Engine Lubrication Systems
Engine Lubrication Systems is a core knowledge area on the AMT — Powerplant FAA written exam. This hub collects our 16 in-depth, ACS-aligned engine lubrication systems articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
Viscosity and Viscosity Index in Aviation Lubricants
Viscosity measures an oil's resistance to flow and is the single most important property of any aviation lubricant; viscosity index describes how well that resistance holds up across a wide temperature range.
Wet-Sump Lubrication System Operation and Components
A wet-sump lubrication system stores oil directly in the engine crankcase and circulates it under pressure to all critical components; understanding its parts and operation is essential for AMT Powerplant certification.
Dry-Sump Lubrication System Operation and Components
Dry-sump lubrication systems keep oil in a separate external tank rather than the engine crankcase, enabling consistent oil supply under high-G flight conditions and improved engine cooling — essential knowledge for AMT Powerplant certification.
Functions and Properties of Aviation Engine Lubricating Oils
Aviation engine lubricating oils perform multiple critical functions beyond simple friction reduction, with specific chemical and physical properties that make them uniquely suited to the extreme demands of aircraft powerplants.
Oil Pressure Relief Valve Function and Adjustment
The oil pressure relief valve caps maximum system oil pressure to protect engine components; understanding its function and proper adjustment is essential for AMT powerplant certification.
Engine Oil Pump Types: Gear, Gerotor, and Vane Pumps
Aircraft engine oil pumps—gear, gerotor, and vane types—move oil under pressure through the lubrication system; understanding how each works, their advantages, and failure modes is essential for AMT Powerplant certification.
Straight Mineral Oil vs. Ashless Dispersant Oil for Piston Engines
Straight mineral oil and ashless dispersant oil serve different roles in piston engine lubrication — knowing when to use each is critical for proper engine break-in, maintenance, and airworthiness.
Full-Flow vs. Bypass Oil Filtration Systems
Full-flow and bypass oil filtration systems each protect aircraft engines in different ways — understanding both is essential for AMT Powerplant certification and safe engine maintenance.
Oil Cooler Design, Operation, and Thermostatic Bypass Valves
Aircraft oil coolers remove excess heat from engine oil using air or fuel as the cooling medium, while thermostatic bypass valves regulate oil temperature by controlling how much oil flows through the cooler versus a direct bypass path.
Oil Temperature and Pressure Monitoring: Acceptable Ranges and Troubleshooting
Oil temperature and pressure are the primary indicators of engine lubrication system health; understanding their acceptable ranges and what abnormal readings signal can prevent catastrophic engine failure.
Oil System Contamination: Metal Particles, Water, and Fuel Dilution
Oil system contamination from metal particles, water, and fuel dilution can silently degrade engine protection and signal serious mechanical problems — recognizing and responding to each type is essential for safe aircraft maintenance.
Turbine Engine Lubrication System Components and Oil Types
Turbine engine lubrication systems use pressure-fed, recirculating oil circuits with specific synthetic oils to cool and protect bearings, gears, and seals under extreme conditions.
Synthetic Turbine Lubricating Oils: Properties and Specifications
Synthetic turbine oils are engineered lubricants formulated to meet precise military and commercial specifications, providing exceptional thermal stability, load-carrying capacity, and oxidation resistance in gas turbine engines.
Oil Breather and Pressurization Systems in Turbine Engines
Turbine engine oil breather and pressurization systems vent crankcase pressure, prevent seal leaks, and protect bearing compartments from oil loss — critical knowledge for any AMT powerplant technician.
Oil Consumption Analysis and Causes of Excessive Consumption
Excessive oil consumption in aircraft engines can indicate serious internal wear or seal failure; AMT powerplant technicians must systematically diagnose its causes to maintain airworthiness.
Servicing, Draining, and Flushing Aircraft Engine Oil Systems
A complete guide for AMT Powerplant students on correctly servicing, draining, and flushing aircraft engine oil systems, covering procedures, safety rules, and FAA-tested specifics.
More AMT — Powerplant subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.