Vacuum pumps provide the suction needed to power in-flight instruments. They have been a part of aviation for many years and are still installed in a majority of piston-powered aircraft to this day. The vacuum pump is bolted to the back of your engine typically, which turns the pump when the engine rotates. Your vacuum pumps draws air through a filter creating negative pressure, which actuates your attitude indicator and directional gyro.
These important components do their job in the background, generally unnoticed, and frequently go underappreciated. The chances are that your airplane has at least one vacuum pump that rarely gets serviced. While high-quality vacuum pumps are typically sound, you should still check on the pumps regularly to eliminate any potentially serious problems. Many small planes have backup systems, but good maintenance is always better than relying on backup systems.
Here, we'll discuss why vacuum pumps fail, the steps you can take to avoid instrument failure, and avionics upgrade options that remove the vacuum pump all together.
Why Vacuum Systems Fail
Premature failure is usually caused by failing to follow the manufacturer's maintenance and replacement instructions. The pump's life span will be significantly reduced by air leaks, which force the pump to work harder. Dirty and clogged filters can also cause it to work harder, leading to an overworked pump.
Dry pumps are vulnerable to contamination by liquids. The graphite vanes in air pumps are meant to be completely dry during operation, and liquid contamination will rapidly degrade them. Solvents used to wash the engine compartment are another source of liquid contamination. Just a small amount of this type of substance can cause the pump vanes to become brittle and fracture.
Another common problem is a leaking pad seal gasket between the flange and accessory case. In fact, any leak that allows oil to get into the pump can cause damage. For example, oil on the vacuum regulator can soak the foam garter and be sucked into the pump itself but of course, even well-protected pumps are prone to fail, which can be even more dangerous than an overworked pump since failure may be more difficult to anticipate. If you’ve experienced premature failure, you need to do some troubleshooting to discover the cause before you install another pump.
Annual Vacuum Pump Inspections
The key to ensuring your vacuum pumps are in good working condition is to include them in your regular inspection routines. Whether you conduct annuals or 100-hour inspections, make sure to include your vacuum pumps. Check for structural, mechanical integrity, security, and cleanliness around the pump, being sure to check closely for leaks.
Verify your panel-mounted gauge readings using a calibrated instrument. Replace your air filters, inspect for deteriorated hoses, loose fittings, etc.
Upgrade to Electronic Flight Instruments
Vacuum pumps are a tried and true method of actuating your flight instruments. However, they are prone to wear, liquid or debris contamination, and failure. Instrument failure is not something you want to encounter, and vacuum pumps add an extra layer of mechanical uncertainty. Consider replacing your vacuum pump for good with an avionics upgrade to eliminate the risk.
Compact and cost-effective multi-function electronic instruments with robust battery backups such as G5's GI-275s, G3X's, and Txi's bring modern “glass cockpit” reference to thousands of aircraft that would otherwise depend on older, vacuum-driven equipment.
Before deciding upon an avionics shop, ensure you have completed thorough research with a shop that you can trust, and that offers a solid warranty like the ones offered by Sparkchasers.
Our team at Sparkchasers has more than 75 years of combined experience in the aviation industry providing avionics services, aircraft maintenance, and certifications. Our goal is to deliver the solution you need with top-quality parts and service while being friendly and easy to work with.
Get in touch with our Avionics Upgrades Team to learn more about replacing your vacuum pumps with simple, reliable, multi-function electronic instruments with battery support. Call (919) 934-1654 or email Info@FlySparkchasers.com for your free estimate.