Yesterday (April 7), on my flight to Houston (CO 51), due to the unexpected snow in the New York area, we had to do a deicing. One thing I noticed during the deicing was it appeared that when the fluid was sprayed onto a plane (both the wing of mine, and some of the others in the immediate area), it appeared to change to a dark pink / red upon contact with the fuselage / wing. From what I could tell this occured near areas where ice or snow were present.
So, for my question: Does deicing fluid actually change color to indicate the presence of ice, or was this just some sort of optical illusion, or unrelated side effect?
Also, Newark has an open air hanger that was originally built to deice aircraft, but it doesn't appear that it is ever in use when deicing is necessary. Does anyone know if it is ever used, or why it is no longer used?
Thanks in advance for any information.