Investigation Summary
Flight 458 was operating the final leg of a multi-stop route from Milwaukee to Chicago, running approximately 62 minutes behind schedule due to weather and baggage delays. During the ILS approach to Runway 14R, the weather was reported as a 200-foot ceiling with light rain and fog. Flight data and cockpit voice recorders indicated the approach was stable until the aircraft reached 210 feet, roughly 4,500 feet from the runway threshold. At this critical transition point, the aircraft began a continuous 11-second climb. The captain then called for a go-around, but the nose-high attitude led to a rapid loss of airspeed. The Convair CV-580 stalled 13 seconds after the go-around was initiated, entered a steep left bank, and impacted the North Central Airlines hangar. The left wing struck the ramp 100 feet in front of the hangar before the aircraft crashed into the bay in a near-inverted position, sparking a massive fire. While 18 people on board survived (17 passengers and one flight attendant), 27 occupants (24 passengers and 3 crew) and one person on the ground were killed.
Final Conclusions
The National Transportation Safety Board (NTSB) released its final report on November 12, 1970. The board concluded that the probable cause was spatial disorientation of the captain, precipitated by atmospheric refraction of the approach or landing lights. This optical illusion occurred at the critical moment when the crew was transitioning from instrument references to visual ground references. The NTSB also noted that the captain had limited experience as pilot-in-command on the CV-580 type, which may have hindered his ability to recognize the impending stall and recover the aircraft.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Had relatively limited experience as pilot-in-command on the CV-580.
First Officer
Systems & Failure Modes
Allison Prop-Jet Conversion
The CV-580 was a conversion of the Convair 440, replacing piston engines with Allison 501-D13 turboprops, significantly increasing power and performance.
Flight Data Recorder (FDR)
The FDR provided critical data showing the 11-second sustained climb and subsequent speed decay prior to the stall.
Interesting Facts
- 01The aircraft was originally built as a CV-440 Metropolitan in 1956 and converted to a CV-580 in July 1968.
- 02One person on the ground, a member of a boys' drum and bugle corps practicing in the hangar, died nine days after the crash.
- 03In addition to the ground fatality, six to seven other individuals on the ground sustained injuries when the aircraft struck the hangar.
- 04The hangar's deluge fire suppression system was credited with preventing further loss of life and controlling the post-crash fire.
- 05The captain had relatively few hours as pilot-in-command in the CV-580 at the time of the accident.
Safety Actions & Advisories
High Minima Landing Requirements
The NTSB recommended that the FAA amend regulations to require pilots to have more flying hours and landing experience in a specific aircraft type before being released from 'high minima' landing restrictions.