Twin Decent Forecast Arcs?

[Guest JoeMathews]

Hi,I see on this picture there seem to be two decent forcast arcs on the Captain's ND. Is it just something to do with the picture (maybe a slow shutter speed because it's dark) or is it actually there? You can just see a bit of the FO's ND and I can't see the corner of a second arc. What do you think/know?http://www.airliners.net/open.file/1214064/L RegardsJoe Mathews

[lbarber 20]

Its almost surely because of the slow shutter speed. The arc probably moved because the aircraft decelerated, e.g. arc was settled at point A, decent rate slows and it settles again at point B.-Lee Barberhttp://home.nc.rr.com/uniuniunium/dvasig.jpg

[basa 0]

Well, I am not an expert photographer, but, don't you think that if it had to do with the shutter speed, then a broad green band should had appeared on the ND screen reflecting the different and multiple positions of the green arc moving during the exposure time ?Jose Luis.

[rgamurot 1]

>Well, I am not an expert photographer, but, don't you think>that if it had to do with the shutter speed, then a broad>green band should had appeared on the ND screen reflecting the>different and multiple positions of the green arc moving>during the exposure time ?I'm inclined to agree. Even if it was a quick movement, you would still see a faint band between. But why would you need two arcs? Ryan GamurotLucky to live Hawai'ihttp://www.virtualpilots.org/signatures/vpa296.png

[tunnelcat 1]

If you will look closely at the first officer's display on the right, you can barely make out a single arc and not the other one that shows up on the left display. It looks like a very long exposure was taken since there is a lot of movement blurries with the crew.I bet that these displays are LCD's and that this was an artifact that occurred when the display redrew during the exposure time. Just a guess.Kim

[VHOJT 172]

We don't know how the computer draws the arcs onto the screen - it may have done a recalculation and the arc may have simply have been "moved" without a smooth transition? But that still wouldn't explain why there was two. I am rambling.

[Guest Daniel Pimentel]

Actually, not necessarily, depending on the length of the exposure. If the movement was relatively smooth and fast (which it usually is), but settled at those two spots for a period of time, that would explain why no "band" is visible.Daniel P.http://www.precisionmanuals.com/images/forum/supporter.jpgMember of SJU Photography. [A HREF=http://www.jetphotos.net/showphotos.php?userid=9004]Click Here[/A] to view my aircraft photos at JetPhotos.Net!The official psychotic AA painter. :)

[Check_Airman 3]

That MAY be the OFFPATH DESCENT circle being displayed. PMDG has not implemented it, but it exists in the 744, where the FMC will show you a clean descent circle, and one with spoilers extended.Paul

[tunnelcat 1]

If that's true, wouldn't you see it displayed on the first officer's ND screen as well? Just enough of his display is showing that you should be able to see the second arc there.Kim