two booms were red, and the side two booms were blue.
    2. The Pilot, my business partner, has had about an hour and a half of flight with the Alta. I would say about half hour that day and 1 full hour with our buddy that also owns a Freefly Alta.
    3. In total the Pilot has about 70 hours of flight time with the DJI S900, S1000, Gryphon, and a few other brands as this is our primary business. This does not include flight hours with the smaller rigs such as the Inspire 1, Phantom series, and 3DR mutli-rotors.

    We have had many orientation problems in the past when we first started out, definitely not going to deny that; we're not all perfect :). No offense taken with the above questions, theres always room for improvement.

    Thank you for taking the time to read the initial thread.
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    I'm quite curious about this data point: "After the test flights, the pilot and camera operator went to 2 man operation." This in combination with the apparent mismapping of the TX controls implies to me that I'd want to carefully check the bindings of the transmitters and receivers being used on the ALTA and MōVI. If there was a binding error, it's possible that the MōVI's Futaba could have been interfering with the ALTA's Futaba. It's not impossible, and is actually quite simple to do.

    Does your ALTA have one or two receivers?

    But also the OP says "the Movi was in kill mode". Now if that means that the MōVI was effectively powered off, I'd be concerned that it could be "flopping" around, and could cause an issue with the SYNAPSE possibly overcorrecting, which might in turn alarm and disorient the pilot.

    I've heard of one other ALTA crash when it's MōVI was in "kill" mode, and I wonder if that is a situation that should be avoided. The MōVI should be "locked", not "killed" when it's in the air. I've seen cases where a MōVI can flop around quite a bit.

    I hope you can learn something from this. And I know we all appreciate you sharing your information with us. That's the power of community. So sorry for your loss!

    Steve
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ali:
    Thank you for the information -- speaking as someone who also flies the Inspire 1, Phantoms, etc. it sounds like your pilot was pretty experienced.

    One of the great things about this forum, as Steve mentions, is that it's a way to to share experiences so others can learn from them.

    What's your gut feel for what happened here? The log file does suggest that the ALTA was indeed doing what was commanded.
    Do you think it might have been pilot disorientation? (That said, 70+ hours with copters would tend to suggest that is somewhat lower probability..)

    Steve's point is also an interesting one. The "free flopping MōVI" would certainly create quite a pendulum effect.

    Andy.
     
  6. Gary Haynes

    Gary Haynes Administrator
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    Looking at the video I could understand a disorientation scenario. Copter rotates counterclockwise by a bit less than one boom rotation. Still two booms to the back. Visually with a MoVI hanging in kill mode it might be that the pilot was focused on the orientation of the MoVI rather than the booms. Now the ship is off by 30 degrees to stick movement causing some confusion. Bright daylight the boom lights may have been a bit dim and the total flight duration/altitude didn't allow time for a recovery.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Also, if I'm not mistaken the ALTA boom LEDs are reversed from the Inspire 1 and Phantom. Not sure about the S900 and S1000.
    That might have been a contributing factor -- but that's pure speculation on my part.

    I prefer to use the rear LEDs green, front LEDs red so if I can see green, it's nose out, but if I see red, then watch out because of control reversal. But that's just an old habit and completely at odds with what the FAA will probably want us to do (nose and tail white, left is red, right is green). I'm just glad that the accelerator pedal is in the same relative place on every car in every country I've every driven.

    Andy.
     
  8. Ali Ahmed

    Ali Ahmed New Member

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    Steve,

    To clarify, we were always in two man operation however the third time we took the Alta off the ground (the time it crashed) we were going to switch the Movi from Kill mode to Dual to test the Movi.

    I'm pretty sure we mapped the RC's correctly since the first two flight went smooth. But we did check binding between the TX and RX.

    The Alta only has one receiver for the 14SG and the Movi has one for the 8FG.

    From what we've read you always have to take off with the Movi in Kill mode as the Alta will just continue to spin if the Movi is placed any other mode while on the ground. I believe "Kill" is the same thing as "Lock" mode, please correct me if I'm wrong.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ali: Given that "one receiver on ALTA, on on Movi" then it's unlikely in the extreme that there would be "crosstalk" between the two transmitters and receivers. Futaba (and many others) use frequency hopping and each data packet is "addressed" to specific a specific receiver. It would be total chaos if the transmitter/receiver binding wasn't "watertight."

    As you also, say, the if the channel mapping was awry, you would have noticed on earlier flights. The effects are "quite dramatic." Ask me how I know. :) (They were such a nice pair of trousers.)

    Andy.
     
  10. Ali Ahmed

    Ali Ahmed New Member

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    Andy,

    Yeah I would say we're pretty well versed with multi-rotors.

    That's exactly it, we're trying to figure out what happened and if there is something we could have done better. Still a little nervous flying the Alta and Movi right now.

    Our gut feeling: Honestly we still believe it was the Alta or possibly interference, but we always avoid flying near radio towers, cell towers, and power lines. I'm definitely not going to rule disorientation out cause that may have been the case, but given the level of experience we're still on the edge.

    The pendulum effect is definitely a valid concern. Is there a proper way to take off?

    From our experience, seeing others fly, and reading through docs we were under the impression that you always want to take off with the Movi in "Kill" mode as the Alta spins on the ground if the Movi is left in any other mode, I could be wrong.
     
  11. Ali Ahmed

    Ali Ahmed New Member

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    Gary,

    Thanks for looking at the video. After the Alta takes off from the ground the sudden left and right jerking is not our command from the RC, also the sudden movement to the right is also not our command. It's almost like the Alta was possessed, the only command we gave to it was throttling up, when it began to bank left and right after take off we let go of the sticks. Then the Alta did rotate as shown in the video and darted right and took a nosedive.
     
  12. Ali Ahmed

    Ali Ahmed New Member

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    We decided to keep the orientation of the lights the same as the Inspire, red=rear and green=front, to ensure we knew orientation.

    But the light feature on the app is amazing, something you can't do with other multi-rotors.
     
  13. Ali Ahmed

    Ali Ahmed New Member

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    Andy,

    That was our thought as well. We only use Futaba as our RC for the pilot and cameraman; no need to switch brands if your familiar with one.

    Thats why when Freefly suggested placing two receivers on the Alta for the 14SG (Pilot) we didn't think there would be any point. We aren't planning on flying the Alta far from us. Having two receivers would only give us strong communication from the 14SG to the Alta.
     
  14. Dave King

    Dave King Well-Known Member

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    Sorry to hear about your issues. That video shows a lot of instability to maintain level. Did they say there was a lot of user input that caused the instability? Doesn't the factory settings limit pitch and with extreme user inputs? Even in high winds with GPS I can't reproduce that kind of instability shown in the video.

    I am not happy to hear that Freefly won't cover a MOVI if the ALTA does indeed fail due to a legitimate malfunction if one ever occurs. I can understand the camera to a certain extent but why not a MOVI if the Alta has a legitimate failure?
     
  15. Ali Ahmed

    Ali Ahmed New Member

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    Dave,

    Appreciate the sincerity. The .mp4 file was exactly what we saw when we were flying, it was a bit scary. Unfortunately Freefly stated they have no way of checking our actual RC inputs, but I'm 100% sure it wasn't us rocking the Alta back and forth.

    I would also be interested in knowing if the factory settings limit pitch input.

    Yeah we weren't too happy about hearing that either. They did mention that if there was a hardware malfunction on the Alta which caused it to crash they would help us out with the repair cost on the Movi but it would not be covered under warranty. Unfortunately in our case nothing was covered under warranty.
     
  16. Steve Maller

    Steve Maller UAV Grief Counselor

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    I will tell you from personal experience that an orientation issue leading to a crash can happen to even an experienced operator. I had that happen and after hours and hours of analysis of the flight, I reluctantly admitted that I had caused it by my disorientation. It was a copter that I had hundreds of hours on and had built myself. There was no evidence of mechanical or electrical or electronic failure. So my conclusion was that I had experienced a visual disconnect causing me to fly the copter in a way not unlike what I saw in your video. It's frustrating, but part of the nature of unmanned operation. It's easy to lose your bearings.

    I'm obviously not concluding that this was what happened in your case. But in some ways you can count yourself fortunate that you didn't have an expensive camera package on there, and that the damage was relatively moderate compared to a total loss. And that there was no property damage on the ground.

    Again, I do appreciate your willingness to share the details of this unfortunate event. Thank you!
     
  17. Dave King

    Dave King Well-Known Member

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    Ali

    I was thinking about this a little more and if you had the movi set to kill and the gimbal was not balanced it could throw the entire CG of the copter off where medium user inputs could change the attitude of the copter rather quickly. If the pilot was disorientated and tried to do extreme corrections that and an Alta that didn't have a good CG could lead to the end result.

    But this does bring up a good question, does or can alta limit pitch attitude in the user settings? I'm hundreds of miles away from mine which is why I ask.
     
  18. Ali Ahmed

    Ali Ahmed New Member

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    Steve,

    Thanks for sharing your experience with me, much appreciated.

    You're right; we didn't have an expensive camera package on the Movi at that time (pure luck) and no one or property was damaged.
     
  19. Wolf Schiebel

    Wolf Schiebel Active Member

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    Ali, just to clarify for me, i would like to get back to the "kill" mode your Movi was in. Was it in "motor off" mode or in majestic (=park in airborne mode). In the motor kill mode the Movi can rotate freely, in park mode the axis are locked. If you had an empty Movi with motors off on your Alta, that could be the cause for the Alta movements, because an empty Movi is way out of balance. I don´t even know if it´s possible to get the Movi to get in "park" mode with no payload (=unbalanced).

    Just a thought...

    Best,

    Wolf
     
  20. Ali Ahmed

    Ali Ahmed New Member

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    Wolf,

    Thanks for the insight. I'm still confused on the best way to take off with the Alta carrying any of the Movi's. Based on the research I've done over the past couple of weeks, it looks like theres more than one proper way of taking off. Still looking to get some feedback from others and how they take off with the Alta and Movi.

    Based on what you're saying is the below information correct...

    Airborne Mode
    Majestic = Park Mode (Axis Locked)
    Kill Mode = Kill Mode (Axis Freely Rotate, Limp)

    We the Movi did have payload on it and was properly balanced. However, I believe we took off in kill mode.
     

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