As you can see, the B737-6 in these 2 shots has a very prominent dark stain on it's belly that's obviously starting from the nosegear wheel well area.
My question is ..... What's causing this stain?
I suspect it's caused by either a hydraulic fluid leak (for the nosegear steering, etc), or maybe it's from rubber flying up off the nosegear tires apon landing.
Photo © Tim Jansson
Photo © Zege - FAP
When this same 737 was clean ....
Photo © Jason Taperell - AirTeamImages
There are many photos in the database that show airliners with dark stains trailing back from the nosegear, and they all seem to be aircraft that are low to the ground on their short gear struts. That's why I thought of burning rubber flying off the nose wheel tires and hitting the fuselage as a possible cause.
Photo © Andreas Stoeckl