Airline pilot here. This film is painful to watch for a pilot, as it plays very loosely with the physics and mechanics of the aircraft and how it is crashed (and flown during that crash). That sequence is then followed by many gross errors and omissions in NTSB investigation techniques, Union posturing and presentation of the "lifestyle" of pilots and crew and a perception they would cover for each other in such a criminal event.
But if you are the typical layman, the crash is gripping and spectacular, and the drama that follows is compelling, if not stilted. Denzel's acting, as always, is top notch, as is the overall message of abuse, dependency and the hard road to recovery. It is just unfortunate they didn't have better technical advice to easily bring accuracy and authenticity to a fine underlying story arc.