I flew an AB206A in 1968, great when it was going, which was most of the time. On one otherwise normal work day, cruising at 700', (low cloud base), 4 pax plus self when a loud bang from the engine was heard and the engine stopped, we then carried out a forced landing.. The problem was that the third stage compressor bleed didn't 'seat' quite properly when closed, but only on rare occasions and at certain RPM etc., a harmonic built up which turned the compressor blades to glass and they shattered, taking themselves and the stators straight out of the exhaust.. The 'fix' was in the pipeline and fitted to later models, is that the 'C18' that I see referred to in this tread? Or did the fix come after C18. Just curious!