AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

What are Aircraft Oil Pressure gauges and How do they Work in Aircraft

Aircraft engines rely on their oil systems for various functions, so it is critical that operators can always control and monitor the pressure within such systems. To achieve this, oil pressure gauges offer pilots readings of the aircraft oil system in pounds per square inch (psi) and indicate whether the system is in a safe operating pressure range. Pilots should consistently monitor the dial of the pressure gauge, that of which often indicates safe pressure zones when the dial is within a green zone. If pressure exceeds or falls short of the ideal operating pressure, the dial enters a red zone. Dangers of improper pressure within an oil system can interfere with many vital functions of the engine, such as the lubrication of its moving parts, the temperature of the engine as a whole, and the ability to remove contaminants from the system. Therefore, a pilot should be aware of the pressure in aircraft oil systems at all times and understand how to operate an oil pressure gauge. This blog will explore the functions of oil pressure gauges, and the important roles they play in maintaining the engine(s), oil system, and safety, in general.

The oil system in aircraft keeps engines operating well, whether the engine uses a wet-sump or dry-sump oil system. The main difference between the two is where the oil is stored; in a wet-sump oil system, oil is stored within the engine in a sump, while in a dry-sump oil system, oil is stored in a separate tank. In both systems, oil is pumped through the engine to supply adequate pressure and lubrication, then returned to the original storage location. However, dry-sump oil systems offer the advantage of greater storage volume, meaning they are better for larger and reciprocating engines.

Regardless of where oil is stored, engine systems rely on oil at the proper pressure to cool the engine. As oil functions to lubricate moving parts and reduce friction, heat within the engine is also reduced. Additionally, oil provides a seal between cylinder walls and pistons, and absorbs unwanted heat from the cylinders. This keeps the engine functioning smoothly without overheating; however, pilots must be keenly aware of pressure levels to maintain these delicate operations. Often, the dial on the pressure gauge will enter a red zone if the operating pressure is dangerously low. This could indicate many circumstances to the pilot, such as possible engine failure caused by an exhausted oil supply, failure of the oil pump, burned-out bearings, or ruptured oil lines.

A pilot can rely on one of a few types of oil pressure gauges to monitor pressure levels. Today, electric oil pressure gauges are more popular; however, mechanical oil pressure gauges work similarly well. The difference between the two is in how the gauges monitor pressure. Electric gauges rely on a sensor within the engine and electric transmitters conducting readings to the pilot based on a diaphragm. On the hand, mechanical gauges rely on tubes connected to the engine which compare oil pressure to atmospheric pressure to provide a reading. Mechanical oil pressure gauges can rely on one Bourdon-tube or two if it is the dual-type pressure gauge. The Bourdon-tubes compare oil pressure to cabin pressure, and one tube should be connected to each engine on an aircraft. The face of the gauge offers readings from 0-300psi and indicated danger levels through operation markings.

Alpha Purchasing is a leading distributor of aircraft oil pressure gauges and other aviation parts that keep your engine running smoothly! We are your parts procurement partner for commercial and defense aircraft needs, so get started with us by filling out a Request for Quote form today. We offer custom quotes within 15 minutes on all items in our database, and our team of experts can even help locate parts that are not currently listed on our website. Owned and operated by ASAP Semiconductor, we source reliably from a list of only top manufacturers. Proudly operating with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation, alongside a No China sourcing policy, we can be trusted to handle the logistics and sourcing behind your operations!


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