What cool-down period is required after third to fifth engine starts on the ground?

The correct answer indicates that a 5-minute cool-down period is required after the third to fifth engine starts on the ground. This procedure is crucial for ensuring engine health and longevity.

During engine starts, the thermal stress and wear on engine components increase due to a number of factors, including temperature fluctuations and the engine’s operational limits. After multiple starts in succession, allowing a cool-down period helps to dissipate residual heat build-up, reduces the risk of overheating, and allows engine components to return to their optimal temperature.

The specific duration of 5 minutes balances engine safety with operational efficiency, minimizing downtime while ensuring the engines remain within acceptable thermal limits. This practice contributes to enhanced reliability and performance of the engine by preventing potential damage that could occur if the engine was restarted without adequate cooling.