https://github.com/jleetutorial/sparkTutorial/blob/e6b73d4565ea07bb7d0aeaa7a54fc67c78651c83/src/main/java/com/sparkTutorial/rdd/airports/AirportsByLatitudeSolution.java#L19 This returns airports with latitude > 40, not airports in USA. The variable name `airportsInUSA` looks like a typo.