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_31248 ( "No. in series" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" real )

### Question ###
What date did the episode that was directed by Christian i. nyby ii originally air on?

### Accurate SQL ###

SELECT "Original air date" FROM table_31248 WHERE "Directed by" = 'Christian I. Nyby II'