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_17467447_1 (original_airdate VARCHAR, us_viewers__million_ VARCHAR)

### Question ###
What is the air date when the U.S. viewers was 5.50 million?

### Accurate SQL ###

SELECT original_airdate FROM table_17467447_1 WHERE us_viewers__million_ = "5.50"