Investigation
Numerous public safety agencies responded to the crash including the Dallas/Fort Worth Airport Department of Public Safety, the Texas Department of Public Safety, the Irving Fire Department, the Irving Police Department and all available third watch personnel from the Dallas Police Department's Northwest Patrol Division and the Northeastern Sector of the Fort Worth Police Department's Patrol Division.
After a long investigation, the National Transportation Safety Board deemed the cause of the crash to be attributable to pilot error, combined with extreme weather phenomena associated with microburst-induced wind shear.
The NTSB attributed the accident to lack of the ability to detect microbursts aboard aircraft - the radar equipment aboard aircraft at the time was unable to detect wind changes, only thunderstorms. After the investigation, NASA researchers at Langley Research Center modified a Boeing 737-200 as a testbed for an on-board Doppler weather radar. The resultant airborne wind shear detection and alert system was installed on many commercial airliners in the United States after the FAA mandated that all commercial aircraft must have on-board windshear detection systems.
Read more about this topic: Delta Air Lines Flight 191