How Do Vacuum Pumps Work in Airplanes

Though modern aircraft are equipped with high quality glass cockpits, a majority of airplanes still rely on traditional round-dial panels with gyroscopes operated by vacuum pumps. Also called pressure pumps, vacuum pumps are available in a variety of designs and they are all utilized to power vital gyroscopic instruments and accessories.

In most cases, operators only pay attention to the vacuum pump in aircraft when it fails. However, unless the airplane has a low vacuum indicator light on the instrument panel, a malfunctioning pump may go unnoticed, resulting in disastrous consequences. In the 80s, a series of loss-of-control accidents attributed to the failure of vacuum pumps encouraged operators to better understand these instruments. With the goal of improving their reliability and efficiency, great efforts have advanced these useful devices.

Prior to being invented in the 30s, gyroscopes were powered by suction from a venturi connected to one end of the fuselage. With this system, the gyroscope did not begin running up until just before an aircraft’s takeoff roll, making low-altitude ascent and descent quite difficult. Luckily, a vacuum pump remedies this issue by offering more suction power.

The first vacuum pumps were of the wet variety, meaning that the interface between the pump’s stator and the carbon vanes are lubricated with oil. Wet pumps proved durable, lasting through an engine's TBO. Unfortunately, they are costly and dump excess oil overboard which leaves a mark on the aircraft belly. As such, aircraft operators had to invest in additional equipment to reduce the amount of oil discarded by these pumps.

Three decades later, dry pumps made a debut in the aviation realm. They quickly replaced their counterparts as they were lighter and cheaper to produce. Their graphite vanes offered increased lubrication by gradually erasing themselves and leaving a thin layer of dust between the stator and vanes. Despite this, dry pumps have some downsides. As the vanes are held against the stator by inertia, this eventually wears down the vanes until they are too thin to remain in place. 

Vacuum pumps find use in many piston-powered aircraft, providing ample energy for the functioning of flight instruments, such as directional gyros and altitude indicators. Newer planes with glass panels may utilize a vacuum pump as a power source for backup instruments. With this in mind, they rarely get serviced or replaced when they become faulty. To avoid operating aircraft with a malfunctioning vacuum pump, finding a reputable distributor of replacement pumps is paramount.

Aerospace Buying is a premier distributor of aircraft vacuum system components and other related items, all of which have been sourced from top global manufacturers that we trust. With over 2 billion products in our inventory, customers can fulfill their operational needs with ease. Initiate the procurement process today and see how Aerospace Buying can serve as your strategic sourcing partner!

  1. Posted on April 6, 2022
  2. aviation

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