There might have been numerous inspections done on the aircraft and it may have had a lot of technical incidents but I don't believe that this accident happened due to technical failures.
The following is from a previous post which in my opinion is very close to the truth about what happened in the accident:
There was no electrical problem, no radio failure, no toxic gases, no hijacking nor any other kind of actual problem. The aircraft behaved perfectly. What happened is that the outflow valve was left on Manual by the engineers that carried out the pressurization check during the previous night. The valve’s wrong position was missed by the flight crew during the overhead scan and during the checklists. It’s not unthinkable, it happened before and it will happen in the future.
The Equipment cooling light came on and did not go out when 'Alternate' was selected, simply because the intake pressure was low since there was no cabin pressurisation. (The EE light is triggered by a low pressure sensor in the equipment cooling duct.) The QRH says: 'IF THE LIGHT DOES NOT GO OUT WHEN ALTERNATE IS SELECTED, NO FURTHER ACTION IS REQUIRED'.
The flight crew were dealing with this 'problem' when the cabin altitude warning (intermittent horn) came on. They then probably considered that this was a false take-off configuration warning (the two warnings are exactly the same) caused by the equipment cooling problem. The captain probably stood up to look at the circuit breakers, probably to try and reset the EE cooling sensor circuit breakers. While they were trying to figure it all out the aircraft was climbing and they were suffering progressive hypoxia due to the high cabin altitude, which impairs reasoning.
At 14000 ft cabin altitude, the cabin masks dropped. Cabin crew are told not to contact the flight deck immediately in such cases, due to high workload of the pilots. The warning for the oxygen masks in the FD is a light in front of the pilots saying ‘overhead’, same as for the EE cooling light! The oxygen masks light though on the overhead panel is much further aft on the panel than the EE cooling light though. Thus this warning was probably totally dismissed by the crew as a repetition of the EE cooling warning.
Therefore the flight crew were totally unaware that there was a pressurization problem while the cabin crew and passengers were on oxygen masks from 14000 ft onwards. Once the flight crew were unconscious there was no way to enter the Flight deck since the door was locked, unless the crew knew the code. Only the senior CC member would know the code, unless the code was changed and the crew was not informed. Maybe the senior was unconscious or panicked or forgot the code. Who knows. We may never find out. When both engines flamed out and electrical power was lost, the door unlocked and the cabin crew that survived on the portable oxygen cylinders entered the cockpit.
So to sum it up, this accident was caused by a series of human errors alone. The aircraft behaved as if it was brand new.