Final answer:
If ADR 1 is lost on the Captain's PFD, certain information about airspeed, altitude, and vertical speed would be lost.
Step-by-step explanation:
If ADR 1 is lost on the Captain's Primary Flight Display (PFD) in an aircraft, certain information would be lost.
ADR 1 generally refers to the Air Data Reference system, which provides information about the aircraft's airspeed, altitude, and vertical speed. If ADR 1 is lost, the Captain's PFD would no longer display this information accurately.
Without the accurate information provided by ADR 1, the Captain may have to rely on alternate methods or instruments to determine airspeed, altitude, and vertical speed.