Large Transport; Low Wing; 3 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
General Maintenance Action
Aircraft; Human Factors
While at cruise at FL260 we heard a very loud noise something like a loud bang [or] explosion. At first; we believed it was a compressor stall but while monitoring the engines [a] few minutes later the crew heard another loud noise with no change whatsoever in engine readings; hydraulic readings; electrical readings; smoke/fire detection indications etc. After cleared to descend to FL240 another couple of loud noises were heard by the crew and mechanic on board. When cleared to descend to 12000 ft we heard 3 or 4 loud noises. The noises were not consecutive at all; they were rather sporadic. From 12000 ft to landing no other loud noises were heard. After landing I informed Dispatch and Maintenance Control of the loud noises and we all proceeded to thoroughly inspect the airplane in its entirety. While conducting [the] inspection the Lead Load master informed me that they had encountered several floor locking devices sheared and broken apart. It wasn't until we saw the locks broken that we were able to figure out and assess the origin of [the] noises. Improper loading and securing of ULDs at departing airport.
Captain of a cargo aircraft reported noticing loud noises in cruise flight that were later determined to be related to broken floor locking devices.