What happened
On July 17, Braniff Airways Flight 560 was operating a scheduled multi-stop service from Dallas, Texas, to Chicago, Illinois. The flight included stops in Oklahoma City, Wichita, and Kansas City. During the segment between Wichita and Kansas City, a minor carburetor intake manifold fire occurred during engine start, but it was quickly extinguished without causing damage. Upon landing in Kansas City, the crew noted that the number one propeller had feathered; however, after the captain manually unfeathered the propeller, no mechanical issues were identified by maintenance personnel.
After refueling in Kansas City, the aircraft departed at 0035 under visual flight rules. The flight was operating a turboprop aircraft with a gross weight of 45,622 pounds. During the final leg toward Chicago, the crew transitioned to instrument flight rules. As the aircraft approached the Chicago area, weather reports indicated visibility had dropped to one-half mile due to fog. The crew confirmed they could proceed with landing despite these conditions.
While executing an ILS approach to runway 13R, the aircraft was being radar vectored by Midway Approach Control. At approximately 0624, the aircraft struck an advertising sign and its steel support post roughly 1,000 feet before the runway threshold. The impact caused the plane to crash through the airport boundary fence onto the airfield. There were 3 fatalities among the crew and passengers.
Findings
Investigations into the crash determined that all navigational aids, including ILS components and ground lighting, were fully operational. No mechanical failures or emergencies were found within the aircraft prior to the impact. The accident was attributed to momentary disorientation caused by the loss of visual reference during the final visual portion of the approach, which led to an excessive rate of descent at an altitude insufficient for recovery.