Updated

A University of Utah engineering professor charged with viewing child pornography on a flight to Boston has been freed on bail.

Boston authorities say 47-year-old Grant Smith of Cottonwood Heights, Utah, posted $75,000 bail Monday. His defense attorney declined to comment Tuesday.

Smith pleaded not guilty to child pornography possession Dec. 1. A judge ordered him to surrender his passport, avoid unsupervised contact with children and not to use the Internet except for work. A prosecution spokesman said Smith is allowed to leave Massachusetts. He's due back in court Dec. 27.

Prosecutors said a fellow first-class passenger saw Smith viewing the images Nov. 26 and took a cellphone photo before alerting a flight attendant. Smith was arrested after arriving in Boston.

The university has placed him on administrative leave.