What is the maximum RPM drop allowed on an Archer aircraft?

In the context of the Piper Archer aircraft, the maximum allowable RPM drop during the engine run-up is indeed 175 RPM. This figure is established as part of the manufacturer's specifications and guidelines for engine performance and safety checks.

When performing a run-up, which typically occurs prior to takeoff, pilots are required to conduct specific checks to ensure the engine’s reliability and overall operational status. During this process, the pilot will engage the propeller to verify its functionality, which includes checking for a drop in RPM when switching from the “both” position of the ignition system to a single magneto.

A maximum RPM drop of 175 RPM indicates that the engine is likely operating within acceptable limits, allowing for effective ignition and combustion on both magnetos. A drop that exceeds this threshold could indicate a potential issue with either the ignition system or engine health, necessitating further investigation before flight.

Understanding these operational parameters helps ensure safety and readiness of the aircraft for flight, as it verifies that all critical engine components are functioning properly.