Final answer:
A third class medical certificate issued to a 19-year-old pilot on August 10 will expire at midnight on August 31, five years after the issuance, as per the FAA regulations for individuals under the age of 40.
Step-by-step explanation:
The question pertains to the expiration date of a third class medical certificate issued to a 19-year-old pilot. According to the Federal Aviation Administration (FAA) regulations, for individuals who are under the age of 40 at the time their medical certificate is issued, a third class medical certificate is valid for the remainder of the month of issuance plus 60 months (5 years). Therefore, if a third class medical certificate was issued to a 19-year-old on August 10 of the current year, it would expire at midnight on August 31, five years later.
It is important for pilots to be aware of the expiration dates of their medical certificates to maintain the privileges of their pilot certificates. In this case, the expiration would be at midnight on August 31st, five years after the issuance of the certificate.