A team of U.S. investigators including representatives from Boeing have examined the site of a plane crash that killed 179 people in South Korea.

The Jeju Air crash has raised concerns about the design of a South Korean airport and whether a concrete-reinforced mound beyond the runway played a significant role in one of the deadliest plane accidents in recent years.

Empty desks and a calendar marking days off after Christmas sit in a South Korean office where five co-workers once planned a holiday to Thailand which ended in tragedy on Sunday when their return Jeju Air flight crashed.