Pilot error was to blame for the July 23, 2014 crash of a TransAsia Airways ATR 72-500 that claimed 48 lives, Taiwan’s Aviation Safety Council (ASC) has determined. The twin turboprop crashed into a residential area while on approach to Magong Airport on Penghu Island, in the Taiwan Strait, during a thunderstorm.

Seven months later, a TransAsia ATR 72-600 crashed into Taiwan’s Keelung River after taking off from Taipei Songshan Airport, resulting in 43 deaths. The ASC continues to investigate that accident.

In a final report on the 2014 crash released on January 29, the council stated that “contrary to standard operating procedures” the pilots executed an approach to the airport below the minimum descent altitude (MDA) when they could not see the runway. The aircraft, operating as Flight GE 222, had departed from Kaohsiung International Airport on the Taiwan mainland with 58 passengers and crew on board. It collided with terrain 850 meters northeast of the threshold of Magong Airport Runway 20.

“Flight crew coordination, communication, and threat and error management were less than effective. That compromised the safety of the flight,” the ASC stated in a summary of its findings. “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. Rather, the first officer collaborated with the captain’s intentional descent below the MDA.” Neither of the pilots recognized the need for a missed approach until the aircraft reached the point where a collision with terrain became unavoidable, the council added.

The ASC report contains 29 safety recommendations. Among them, the council calls on aircraft manufacturer ATR to “evaluate the feasibility of a modification” to provide a new enhanced ground proximity warning system on all ATR 72-500s.