Final answer:
A facsimile replacement for an airman's medical certificate is valid for a maximum of 60 days from the date of issue, serving as a temporary authority during formal replacement processing.
Step-by-step explanation:
When an airman receives a facsimile replacement of their medical certificate, it serves as a temporary authority to exercise the privileges of their airman certificate. The facsimile replacement is valid until the end date specified in the authorization, which cannot exceed 60 days from the date of issue. This temporary period allows the airman to continue operating under the privileges of their certificate while the official replacement is processed and shipped. It's important to understand that this is a stop-gap measure and not a long-term substitute for the formal, permanent medical certificate.