FAA Powerplant Written Practice Test

What is a consequence of having sloppy weld beads in a reciprocating engine exhaust system?

1. Increased weight of the system

2. Local hot spots

3. Excessive back pressure

4. Decreased exhaust velocity

The correct answer is: Local hot spots

Having sloppy weld beads in a reciprocating engine exhaust system can create local hot spots. This is because irregularities in the weld can lead to uneven heat distribution. When weld beads are not consistent, it can cause certain areas of the exhaust system to be more prone to overheating, which can damage surrounding components and compromise the integrity of the exhaust system over time. Local hot spots may also result in thermal stress fluctuations, which can increase the likelihood of material fatigue and lead to premature failures in the exhaust system. The design and construction of exhaust systems require precise welds to ensure efficient heat dissipation and to maintain uniform temperatures throughout the structure. This is crucial for the overall performance and reliability of the engine. While the other options, such as increased weight, excessive back pressure, and decreased exhaust velocity, might seem plausible, they do not directly result from poorly executed welds in the same way that local hot spots do. The presence of hot spots is a specific and significant consequence of sloppy welding practices, affecting both safety and functionality.