What is required to add a multiengine class rating to an existing private or commercial pilot certificate?

To add a multiengine class rating to an existing private or commercial pilot certificate, the requirements include successfully completing a practical test and obtaining a logbook endorsement. There is no specified minimum dual or solo flight time required for this addition, allowing for more flexibility in the training process.

The practical test assesses the pilot's proficiency in operating multiengine aircraft, while the logbook endorsement confirms that the pilot has completed the necessary training and is deemed competent to operate multiengine airplanes. This approach emphasizes the applicant’s demonstrated skills rather than a strict quantification of flight time.

The other options suggest requirements that either specify unnecessary flight hours or imply the need for a knowledge test, which is not mandated when solely adding a multiengine rating. This understanding helps pilots focus on the skills needed for multiengine operations rather than getting bogged down by specific time constraints.