What happened
A non-scheduled domestic cargo flight, operating under instrument flight rules (IFR) as a Part 121 operation, departed for its intended destination. During the departure phase of the flight, the crew experienced a failure in the aircraft's cabin pressurization system. Due to this loss of pressure, the flight crew elected to return the aircraft to the departure airport.
The investigation
An FAA inspector conducted an examination of the aircraft following the return to the airport. During the inspection, maintenance personnel identified a penetrating gouge located on the right lower portion of the fuselage, situated between the wing and the tail near the cargo door. This specific damage measured 18 inches in length and between 1 to 2 inches in width. Additionally, the inspector noted other shallower surface skin damage approximately 3 feet in length. The investigation determined that the characteristics of this damage were consistent with contact from the counter-balance weight on a deicing truck used previously on the aircraft.