Some Background Information
For those who don't want to trawl through all the documentation, some basic information about the Lockheed Electra.
The aircraft is a four engine turboprop which first entered service in January 1959. The aircraft had a very good power to weight ratio with short wings and huge propellers giving very good short field performance.
Two notable accidents in September 1959 and March 1960 were attributed to wing failure caused by the gyroscopic forces from the propeller disks causing the engine mounts to fail. This whirl mode failure was addressed by strengthening the wing and engine mounts and by altering the mountings to run the engines at an angle of three degrees in relation to the wings.
Four other accidents could be attributed to crew handling errors and one to bird strike where three of the four engines were affected.
The seventh accident (this one) occured in September 1961 at Chicago O'Hare airport as the aircraft climbed after take off. The aileron control cable separated leaving the aircraft with a full right wing low input. The aircraft initially climbed but the roll command could not be counteracted by the crew and the plane eventually crashed.
At present, only summary reports of the accident and press photos appear to be available to re-examine what happened. The summary reports appear to have some conflicting information regarding the final few seconds of the flight and the final disposition of the wreckage.
Did the pilots have any measure of control over the aircraft?
Did they somehow manage to attempt a belly landing?
The documents available so far, do not support this idea, but some of the data in the accident summaries has been given without context or supporting data.
There is no evidence that the investigators at the time took any shortcuts in the investigation, or that a less than thorough job was carried out. It is an unfortunate fact that no comment on the pilot's performance appears in the documents currently available.
Public confidence in the Lockheed Electra was severely damaged by this series of accidents and no further airframes were built after 1961.
It is significant that remedial upgrades and strengthening of the aircraft were so successful that it was not until 1971 that another incident involving structural failure of a Lockheed Electra in a thunderstorm occured.
Out of a total of 170 airframes built, 58 remain in service or could be restored to flying condition. The US Navy anti submarine patrol aircraft and NASA storm chaser aircraft are based on the Lockheed Electra airframe, which gives a measure of just how successful and robust the aircraft became.