Six Examples of Aircraft Engine Tests and Inspections

Aircraft engines are as complex as they are cost-intensive. Operating them correctly is only one part of engine management. Recognizing when something is wrong, identifying the affected area, and selecting an appropriate method to assess the condition are equally important.

Different engine tests and inspections serve different purposes. Some evaluate how the engine performs while operating, while others focus on external condition, visible internal areas, or discontinuities within specific materials and components. The results can then be compared with the relevant maintenance limits or acceptance criteria to determine whether further action is required.

Below are six examples of tests and inspections used to assess aircraft engine performance and condition.

1. Test Cell

• Purpose: Assess engine performance and operating condition following maintenance or overhaul.

• Method: Run the engine on an instrumented test stand through prescribed power settings and operating checks.

• Results: Record thrust, EGT, fuel flow, vibration, rotor speeds, and specified oil-system, temperature, and pressure readings. Calculate corrected performance and EGT margin, then compare the results against applicable acceptance criteria.

  
  

2. External Visual Inspection

• Purpose: Assess the engine’s external condition, component completeness, and configuration.

• Method: Examine accessible surfaces, components, and attachments. Where applicable, verify part and serial numbers against configuration requirements and records.

• Results: Document visible cracks, corrosion, dents, leakage, loose attachments, missing parts, and identification or configuration discrepancies.

  
  

3. Borescope Inspection

• Purpose: Assess the visible condition of internal engine areas without full disassembly.

• Method: Use an optical or video probe to inspect accessible compressor, combustion chamber, and turbine areas.

• Results: Document cracks, erosion, dents, foreign object damage, burning, and coating loss. Assess the findings against applicable maintenance limits to determine acceptability and required follow-up.

4. Ultrasonic Testing

• Purpose: Assess material integrity beneath the surface of suitable engine components.

• Method: Transmit high-frequency sound waves into the material and evaluate the returned signals.

• Results: Identify and characterize internal discontinuities such as cracks and voids. Depending on the application, this method may also measure thickness or detect delamination and disbonding in composite structures.

5. Eddy Current Testing

• Purpose: Assess electrically conductive components for surface and near-surface discontinuities.

• Method: Use an electromagnetic probe to induce eddy currents and detect changes in the material’s response.

• Results: Identify and characterize indications of cracking or other discontinuities, including around holes, edges, and areas prone to fatigue damage.

6. Fluorescent Penetrant Inspection

• Purpose: Detect surface-breaking discontinuities in nonporous components.

• Method: Apply fluorescent penetrant to a clean, accessible surface, remove the excess penetrant, apply developer, and examine the area under UV-A light.

• Results: Reveal and document fine cracks and other surface-breaking indications that may be difficult to detect through an ordinary visual inspection. Evaluate the indications against applicable acceptance criteria.

Selecting the Appropriate Method

Each method provides a different view of engine condition. A test cell evaluates operating performance, while visual and borescope inspections assess accessible external and internal areas. Ultrasonic, eddy current, and fluorescent penetrant inspections help identify discontinuities that may not be visible through an ordinary inspection.

Together, these methods support a more informed assessment of engine performance, component condition, and required maintenance follow-up.

Making the Right Engine Decision

Engines are high-cost, high-risk assets. The right technical and records expertise is essential before making the call.

Drop us an email at info@tbmaviation.com  for engine management and technical support across Indonesia, Southeast Asia and beyond.