For which of the following is a PCC required?

In aviation, a Pilot Competency Check (PCC) is typically required for certain operations that demand a higher level of pilot proficiency and adherence to regulations. The correct scenario here involves the operation of multi-engine aircraft under more demanding conditions such as night VFR or IFR, where a PCC ensures that the pilot can handle the increased complexities and potential risks associated with flight operations in those circumstances.

For single-engine aircraft operating under day VFR, the requirements are generally less stringent because the conditions are typically more favorable, and the operational risks are lower. Therefore, a PCC is not mandated for this scenario, making it incorrect to claim that a PCC is required.

In contrast, multi-engine operations and commercial flights inherently require higher proficiency due to the complexity of the aircraft systems and the nature of commercial operations, where safety and regulations are paramount. The option that discusses night IFR requirements hints at the necessity of a PCC due to the increased workload, task saturation, and potential for reduced visibility associated with flying at night and under instrument conditions.

Thus, the requirement for a PCC is clearly tied to the operational complexity and risks, which are not present in the scenario involving single-engine aircraft under day VFR conditions.