Which option correctly represents the normal oil pressure range above 60% N2?

Which option correctly represents the normal oil pressure range above 60% N2?

• A. 40 to 60 PSIG
• B. 50 to 70 PSIG
• C. 60 to 83 PSIG
• D. 70 to 90 PSIG

Answer: (C)

Oil pressure in a turbine engine increases with engine speed because the oil pump must deliver more flow to the expanding load of bearings and gears as N2 rises. When the engine is operating above 60% N2, the system is designed to maintain lubrication within a specific pressure band. The normal range for that condition is 60 to 83 psi, which reflects the pump output and relief valve settings chosen to protect the engine bearings while avoiding excessive pressure that could stress seals and components. Staying in this range indicates the oil system is functioning correctly at higher speed. If the pressure drops below this band, lubrication may be insufficient; if it rises above it, there could be an issue like a restricted relief valve or other oil system abnormality that warrants maintenance.

Oil pressure in a turbine engine increases with engine speed because the oil pump must deliver more flow to the expanding load of bearings and gears as N2 rises. When the engine is operating above 60% N2, the system is designed to maintain lubrication within a specific pressure band. The normal range for that condition is 60 to 83 psi, which reflects the pump output and relief valve settings chosen to protect the engine bearings while avoiding excessive pressure that could stress seals and components. Staying in this range indicates the oil system is functioning correctly at higher speed. If the pressure drops below this band, lubrication may be insufficient; if it rises above it, there could be an issue like a restricted relief valve or other oil system abnormality that warrants maintenance.