CFM56 Engine failures
Does anyone have any idea about the nature of the failure spread (percentages) on these engines.
Are they mostly immediate failures as per the sim (e.g. instantaneous rundown /fire / catostropic failures etc).
OR
Are there more of the subtle failures (e.g. gradually reducing oil pressure/slow oil temperature increase/slow build up of vibration etc).
The reason I ask is that I have never had a sim where the failure has been anything other than a V1 cut.
Also our SOPs discourage monitioring of slow trends by having the engine instruments displayed (again assuming that the only failure will be an instantaneous one).
I seem to remember a Tristar report where the engineers had changed all the O rings (incorrectly) during maintenance and there was a gradual loss of oil over a long period of time.
On the 737 NG this would not "pop up" until the oil pressure decreased to 13 PSI (amber band)....similarly with oil temp and vibration indicators (4.0).
Surely there are sufficient instances of gradual failure to justify training of this in the sim and continuous display of engine instruments.