Incident Overview
A repositioning flight lasting approximately 15 minutes reached a maximum altitude of 3,100 feet without cabin pressurization. The flight crew reported no unusual occurrences during the flight. However, a postflight inspection revealed that pallets from the 3L position had shifted aft and punctured the aft pressure bulkhead in two places.
Preflight and Cargo Securing
A flight mechanic stated that he had secured the pallets in positions 3L and 3R when they were placed there two flights before the incident flight. He reported that he 'flipped up three rows of locks aft of each pallet position.'
The flight engineer reported that during the preflight inspection, the left side of the pallet arrangement had an overhang, and he could not see the aft locks. He noted that the front locks were installed.
Inspection Findings
Postflight examination confirmed that the pallet shift had caused two punctures in the aft pressure bulkhead. No other damage was reported. The aircraft was not pressurized during the short flight, which limited the potential consequences of the bulkhead damage.