C20B overhaul, life limited parts requirements:
Compressor:
3500 hour overhaul.
Impeller life: 3550 hours, 9150 cycles.
Gearbox: On condition.
Turbine:
1750 mid term inspection (HMI)
#1 and #2 Turbine wheel life: 1775 hours, 3000 cycles
3500 hour overhaul
#3 and #4 wheel life: 4550 hours, 6000 cycles
Fuel control overhaul: 2500 hours
Governor overhaul: 2000 hours
Fuel nozzle overhaul: 2500 hours
Bleed valve overhaul: 1500 hours.
Fuel pump overhaul: 2500 hours.
RR 300 overhaul, life limited parts requirements:
Engine: 2000 hour overhaul (includes accessories).
Compressor:
Impeller: 10,000 hours, 15,000 cycles.
Turbine:
#1 and #2 Wheel life: 2000 hours, 3000 cycles
#3 and #4 wheel life: 4000 hours, 6000 cycles.