Final answer:
The duration of Second-Class Medical Certificate Privileges for a pilot who is under 40 years old is 12 months. Pilots need to renew their certificate regularly.
Step-by-step explanation:
The duration of Second-Class Medical Certificate Privileges for a pilot who is under 40 years old is 12 months. This means that the privileges granted by the certificate are valid for a period of 12 months from the date of issue.
After the 12-month period, the pilot will need to undergo a medical examination and obtain a new certificate to continue exercising the privileges.
It's important for pilots to regularly update their medical certificates to ensure they meet the medical requirements necessary to safely operate an aircraft.