Dry Air Pumps

Tempest® Dry Air Pumps

Tempest offers a complete line of new and overhauled dry air pumps.  Our pumps are FAA-PMA approved and meet the demands of today’s light aircraft.

All new and overhauled Tempest dry air pumps come with our patented WIP™ (Wear Indicator Port) that allows for internal observation of the pump’s vanes.  The WIP™ helps determine if the pump should be replaced and avoid unscheduled maintenance due to a pump exceeding its life cycle.  Our pumps also include finned stators for increased cooling and an “ultra-hard” finish on the internal wear surfaces of the stator for low friction and extended life.

Tempest new dry air pumps offer a closed coupling area and our patented “LRT” diverter.  These design features will help you detect and prevent pump contamination from external sources.

Rugged and lightweight, our 240 and 400 series dry air pumps are designed with todays high performance aircraft in mind.  These pumps use a heat-treated, stainless-steel conical pressure plate spring and torsional dampening springs to provide a harmonics-free pressure plate control and smooth temperature compensation.  Our larger pumps also use hardened stainless-steel pressure plates that are precision ground and lapped to reduce internal leakage and wear.


Dry Air Pump PDF Application Guide

Information contained in this application data is for reference only. Although great effort has been made to ensure accuracy and completeness, Aero Accessories/Tempest® assumes no responsibility for the information contained within this document. Responsibility for airworthiness of aircraft, including the installation of correctly selected approved replacement of parts lies with the aircraft owner/operator per FAR 91.163, FAR 121.363, FAR 123.45, FAR 127.131 and FAR 135.143 (a). Please refer to FAA or engine/airframe/propeller manufacturers’ parts listing for approved part numbers for each application.  Tempest brand products are manufactured by Aero Accessories, LLC.

About Tempest New Pumps

Each pump is meticulously and professionally hand assembled to insure proper tolerances and clearances. This assures optimum performance. After assembly, each pump is functionally tested. After this initial testing, the pump is then disassembled, inspected for any unusual wear or abnormalities, and reassembled for a second test run. This extensive testing procedure assures that only first-class products leave our facility.

About Tempest Overhauled Pumps

When Tempest receives a core, it is disassembled and all carbon is discarded. Tempest never re-uses carbon. We use a new stator on all 200 series pumps. Our larger 400 series pumps have the hard anodize stripped from the center stator and the stator is inspected for cracks. We then perform a reconditioning of the I.D. After the reconditioning process, each 400 series stator is meticulously inspected for proper dimensions. The stator then receives a new hard anodize coating. We inspect 100% of the parts that we re-use in the overhaul process to make sure that each part meets the requirements for our FAA-Approved process specification 203-6-1009.  

Q: Which Dry Air Pump is correct for installation on my aircraft?
A: Please refer to the application chart on the dry air pump page to find the correct pump for your aircraft. If you or your mechanic will supply us with the aircraft make, model and engine type, we will be happy to provide you with the applicable pump for your aircraft (call 1-800-822-3200 or e-mail gehrlich@aeroaccesories.com). 

Q: Is an overhauled Dry Air Pump as good as a new pump?
A: We can only speak for our own overhauled pumps as we have no control over the quality of other overhaul shops. Before Tempest®/Aero Accessories, LLC offered an overhauled pump, we spent more than a year in research and testing to determine what was required to produce a quality overhauled pump that would last as long as a new pump producing the vacuum or pressure required for aircraft application. In 1984 Tempest®/Aero Accessories, LLC had its overhaul process specification approved by the FAA and began offering quality overhauled vacuum pumps to general aviation. We take great pride in our state of the art overhaul facility, and produce the best overhauled pump on the market today. Over the years we have acquired FAA-PMA’s for all component parts of the Dry Air Pumps, and have supplied replacement parts to all overhaulers worldwide.

Q: When I start my engine the vacuum gauge reads zero vacuum, but as the engine RPM increases, the gauge will indicate vacuum. What causes this?
The carbon vanes inside the pump are sticking in rotor slots. Oil or solvent has entered the pump either from a bad oil seal in the engine case at the pump mounting area, or from pressure washing the engine with an oil-based solvent (spraying directly on the pump). The oil or solvent will work its way up into the pump through the drive end, mixing with graphite dust and turning into a paste like material.

A Dry Air Pump is just that: DRY. As the carbon rotor and vanes wear, they produce graphite dust which lubricates moving internal parts of the pump. When oil or solvent mixes with this graphite dust, it keeps vanes from moving freely in their slots and they stick. At low engine RPM, the vanes are recessed in their slots and create no vacuum, but as engine RPM increases, centrifugal force slings the vanes out, allowing them to grab air and create vacuum. Once a pump has become contaminated, its life expectancy is extremely short. The cause of pump contamination should be determined and corrected and the pump should be replaced as soon as possible. 

Q: What procedures should be taken when replacing a failed pump?

A:  (1) A correctly functioning pump creates a vacuum in the system lines, so when the pump fails (due to wear or from FOD which has entered pump) the carbon rotor and vanes break into very fine pieces which can be sucked back up into the inlet hose. It is very important to remove the inlet and outlet hoses from the aircraft and clean them out thoroughly, making sure to remove all particles. It is imperative to clean the entire system after a pump failure. By doing so you will eliminate the chance of premature failure by your new replacement pump as a result of carbon FOD from a previously failed pump entering your new system.

(2) After you have installed the new replacement pump, check and make sure the aircraft vacuum system is working properly. A faulty regulator , dirty vacuum pump filter, or a crimped or partially collapsed hose which causes a restriction in the system can force to pump to work harder, causing premature failure.

(3) If your aircraft engine has high time, go ahead and replace the oil seal in the engine case where the pump mounts. The area could be dry now, but the seal could start leaking in just a few hours causing oil contamination in your vacuum pump, making it inoperable. Less than $10 dollars spent here could save you hundreds of dollars later.

Q: I frequently need to replace my Dry Air Pump. What could be causing this?

A: 1. Check your hoses to make certain that they are not collapsed or kinked.
2. Replace the system filter(s). A dirty or clogged filter will cause the pump to work significantly harder than normal and could cause premature failure.
3. Make sure that you have the correct pump installed on your aircraft.
4. Make sure that no oil contamination is entering the pump.

Q: Should I use a cooling shroud on my dry air pump?

A: Yes, using a cooling shroud whether on a 200 series or 400 series dry air pump can reduce pump temperatures by as much as 10%.  If you are interested in purchasing a cooling shroud please contact McFarlane Aviation