Page 7 of the Civil Aeronautics Board Aircraft Accident Report describes the United Flight 823 Flight Recorder as being a Lockheed Aircraft Service Model 109C. Serial Number 578.
The recorder was installed in the electrical compartment below the cabin floor at Fuselage Station (FS) 389.
The recorder shell was crushed and separated due to shear loads to approximately 1/2 its original diameter. The aluminum recording tape, being exposed to the ground fire that took place after the crash, was destroyed. This was the first recorded instance of tape inside a flight recorder being destroyed by fire. As a result, no usable information was available.