McFarlane Aviation Products - 244CW-4OH SERIES

Part Number: 244CW-4OH SERIES

DRY AIR PUMP, Overhauled with WIP

Core Charge Required

A core charge of $100.00 is required and will be added to your cart as a separate line item (Part Number "244CW-4OH SERIESC"). Core charges will be refunded after manufacturer evaluation and approval of the qualified core. See product details for any restrictions.

Product Details

Tempest Dry Air Vacuum Pumps

Tempest offers a complete line of new and overhauled FAA-PMA approved dry air pumps. 


  • Monolithic construction 
  • Wear indicator port 
  • Revolutionary LRT oil drain 
  • Closed front end keeps oil from entering the pump 
  • Radius edges make installation easier 
  • Through bolts maintain constant body torque and alignment
  • Installation gaskets are included with each vacuum pump


All new and overhauled Tempest dry air pumps come with 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. They 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.


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


The 240 and 400 series dry air pumps are rugged, light-weight, and designed with today’s 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. The larger pumps also use hardened stainless-steel pressure plates that are precision ground and lapped to reduce internal leakage and wear. 


For these reasons and more, Tempest is the preferred dry air pump of aviation maintenance technicians worldwide.     


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 disassembled, inspected for any unusual wear or abnormalities, and reassembled for a second test run. This extensivetesting procedure assures that only first-class products leave the facility.


Overhauled Pumps

When Tempest receives a core, it is disassembled and all carbon is discarded. Tempest never re-uses carbon. A new stator is used on all 200 series pumps. The larger 400 series pumps have the hard anodize stripped from the center stator and the stator is inspected for cracks. Then the I.D. is reconditioned. After the reconditioning process, each 400 series stator is meticulously inspected for proper dimensions. The stator then receives a new hard anodize coating. All re-used parts are inspected in the overhaul process to make sure that each part meets the FAA-PMA approved requirements process specification 203-6-1009. 

Vacuum Pump Wrench also available. Get into those really tight spots!   

Dry Air Pump Specifications


Pump Model Construction Weight Length Diameter Port Size Max Continuous PSI at Pump
200 Series Pumps Short Finned Stator, Fixed End Plate  1.95 lbs 4 3/8" 3.50" 3/8-18 NPT 5.5 PSI
240 Series Pumps Finned Stator, Thermal Compensating Plate 2.45 lbs  4 3/8"  4.06" 3/8-18 NPT 11 PSI
400 Series Pumps Finned Stator, Thermal Compensating Plate 3.20 lbs  5 7/16" 4.06"  1/2-14 NPT 11 PSI



Eligibility Notice

Please verify that this product is eligible for your aircraft before adding it to your cart.

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OEM Part Number McFarlane Part Number Comment
242CW-4 244CW-4OH SERIES

Frequently Asked Questions

Is an overhauled Dry Air Pump as good as a new pump?
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?
What procedures should be taken when replacing a failed pump?
I frequently need to replace my Dry Air Pump. What could be causing this?
Should I use a cooling shroud on my dry air pump?

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