ATR72-500

- The flight crew did not comply with the published runway 20 VOR non-precision instrument approach procedures at Magong Airport with respect to the minimum descent altitude (MDA). The captain, as the pilot flying, intentionally descended the aircraft below the published MDA of 330 feet in the instrument meteorological conditions (IMC) without obtaining the required visual references.
- The aircraft maintained an altitude between 168 and 192 feet before and just after overflying the missed approach point (MAPt). Both pilots spent about 13 seconds attempting to visually locate the runway environment, rather than commencing a missed approach at or prior to the MAPt as required by the published procedures.
- As the aircraft descended below the minimum descent altitude (MDA), it diverted to the left of the inbound instrument approach track and its rate of descent increased as a result of the flying pilot’s control inputs and meteorological conditions. The aircraft’s hazardous flight path was not detected and corrected by the crew in due time to avoid the collision with the terrain, suggesting that the crew lost situational awareness about the aircraft’s position during the latter stages of the approach.
- During the final approach, the heavy rain and associated thunderstorm activity intensified producing a maximum rainfall of 1.8 mm per minute. The runway visual range (RVR) subsequently reduced to approximately 500 meters. The degraded visibility significantly reduced the likelihood that the flight crew could have acquired the visual references to the runway environment during the approach.
- Flight crew coordination, communication, and threat and error management were less than effective. That compromised the safety of the flight. The first officer did not comment about or challenge the fact that the captain had intentionally descended the aircraft below the published minimum descent altitude (MDA). Rather, the first officer collaborated with the captain’s intentional descent below the MDA. In addition, the first officer did not detect the aircraft had deviated from the published inbound instrument approach track or identify that those factors increased the risk of a controlled flight into terrain (CFIT) event.
- None of the flight crew recognized the need for a missed approach until the aircraft reached the point (72 feet, 0.5 nautical mile beyond the missed approach point) where collision with the terrain became unavoidable.
- The aircraft was under the control of the flight crew when it collided with foliage 850 meters northeast of the runway 20 threshold, two seconds after the go around decision had been made. The aircraft sustained significant damage and subsequently collided with buildings in a residential area. Due to the high impact forces and post-impact fire, the crew and most passengers perished.
- According to the flight recorders data, non-compliance with standard operating procedures (SOP's) was a repeated practice during the occurrence flight. The crew’s recurring non-compliance with SOP's constituted an operating culture in which high risk practices were routine and considered normal.
- The non-compliance with standard operating procedures (SOP's) breached the obstacle clearances of the published procedure, bypassed the safety criteria and risk controls considered in the design of the published procedures, and increased the risk of a controlled flight into terrain (CFIT) event.

The accident is due to the human factor. In particular, it was caused by an improper conduct of the aircraft by the PF (commander) during landing, not consistent with the provisions of the operator's manuals, in an environmental context characterized by the presence of significant criticality (presence of crosswind with values at the limit/excess those allowed for the ATR 72) and in the absence of an effective CRM.
The following factors may have contributed to the event:
- The failure to carry out the landing briefing, which, in addition to being required by company regulations, would have been an important moment of pooling and acceptance of information fundamental to the safety of operations.
- The maintenance of a V APP significantly higher than expected.
- The conviction of the commander (PF), deriving from his considerable general and specific experience on the aircraft in question, to be able to conduct a safe landing in spite of the presence of critical wind conditions for the type of aircraft.
- The considerable difference in experience between the commander and the first officer, which has reasonably prevented the latter from showing his critical capacity, thus rendering CRM techniques ineffective.