Faulty rudder and inadequate response from the crew are pointed out as the major reasons for the crash of the Indonesian AirAsia A320, which disappeared from the radar December 28 last year killing 162 people on board.

Indonesian officials said Tuesday that the rudder control system of the airplane malfunctioned four times in flight QZ8501. That problem happened 23 times during the past year, according to a report by BBC. How the crew responded also added to the factors of the crash.

Before these findings, investigators initially blamed stormy weather why the flight from Surabaya to Singapore plunged into the Java Sea December 28 last year. However, reports now claim that this is not the cause.

In a report by Reuters, National Transportation Safety Committee (NTSC) investigator Nurcahyo Utomo said, "There was a chain of events, starting with a broken (part), how it was handled and then after it was handled what the consequences were and how the pilot handled it. It's difficult for me to say what the main cause was."

According to Yahoo, the NTSC points to poor maintenance and problems to the system that controls the movement of the rudder as the major reason for the crash. There was a crash in the soldering of the component making it malfunction. It sent repeated warnings to the pilots. However, Investigator Nurcahyo Utomo said the pilots flying the Airbus A320 didn't have enough training on what to do when the plane becomes very unstable, since the manufacturer didn't recommend it.

Data from the block box suggested that the crew could have shut off the computer that controls that rudder system. This is not supposed to be typically done, but the captain may have tried it after seeing ground crew try it on the same plane earlier. The captain has to leave his seat to pull this off; however, officials claim that there is no concrete evidence to the claim that the captain left his seat.