FAA Powerplant Written Practice Test

What are the signs that an engine part might need to be replaced during an overhaul?

1. Visual discoloration

2. Surface wear beyond limits

3. Rattling noises

4. Temperature fluctuations

The correct answer is: Surface wear beyond limits

When evaluating engine parts during an overhaul, surface wear beyond specified limits is a crucial indicator that a component may need to be replaced. Engine parts are designed with specific tolerances and surface finishes that ensure efficient operation and reliability. When wear occurs beyond these limits, the performance of the engine can be compromised, leading to potential failure or inefficiency. Surface wear can be examined through various methods, including measurements with calipers or other precision tools, and visual inspection to identify abnormal patterns, scoring, or pitting. If a part exhibits wear beyond the manufacturer's specifications, it is typically deemed unserviceable, necessitating its replacement to maintain engine integrity and performance. Other signs, while they may indicate certain issues, do not directly point to the need for replacement in the same way. Visual discoloration can be caused by overheating or specific operational conditions but may not necessarily mean the part is beyond safe operational limits. Rattling noises may suggest a loose component but can sometimes be remedied without part replacement. Temperature fluctuations might indicate various problems, including sensor issues, but do not directly assess the condition of the engine parts in terms of wear limits. Thus, noticing wear that exceeds allowable specifications is the most definitive sign indicating that a part should be replaced during an overhaul.