After overhaul, how are engine diagnostics re-validated and what tests comprise acceptance?

• A. Electrical continuity test of wiring harness
• B. Visual inspection only
• C. Run-in and performance test; verify fuel control calibration, thermal stability, fuel flow, oil pressure, and vibration
• D. Static pressurization test of the fuel system

Answer: (C)

After overhaul, diagnostics are re-validated through a run-in and performance test that exercises the engine under operating conditions to confirm it meets specification. The run-in helps components such as bearings and seals seat properly and reveals early lubrication or clearance issues, while the performance test evaluates how the engine responds across the operating range. Central to acceptance is verifying the fuel control calibration so the metering unit delivers the correct fuel flow for the throttle and power settings, and confirming thermal stability so temperatures stay within limits during steady and transient operation. You’ll also check fuel flow to ensure delivery matches demand at different speeds, oil pressure to confirm proper lubrication across the range, and vibration to ensure rotor dynamics and mounting remain within limits. Together, these tests verify both mechanical integrity and control system performance after overhaul. Relying on only visual inspection, static fuel system pressurization, or isolated electrical tests would not adequately confirm dynamic performance, calibration, and thermal behavior needed for acceptance.