1. Mick West

    Mick West Administrator Staff Member

    Manurewa 3 frames.

    Cool footage of a sunlit contrailing jet suddenly increasing its rate of climb in the far distance. Then continuing with less persistent contrails.

    Source: https://www.youtube.com/watch?v=oJSQez3ke-s

    Misidentified as a UFO:
    5:38 PM is 5:38 AM the same day UTC, 31 July 2017
    Last edited: Aug 6, 2017
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  2. Mick West

    Mick West Administrator Staff Member

    Likely flight is Emirates 435 from Auckland to Brisbane

    No FlightAware track, so using the FR24 one (attached), at 5:38 it was 100 miles NW of Manurewa, which looks about right for the perspective.

    Viewed from the side there's a change in climb rate (so this might actually be an increased rate of climb, rather than level then climbing as I put in my first graphic)

    Viewed end on you can see the jump looks more significant with perspective

    Ground level view.
    The track is going left to right whereas the contrail is right to left, but contrails often are blown away from the track, which can be greatly magnified by the perspective compression.

    Attached Files:

    Last edited: Aug 5, 2017
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  3. Mick West

    Mick West Administrator Staff Member

    Planefinder has data, and extracting that to KML (attached) shows a similar increased climb rate at that point. 20170805-173525-mwvf3.
    The actual altitude change only too around 10 seconds, so would actually be more abrupt in the path, but you still see it in an angled view. Here I've placed the camera on the other side, assuming the contrail is being blown east

    Attached Files:

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  4. Mick West

    Mick West Administrator Staff Member

    Last edited: Aug 5, 2017
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  5. Mick West

    Mick West Administrator Staff Member

    The Himawari-8 images for 7/31/2017 are not showing up. But here's on for the next day at the same time (14:40 JST)
    You can see the cloud tops reddening to the west. A high countrail would be higher than these, and so catch the sun even in the darker looking region.
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  6. TEEJ

    TEEJ Senior Member

  7. TWCobra

    TWCobra Senior Member

    This time of year there is a strong jetstream blowing from the west present as a semi-permanent feature over NZ and Australia.

    As the aircraft climbs into it it experiences a massive increase in headwind. The only way to control the airspeed increase is to raise the nose which causes a large albeit temporary increase in the climb rate until equilibrium is restored.

    We usually encounter these from around 25000 to 30000 feet on the climb.

    The Earth Website shows a 135kmh Jetstream at 35000 feet at the time. This is probably the cause of the increased climb rate.
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  8. Mick West

    Mick West Administrator Staff Member

    That seems pretty much exactly what happened. Around that point the plane was passing through 35,000ft.
    (The 34442ft mark is at the red arrow, which is just before the recorded XX:40 time, just after the XX:38 time listed on the video)
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