Does anybody know what those white dried-up drops are? I checked out another Boeing 737-800 on the ramp and it also had the same defect so I'm guessing this is a common issue, or is it? This shows up the outboard side of the exhaust by the way.
6$\begingroup$ Ehm - a seagull finding shelter? $\endgroup$– KoyovisDec 28, 2021 at 3:51
Just a guess, but it looks like deicing fluid that dripped onto the hot exhaust cone just after the engine was shut down. The origin of the drops suggests something running off the pylon side panels directly above, and the vertical tracks show that the engine was off, but the cone was still hot enough to bake off the fluid, leaving the runs of glycol residue.
$\begingroup$ Do you think deicing fluid could remain on the aircraft throughout a normal flight and then drip off after landing? Just curious. Sounds as good a guess as any, but-- ? $\endgroup$ Jan 7, 2022 at 13:28
$\begingroup$ I would think it would have all burned off if it had completed a flight after that. It looks more like something dripped and then it was just parked like that. Deicing fluid is about the only thing I can think of that would leave that sort of residue. $\endgroup$– John KJan 7, 2022 at 14:38