Background
Capital Airlines Flight 141 was a regularly scheduled flight from Willow Run Airport, Detroit, Michigan, to Chicago. The flight crew included Captain Roger Harrison Taylor, First Officer George Richard Hanst, and Stewardesses Jacqueline V. Sadowski and Gloria Galloway. Captain R. E. Gilliland was deadheading and rode in the passenger cabin. The aircraft departed Detroit at 0700 after a weather briefing and a VFR flight plan were filed. The gross takeoff weight was 54,701 pounds, below the specified limit, and the load was properly distributed with respect to the center of gravity.
Flight History
The flight to the vicinity of Chicago was routine. Near Chicago, Flight 141 reported to the tower that it was over the shoreline. The flight later reported passing Kedzie and was cleared to land on runway 31R. The aircraft was observed to make a right turn to final approach and appeared to descend normally until over the west side of Cicero Avenue, the eastern boundary of the airport, at an altitude of 25 to 50 feet above the ground.
Accident Sequence
At that point, the airplane appeared to decelerate and descend rapidly. It struck the ground in a slightly nose-up attitude several hundred feet short of the runway threshold. The top of the fuselage was seen to break open adjacent to the wing spar to fuselage attachment. As the aircraft proceeded down the runway, the landing gear retracted, and the aircraft slid on its belly until coming to rest to the left of the runway, 1,626 feet beyond the point of initial impact.
Aftermath
All occupants left the aircraft through emergency exits or the main cabin door. The fire department arrived at the scene before all persons had evacuated, but there was no fire. The Chicago weather at 0720 was reported as sky clear, visibility 6 miles with smoke, and wind north-northwest.
Probable Cause
The official investigation determined the probable cause to be a malfunctioning of the propeller control switches, which culminated in an abrupt loss of lift. Specific findings included that three of four landing gear actuated switches were capable of malfunctioning by jamming, sticking, or freezing; no periodic internal inspection of these switches had been established by the company; at least two switches malfunctioned, allowing the 21-degree pitch stops to be withdrawn and ineffective; the crew failed to see the 21-degree pitch warning light; during final approach, the propellers moved to the ground fine pitch range; when the first officer saw three of the 17-degree pitch warning lights come on, he advanced all four throttles quickly; the rapid throttle advance caused the propeller governor to move the blades to the four-degree pitch position, creating both propeller drag and loss of wing lift.