Who is Doug Doherty, Nguyen Van Trung, Ron Smith, and Mike Lee from Airframe and what is their importance?

Less than an hour after TransPacific Flight 545 lands at LAX, the vice president of Norton Aircraft assembles a team to investigate the cause of the fatal flight. This team includes Casey Singleton, head of Quality Assurance. It also includes several engineers. Doug Doherty is in charge of structure and mechanical. Doherty will inspect the airframe to determine if a defect exists or was caused by the accident and how this fits in to the investigation. Nguyen Van Trung is in charge of avionics and will try to reenact the accident with the help of the many recorders on board the plane during the flight. Ron Smith is in charge of electrical. Ron is an introvert who is brilliant and will be a great help to Casey when it comes to interpreting some of the data they will take from the flight recorders. Finally, Mike Lee is a representative of TransPacific, the airline that owns the N-22 involved in the flight. Lee is a liaison between the team and the airline. However, Lee has his own agenda, mainly protecting his employer, and Casey often finds him more of a hindrance than a help.