Chan recalls that he retraced the route of the injured boy, including also taking the CZ6820 flight, and interviewed most of the people who had participated in the rescue.
As the movie's ending is known, Chan reveals his top challenge revolved on re-creating the nervous, yet endearing moments, as realistically as possible.
Starring actress Li Bingbing as the flight's chief attendant, actor Huang Xiaoming as the pilot in command, and actor Feng Shaofeng as the surgeon in charge of saving the arm, all the A-list stars had studied with those in the real-life situations to obtain professional knowledge, giving them a greater understanding of their characters.
Interestingly, all the other members of Feng-starring orthopedist's surgical team in the movie are doctors and nurses at the Urumqi hospital who were involved in the surgery.
"Aside from the operating room that was built on set, all the surgical accessories and medical equipment are real. The hospital was very helpful and supportive," says the director, adding that their effort gives a "documentary-like sense of reality" to the movie.
