Final answer:
A pilot aged 43 flying single-pilot VFR needs to pass a medical examination every 6 months to maintain a Category 1 medical certificate. The frequency of exams increases from every 12 months to every 6 months once the pilot reaches the age of 40.
Step-by-step explanation:
A 43-year-old pilot flying single-pilot VFR (Visual Flight Rules) in a commercial operation can maintain a Category 1 medical certificate by undergoing regular medical examinations as per aviation regulatory requirements. In the United States, for instance, to hold a Category 1 medical certificate, the pilot must pass a medical examination every 12 months if they are under the age of 40. However, when the pilot is age 40 or older, the duration for which the medical certificate is valid decreases to 6 months for operations requiring a first-class medical certificate. It is crucial for the pilot to ensure they are in good health and fit to fly, as failing to maintain a valid medical certificate could compromise flight safety and may be a violation of aviation regulations.