Fuel Line Chafe

Good catch and reminder.

When pulling the Collins transponder for service, I found the fuel line behind the transponder had chafed against the antenna fitting.  The fuel line is an overflow return line to the port wing tank.  The line did not leak but was quite thin.  The pictures show the fuel line in position, the fitting on the transponder which was rubbing against the fuel line, and a close up of the cut tubing showing how thin the line was.  When I first saw the black dust below the chafed area, I thought it was smoke from an electrical problem.  Turns out, it was aluminum from the chafe.  The transponder was installed about 15 years ago.
I carefully looked at all the fuel lines at annual but this was hidden behind the transponder and I never thought about it being a problem.  The moral of the story is:  be mindful of critical components hidden from view.

John Earl
415-C N99891
S#2514