You should have a look at the " aftermath " column in the last
" Flying " magazine. It discusses the fatal crash of a Australian
PA 31 after a double engine failure. Overly aggressive leaning
was implicated in the accident. Personnaly I run all turbocharged
flat engines at a maximum of 1400 - 1440 deg TIT depending on the particular engine. I know of one operator who tried to fly a
C421 with lean of peak mixture settings. He lunched 3 engines in 18 months.