The 78713-003 is a Piper OEM propeller feather stop plate assembly, used in the propeller control/feathering system to define and physically limit the feather position range of a constant-speed propeller system. It ensures that the propeller control linkage correctly reaches and stops at the designed feather detent, preventing over-travel of the mechanism.

In aircraft equipped with constant-speed propellers (such as Piper PA-34 variants and other multi-engine or complex light aircraft), the feather stop system is critical for ensuring proper propeller blade angle positioning during engine shutdown, engine-out conditions, or feathering procedures. The plate assembly works as a mechanical reference surface for the control system, helping maintain consistent and repeatable feather positioning.

The component is typically installed within or near the propeller control quadrant or associated linkage structure. It works in conjunction with cams, stops, and support channels to guide and limit motion of the propeller control lever or linkage system.

Manufactured to Piper OEM specification, the part is generally made from aircraft-grade aluminum alloy or steel, selected for strength, wear resistance, and long-term dimensional stability under repeated control movement and vibration.

Key features include:

Piper 78713-003 propeller feather stop plate assembly (OEM part)
Defines and limits propeller feather control travel
Used in constant-speed propeller control systems
Ensures correct feather position alignment and repeatability
Installed in propeller control quadrant or linkage assembly
Works with cams, brackets, and supporting structural components
Aircraft-grade aluminum or steel construction (application dependent)
Designed for high reliability in vibration-prone environments
Critical for proper feathering function in engine-out scenarios
Direct OEM replacement per Piper IPC specifications