Final answer:
A First Class Medical certificate is needed by airline transport pilots and must be renewed periodically. If lost, a pilot must contact the FAA FSDO, fill out an application, and provide proof of identity to receive a replacement.
Step-by-step explanation:
A First Class Medical certificate is required for airline transport pilots (ATP) who must have a valid medical certificate to exercise the privileges of their pilot certificates. The First Class Medical is required to be renewed every 12 months for those under 40 years of age and every 6 months for those age 40 and over. If the certificate is lost, the pilot should contact the nearest Federal Aviation Administration (FAA) Flight Standards District Office (FSDO) to apply for a replacement. The process involves completing an application for a duplicate, providing proof of identity, and possibly a fee. The FAA will then issue a replacement certificate.