McCauley B-20251, Relief Valve Cylinder - Tempest PMA
Tempest AGB-20251-PMA
The Tempest AGB-20251 (McCauley OEM B-20251) is an FAA-PMA replacement relief valve cylinder for McCauley applications.
- Supports stable oil pressure control by providing the correct relief valve cylinder geometry and surface finish for smooth piston travel.
- Helps prevent pressure instability caused by scoring, corrosion, or wear in the original cylinder that can lead to piston sticking or leakage.
- Typically replaced during overhaul when inspection finds bore damage, out of tolerance wear, or contamination that cannot be corrected within approved limits.
Pressure relief performance directly affects constant speed governor response and repeatability, especially in aviation service where oil pressure behavior must remain predictable across temperature and load changes.
Installation notes
Always refer to the applicable aircraft and governor maintenance manual for complete installation procedures.
- Inspect the relief valve piston, spring, and seat surfaces for matched wear and replace components as required by approved overhaul data.
- Confirm the relief valve moves freely and complete the specified functional checks after assembly.
Applications and fitment
Used on McCauley governor assemblies where OEM B-20251 is specified. Confirm compatibility by matching the OEM part number and reviewing governor model and serial number applicability in approved maintenance data.
Tempest AGB-20251 is the direct replacement for OEM B-20251. Match the OEM part number and confirm applicability by governor model and serial number in the approved maintenance data.
Pilot John International supplies Tempest PMA propeller governor components to propeller overhaul shops, FBOs, MROs, and aviation maintenance technicians supporting aircraft maintenance and ground support.
| General Information | |
|---|---|
| Part # | AGB-20251 |
| Manufacturer | Tempest |
| Shipping Information | |
|---|---|
| Product Weight | 0.02 lbs. |
| Product Dimensions | 1 x 0.5 x 0.5 in. |
| Schedule B | 8807300010 |
| ECCN | 9A991.d |
| Specifications | |
|---|---|
| Approval | FAA-PMA replacement part |
| OEM P/N | B-20251 |
| System | McCauley propeller governor, pressure relief assembly |
| Tempest P/N | AGB-20251 |
| Type | Relief valve cylinder |
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AIRCRAFT COMPATIBILITY
| Compatible Aircraft* | |
|---|---|
| Cessna | 182 , 210 |
| Hawker Beechcraft | A24 , A24R - Sierra 200 , Beech Bonanza , Musketeer |
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QUESTIONS & ANSWERS
Tempest AGB-20251 is a direct FAA-PMA replacement for McCauley P/N B-20251. Always verify compatibility with your specific propeller governor model and applicable maintenance documentation before placing an order.
The Tempest AGB-20251 Relief Valve Cylinder is designed for use in aircraft equipped with McCauley model C290D3 propeller governors. Matching replacement parts to the correct governor model is essential to ensure proper fit, function, and reliable operation.
The Tempest AGB-20251 Relief Valve Cylinder houses the relief valve components and defines the pressure-regulating chamber. Proper cylinder condition is critical for accurate pressure control and system safety.
PJi offers the Tempest AGB-20251 as an FAA-PMA-approved replacement for the McCauley B-20251 relief valve cylinder. View our full selection of Tempest propeller governor parts to find the correct component for your application.
For a deeper look at how propeller governors work, why proper maintenance matters, and how to identify compatible replacement components, refer to our Ultimate Guide to Aircraft Propeller Governor Maintenance.
