Rev drop in cruise
Our 912S is just over eight years old serviced and maintained on the dot by the same service organisation from new and has given perfect service throughout from new - the engine now has 1650 hours
This summer and several times since, when in the cruise the engine tone will drop and notice a 50 rpm drop with no commanded inputs - this happens with no other discernable reason while otherwise purring along nicely
This is enough to quicken the pulse somewhat ! - this corrects itself after approx 30 seconds and returns to normal and in most flights does not happen again , in some flights it may happen more than once
So far engineers have tried ;
Removing and cleaning all ignition connections
Carb Balancing
If you recognise the above and found out what was causing it or if you think you know what may be causing it please let me know