Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_26817 ( "Episode no." real, "Airdate" text, "Viewers" real, "BBC Three weekly ranking" text, "Cable rank" text )

### Question ###
When 656000 is the amount of viewers and n/a is the cable rank what is the airdate?

### Accurate SQL ###

SELECT "Airdate" FROM table_26817 WHERE "Cable rank" = 'N/A' AND "Viewers" = '656000'