When browsing through the February AAIB bulletins, I came across this one:
http://www.aaib.dft.gov.uk/publicati..._1__g_nobi.cfm
Apparently, the pilot left carburettor heat on during a circuit which, eventually, caused the engine to run roughly and lose power, accompanied by the release of dark smoke.
What is the mechanism that causes this to happen? In particular, why would the engine start to run roughly only half way through the circuit, and not on initial application of full power with carburettor heat on?
