When does a third class medical certificate issued to a 19-year-old pilot expire if issued on August 10?

A third class medical certificate issued to a 19-year-old pilot remains valid for a specified duration based on the age of the certificate holder at the time of issuance. According to FAA regulations, a third-class medical certificate is valid for 60 months (5 years) for individuals under 40 years of age. Since the pilot is 19 years old when the certificate is issued on August 10, it will remain valid until August 31, 5 years later.

This is because the certificate automatically expires at the end of the 60-month (5-year) period since the requirements state that the expiration date is placed at the end of the month in which the certificate was issued. Thus, while the certificate was issued on August 10, it will be valid through the end of August 5 years afterward, marking August 31 as the expiration date.