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UK Taking Off From Metal Structures

Discussion in 'Certified UAV Pilots' started by tweaker, Oct 4, 2016.

  1. tweaker

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    Guys,

    Never really had any problems before taking off from metal structures(in particular bridges) however my client wants me to take off from a large water tower- approx 30m square flat top

    The contractor (who looks after the water tower) and who my client does media for says there may be interference because of "all the metal"

    Contractor I feel does not really know what they are talking about and is just not wanting the hassle for getting me on site.

    Will the metal structure affect my sensor readings on my pre flight checklist? Anyone have experience of "metal" affecting flight characteristics?

    Do all sensor readings prior to getting on structure?

    Fore warned is fore armed and all that! Just wanting to tap into the knowledge database that is on here.

    Thanks in advance
     
  2. William Gaddy

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    It can certainly affect your magnetometer/compass calibration step. If it was me, I wouldn't do that step on top of the structure, but rather at a nearby location on the ground. I would also fly P-GPS and not P_ATTI and I definitely would not trust P-FUNC for things like Point of Interest auto-orbit.
     
  3. tweaker

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    was going to fly it atti but you reckon P-Gps?

    I agree regarding compass dance but all other sensors should be normal?

    Was going to do pre flight sensor check-close down-drive onto site-then launch after obviously doing pre flight sensor check. If sensor check on site is off obviously its the high metal content and should still be good to go as I had checked it previously.......

    Hmmm-the theory side and logical elimination always hurts my head!!
     
  4. William Gaddy

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    My notion of using p-GPS is to "use all the tools in your arsenal" for a safe flight. If the DJI stops station-keeping properly you can always flip a switch to go to p-ATTI and take positive control. p-GPS (or any flights whatsoever) might not be so wise if there are co-located microwave antennae or 3G or 4G cellular antennae on the structure... also, speaking of that, if there IS a microwave repeater on this structure you might want to steer clear of it from a personal bodily integrity standpoint. Some of these things can fry you pretty well if you stand right in front of the beam path. I've heard of guys tossing eggs in front of an active AWACS forward radar for snickers and giggles and having the eggs explode mid-air, for example...
     
    Brendan Roche likes this.
  5. tweaker

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    No antenna or anything like that on the structure.

    Just the evil "metal"

    Thanks interesting ponder for me to mull over.

    Where there is a will there is a way.....
     
  6. The Editor

    The Editor Moderator
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    GPS and IMU (Gyroscopes and accellerometers) will not be affected at all. Compass most definitely will.
    Dont whatever you do attempt a compass calibration on the tower - stick with the compass calibration you have from a few weeks/months ago etc and you will be fine.

    However, (there's always a however), the structure may alter the magnetic flux so much that the Inspire throws up an error since the mod values will be outside acceptable thresholds. If that is the case, switch to P-Atti and take off that way - once you are clear of the structure you can return to P-GPS
     
  7. tweaker

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    Pretty much confirming how I was thinking how I am going to fly it.

    Always willing to listen to others ideas.

    Thanks
     
  8. huppe

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    Wonder why people still mention the compass dance.I can't remember my last dance and I've been over a lot of Europe last months.
     
  9. The Editor

    The Editor Moderator
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    Same here - cant even remember the last time I calibrated the compass on either of my Inspires!
     
  10. AeroMirage

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    I don't calibrate compass unless I travel more than 100 miles away. I turn my bird on inside my car to get it into landing mode to install camera. RC always says compass calibration required. (Since I am inside a metal structure.) I then shut it down to install camera and restart it outside on the ground away from car. It no longer says calibration is required, so I don't do it. Haven't had any problems in 500+ flights.
     
  11. MrDrone

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    I was taking off from 3-story carpark this weekend for an advertising job and had to take off on Atti and set back to P-GPS once I cleared the metal lamposts (15metres). No big issues apart from side winds when landing :eek:
     
  12. Bryan Cherry

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    I did an inspection job from a barge and had a hard time with the compass. The aircraft would not hold its position and drifted constantly. I took it up onto the shore and did a compass calibration but as soon as I got back to the barge, more compass error messages. After numerous attempts I got a good calibration and flew but the drift persisted. Once away from the barge the problems disappeared.
     
  13. Steve@AerialImagesPro

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    I have done building construction and when getting too close to the iron frame, my inspire would always start drifting around. I stopped doing that because if there were an issue and RTH were triggered I'm sure the Inspire wouldn't know which direction to fly.
     
  14. DamesNY

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    hey bud,
    I fly legally in NYC on construction sites (downtown manhattan, class G airspace) all the time.
    The exposed rebar often gives compass errors and won't let me take off even in atti sometimes.
    The solution I've found is calibrate in the air and hand launch with an assistant or bring a table or a couple of wood boxes or whatever it takes to get the craft 3-4 feet off the ground.

    once I'm 20ft up all is right in the world again.

    if you have any questions, shoot me a text or give me a call. Id be happy to offer you some tips in the weird situations we've had to solve at times. 1 917 66 Nine 333 Nine
    Demian
     
  15. tweaker

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    Guys

    Been away for a bit.

    Thank you for all the help as I was in planning phase of a particular job. I like throwing others thoughts(sensible ones!) into the mix before a try out what "should" work.

    Gig went as I planned no problems.

    Footnote I never do compass dance if my sensors are true.

    Fly safe
     
  16. Theblacksmith

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    Hi guys. One of my collleagues was filming in a harbour, and did his compass dance over a smooth slab of concrete, which was unfortunately full of reinforcing steel bars.

    During filming he had an 'incident' (unspecified) and hit the RTH button, whereby his Inspire landed slowly gracefully, but in the middle of Montrose harbour!!
    Never do your pre-flights anywhere near any steelwork!
     
    tweaker likes this.