1. Donnn

    Donnn New Member

    Just saw this posted on facebook.

    Anyone got an idea what is going on here?

    [​IMG]
     
  2. Gerard

    Gerard Member

    It looks like two of the engines aren't running or maybe have been throttled back to a very low power level. Perhaps this was done during a test flight.
     
  3. Mechanik

    Mechanik Member

    Agreed, test flight. The plane is “crabbing” across the sky due to uneven thrust. That’s why the contrail is skewed to one side. The contrail is more or less straight, but the plane is angled to the side. It’s kind of sliding sideways as it moves forward. Here is a YouTube link to an illustration:

    Source: https://youtu.be/dZ74KE90vOY
     
  4. tavacid

    tavacid New Member

    This is the oldest source I could find (1st April).
    https://www.instagram.com/aeroplanesinsta/p/Bvt0ZHkBOBl/
     
    • Disagree Disagree x 1
    • Informative Informative x 1
  5. Gerard

    Gerard Member

    That looks more like someone joking or trolling. I don't think this is any kind of standard operating procedure, but may perhaps be done by a test pilot.
     
    • Agree Agree x 3
  6. deirdre

    deirdre Moderator Staff Member

    That explanation makes zero sense for the plane in the photo. Maybe on a 4 seater little plane, but not a 747.
     
  7. tavacid

    tavacid New Member

    Yes, you're right. It sounds really absourd
     
  8. Mick West

    Mick West Administrator Staff Member

    It's possible it's a fake, look at the region on the right of the image under the engines.
    Metabunk 2019-05-19 11-20-28.

    It's trivially easy to fake.
    Metabunk 2019-05-19 11-29-21. Metabunk 2019-05-19 11-27-38.


    Not conclusive, but it seems like such an interesting shot would show up elsewhere in higher resolution.
     
  9. M Bornong

    M Bornong Senior Member

    With the date and explanation, I'm leaning towards an April Fool's joke.
     
    • Agree Agree x 2
  10. tavacid

    tavacid New Member

    I think the picture is fake
    [​IMG]
    [​IMG]

    And as Mick said, there is definetly something strange under the left engines
    [​IMG]
     
  11. Trailspotter

    Trailspotter Senior Member

    Orientation of the plane suggests that it was filmed from another plane, most likely from the cockpit. Were the photo true, it would definitely have caused a stir in the aviation-related social networks, yet there was none as far as I am aware.
     
  12. Gerard

    Gerard Member

    It would be interesting to see the same analyses applied to a similar image (ie. plane, blue sky, preferably with contrails) that likely isn't fake.
     
  13. Gerard

    Gerard Member

    I would think that the easiest way to fake this (assuming you can get this view of the plane with 4 contrails) would be to copy a portion of the background and use it to paint over the left engine contrails.

    From the JPEG error analysis shown above it's not clear this was done. Rather the entire background seems to show a suspicious blocky structure which would seem to suggest that the entire background might be fake.
     
  14. Mick West

    Mick West Administrator Staff Member

    Artifacts like this one around an object are common at high compression and do not mean it is fake.

    The region under the right side wing is different though.

    I suspect it has simply been saved at high compression to hide evidence of tampering.
     
  15. Mick West

    Mick West Administrator Staff Member

    That's just normal compression artifacts. The key clue is the different region under the wing on the right of the image. However, it does not extend all the way down, and is not conclusive.
     
  16. deirdre

    deirdre Moderator Staff Member

    someone could just ask on the Instagram post. Last year he posted something else chemtrailers latched onto, and in the comments he said something (major paraphrasing) along the lines of he is just messing with chemtrailers. I don't remember the specifics of the pic but I shared that with the woman spreading it (either FB or YouTube, I don't remember) and she said "thanks." Anyway, he/they will likely answer a "is this photoshopped?" question.
     
  17. Gerard

    Gerard Member

    I don't think the very coarse block structure is normal. I tried the analysis on a different image and didn't see anything like that, only fine scale graininess similar to what you see on this image in the plane and contrail areas of the photo.
     
  18. Mick West

    Mick West Administrator Staff Member

    It's perfectly normal for an image saved at high compression. Try this one:
    Boeing-747-Contrail-low-1200.
     
  19. Gerard

    Gerard Member

    OK, I guess the underlying cause of the coarse background structure in both images are variations in faint clouds which are difficult to see in the original images but are amplified by the JPEG error analysis.
     
  20. Mick West

    Mick West Administrator Staff Member

    More like the natural gradient of the low sky, and that alone is not causing the coarse background structure, it's the saving at a low JPEG setting that does that. You can see it in the original posted image, and more so with a simple contrast tweak.

    JPEG error analysis is often misleading, and I'd encourage people not to draw conclusions from it unless they really understand what is going on.
     
  21. M Bornong

    M Bornong Senior Member

    • Winner Winner x 5
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  22. Mick West

    Mick West Administrator Staff Member