Williams FJ-44 series engines
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Williams FJ-44 series engines
Can someone advise how the engine cycles are determined?
Would appreciate useful advice and any leads to documents etc
Many Thanks
- Does one landing equate to one engine cycle?
- Does 6 landings during circuit training equal 6 engine cycles?
Would appreciate useful advice and any leads to documents etc
Many Thanks
I Never heard of a unique way of counting cycles for Williams so my comments are only general in nature
Cycle counts for most engine relate to fatigue life limitations of the parts under certification rules. They are hugely statistical in nature with typically margins as high as 100%.
The idea is to run a bunch of tests and in-service sampling to show that detectable cracks do not exist within the samples.
This transfers over to reviewing the operation in-service by counting only the landing cycles while assuming that 95% of your fleet never exceeds the rated life and that 100% of the fleet never exceeds an overage of a few percent.
If any part is found with detectable cracks the process needs review and adjustment of life for the whole fleet.
Cycle counts for most engine relate to fatigue life limitations of the parts under certification rules. They are hugely statistical in nature with typically margins as high as 100%.
The idea is to run a bunch of tests and in-service sampling to show that detectable cracks do not exist within the samples.
This transfers over to reviewing the operation in-service by counting only the landing cycles while assuming that 95% of your fleet never exceeds the rated life and that 100% of the fleet never exceeds an overage of a few percent.
If any part is found with detectable cracks the process needs review and adjustment of life for the whole fleet.
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Williams Engine Cycles
According to the manual, you can have full cycles and half cycles.
A full cycle contains a start, takeoff power, and shutdown, regardless of duration of the rest (idle, cruise, whatever).
A half cycle is a touch and go, a stop and go, or a ground maintenance run to max continuous (but not takeoff power).
Very useful for CJ operators, a start to ground idle power, run the air conditioning, load the FMS database, etc, then shut down is not a cycle at all; it only counts if you go to high power.
A training sortie that included 6 touch and goes, and one full stop landing, was 4 cycles.
A full cycle contains a start, takeoff power, and shutdown, regardless of duration of the rest (idle, cruise, whatever).
A half cycle is a touch and go, a stop and go, or a ground maintenance run to max continuous (but not takeoff power).
Very useful for CJ operators, a start to ground idle power, run the air conditioning, load the FMS database, etc, then shut down is not a cycle at all; it only counts if you go to high power.
A training sortie that included 6 touch and goes, and one full stop landing, was 4 cycles.
