Mask required for crew members?
This question relates to 135 operations, as part 91 operations appear to be exempt from the new CDC/TSA mask requirement.

Your Feb 4 article indicates that "FAA officials have confirmed that required crewmembers are exempt from mandatory mask-wearing on the flight deck when in their duty status by virtue of the “workplace safety guidelines” exemption in the CDC order."

Can anyone provide a source document for this exemption?

Thank you!