Most bleed air is taken from the compressor stages - this air is not 'burnt' as such but it is damn hot (not sure how hot exactly but I'm sure someone will tell us).
Does anyone know how this would effect the levels of TCP and its by-products? Furthermore, different engines with different oils, bleed air 'tappings' and lubrication systems could all influence the concentration of the nasty chemicals. Has any research been done along these lines?
flipster