|Quoting eugegall (Reply 6):|
I'm 99% sure its ice and not shadow or condensation.
|Quoting zeke (Reply 5):|
The lighter area is just sunlight, the fuselage is blocking the sun, the round shadow is on the wing.
|Quoting zeke (Reply 17):|
What you are seeing is the shadow of the front of the fuselage with the sun relatively low and to the right of the aircraft. The give away is how well the light reaches the fan and under side of the pylon of #1. If the sun was higher, the rear of teh inlet and the pylon of #1 would have a shadow.
Not ice, just some sunshine. Pretty clear air there at cruise altitude, typical for the mid-Atlantic. Not a lot of moisture there.
|Quoting tdscanuck (Reply 25):|
Although I agree it's most likely a lighting effect in this particular case, it's not inconceivable to have ice only in that particular location...for many nacelle anti-ice systems, the piccolo tubes that distribute hot air inside the nacelle leading edge are shaped like a "C" with the opening pointed down (air comes in at the top in the "middle" of the C and exits small holes all along the C). As a result, if you had a marginal/failing anti-ice valve that wasn't providing full flow, the first part of the nacelle that would get cold and start to ice (assuming icing conditions were present) is the bottom center.
Not on any of our engine inlets. On all of our GE
, Pratts and Rolls engines, the anti-ice spray tube is a "O" shaped tube. No "C" shape, and the tube is a complete circle. The hot air enters from the left side of the nacelle or looking at the fan face, at about the 2 - 3 o'clock position, and exits through a tap off the spray tube that blows overboard at or very near the bottom of the inlet.
Looking at your photos provided, the engine anti ice would have been selected off with that clear air at altitude, and any build up of ice on just that one engine inlet would have been much more uniform around the entire inlet, not just at that bottom area. The number 1 outboard engine would have had some ice build up as well. Just some sunshine and shadows making a optical illusion.