I have two jet engine questions.
1). In the first photo below of a Northwest DC-9-51 on short final, you can see a small trail of white smoke coming out of the bottom front area of the left engine.
I've never seen this before, so I'm wondering whether it's normal or not, as well as what the source of the white smoke would most likely be?
Photo © Ken Cheung
Here's a shot of an MD-81's (DC-9-81) engine. Does the Northwest DC-9 with the smoke trail have the same engines? If so, can the sourse of the smoke be seen on this engine?
Photo © Rainer Nyberg
2). In the photo below, what are the 3 copper coloured vertical tubes that are located at the front left side of the engine, on the outside of the case that's around the intake fan blades? What's their function?
Photo © Bruce Leibowitz