Ground status

Which ground was actually looked at, and which was not. A sector is only searched when the crew believes a person on that ground would have been seen. Anything less is partial or unable, with the reason recorded — because a map that cannot say “unable” gets read as “clear”.
This is the crew’s report, not a probability of detection, and not a closure. Closing a segment is the search manager’s decision.

Coverage is reported by the crew, not read from aircraft telemetry. Every hand-over packet says so, and names every sector that is not a clean “searched”.