A Skywest Canadair CRJ-700 on behalf of United, registration N740SK performing flight OO-5336/UA-5336 from San Francisco,CA to Portland,OR (USA), was climbing out of San Francisco when the crew stopped the climb at FL230 reporting a problem with the windshield heating. The aircraft returned to San Francisco for a safe landing about 35 minutes after departure. The aircraft departed again after maintenance but about 20 minutes into the flight the aircraft levelled off and the captain announced they needed to return to San Francisco because the heating at the first officer's windshield had failed preventing them from continuing to Portland where icing conditions were expected. The crew provided an "aerial tour of the San Francisco Bay Area for the passengers" and landed safely back. A replacement aircraft was already waiting at the next gate and reached Portland with a delay of about 2 hours.
The attached audio clip covers the first incident and the aircraft departing SFO the second time. It also includes a Skywest FL5925 go around which occurred at the same time.
