McCauley B-20077, Piston Relief Valve - Tempest PMA
Tempest AGB-20077-PMA
The Tempest AGB-20077 (McCauley OEM B-20077) is an FAA-PMA replacement piston relief valve for McCauley applications.
- Helps manage oil pressure behavior inside the governor piston circuit to support stable RPM control and predictable propeller response.
- Supports component protection by relieving pressure as designed, reducing the likelihood of harsh operation and internal wear.
- Commonly replaced during troubleshooting when symptoms point to sluggish response, inconsistent control, or pressure related issues, always following approved diagnostic guidance.
In constant speed governor systems, hydraulic control is everything. A relief valve that is worn, sticking, or out of tolerance can create performance issues that feel like a governor rigging problem. This Tempest replacement is supplied for aviation governor maintenance where accurate OEM cross referencing is critical.
Installation notes
Always refer to the applicable aircraft and governor maintenance manual for complete installation procedures.
- Maintain strict cleanliness, including lint free handling, because small contamination can affect valve seating and response.
- After installation, perform the functional checks required by the approved maintenance data to confirm correct governor response.
Applications and fitment
Used where OEM B-20077 is specified for McCauley governor piston relief valve applications. Confirm compatibility by governor model and serial number and consult the illustrated parts list and test procedures in approved maintenance data.
Tempest AGB-20077 is the direct replacement for OEM B-20077. Confirm applicability by governor model and serial number in the approved maintenance data before ordering or installing.
Pilot John International offers Tempest PMA propeller governor parts for propeller overhaul shops, FBOs, and aviation technicians to support aircraft maintenance and ground support.
| General Information | |
|---|---|
| Part # | AGB-20077 |
| Manufacturer | Tempest |
| Shipping Information | |
|---|---|
| Product Weight | 0.01 lbs. |
| Product Dimensions | 1 x 0.3 x 0.3 in. |
| Schedule B | 8807300010 |
| ECCN | 9A991.d |
| Specifications | |
|---|---|
| Approval | FAA PMA |
| Material and finish | Manufactured to the OEM relief valve specification. Confirm any spring rates, seat condition criteria, and inspection limits in the applicable McCauley governor manual. |
| OEM P/N | B-20077 |
| Tempest P/N | AGB-20077 |
| Type | Piston relief valve, McCauley governor hydraulic control component |
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AIRCRAFT COMPATIBILITY
| Compatible Aircraft* | |
|---|---|
| Cessna | 206 , 210 |
| Hawker Beechcraft | A24 , A24R - Sierra 200 , Musketeer |
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QUESTIONS & ANSWERS
Tempest AGB-20077 is a direct FAA-PMA replacement for McCauley P/N B-20077. Always verify compatibility with your specific propeller governor model and applicable maintenance documentation before placing an order.
The Tempest AGB-20077 Piston Relief Valve is designed for use in aircraft equipped with McCauley model C290D2 propeller governors. Matching replacement parts to the correct governor model is essential to ensure proper fit, function, and reliable operation.
The Tempest AGB-20077 Piston Relief Valve regulates maximum internal oil pressure within the propeller governor by opening when pressure exceeds a defined threshold. Proper relief valve operation protects internal components from overpressure and helps prevent RPM instability or overspeed conditions.
PJi offers the Tempest AGB-20077 as an FAA-PMA-approved replacement for the McCauley B-20077 piston relief valve. 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.
