Question about forensic engineers
 

I'm doing some writing based on the helicopter incident at 787 7th Avenue, and about an hour and a half after the crash, forensic engineers from the Department of Buildings arrived on scene.
https://www.youtube.com/watch?v=kSQV...QxcJ8&index=18
You can see them showing up here around 10:33

In an incident like that, where a building has taken some damage (but nowhere near catastrophic), what would a forensic engineer do when they arrived on scene? If the damage is confined to one area (like the roof) would it take long to do an initial inspection, or do they tend to be really thorough and take longer?