Asiana Airlines Flight 214’s pilots didn’t have a full understanding of the aircraft’s automated systems and “mismanaged” the approach to San Francisco International Airport (SFO), the US National Transportation Safety Board (NTSB) has concluded.

“The crew over-relied on automated systems that they didn’t fully understand,” NTSB acting chairman Christopher Hart said Tuesday during a public hearing releasing the board’s findings on the July 6, 2013 crash. The Asiana Boeing 777-200ER came down short of SFO’s runway 28L, hit a sea wall and crashed on landing. There were three fatalities and 49 serious injuries resulting from the crash, according to NTSB. One of the fatalities occurred when an emergency response vehicle ran over a passenger who had been ejected from the aircraft during the crash sequence.

But most of the 307 passengers and crew aboard survived the accident with no or minor injuries, which Hart said can be attributed to advances in aircraft safety. “In years past, [a similar crash] might have resulted in scores or hundreds of fatalities,” he said, noting that “fire blocking materials” gave passengers and crew the time to escape the fiery aircraft.

The NTSB placed blame for the crash on errors made by pilots Jeong-Min Lee and Gang-Guk Lee, who were at the controls when the aircraft attempted to make the landing on a clear day at SFO. Jeong-Min Lee was the pilot in command, sitting in the right seat and acting as an instructor to Gang-Guk Lee, a veteran pilot in the midst of transitioning to the 777 who was sitting in the left seat and controlling the aircraft.

Speaking of Gang-Guk Lee, NTSB senior air safety investigator Roger Cox said, “Although he was an experienced pilot, he lacked critical manual flying skills.” The pilot flying the aircraft “needed more active coaching,” Cox said. But even though the flying pilot was “showing poor awareness,” the pilot in command “did not intervene in time,” he added.

According to NTSB, the aircraft’s autopilot system was disconnected and the auto-throttles were in hold mode in the final portion of the approach when the aircraft’s speed became too slow. NTSB board member Robert Sumwalt, a former airline pilot, said the Asiana 214 flying pilot expected the auto-throttles would “wake up” if the 777’s speed became too slow.

“I personally don’t think this was a problem with crew competency,” Sumwalt said. “I think this is a case of the pilot thinking the airplane would do something for him that it was not designed to do.”

Sumwalt added that “it was not just this pilot who misunderstood” how the 777’s auto-throttles worked. He said that before the Asiana 214 crash, there was a “widespread” lack of understanding among 777 pilots about how the auto-throttles would respond in a similar situation.

“I think the expectation of the [Asiana 214] pilot was that the auto-throttles would take care of” flight speed, Sumwalt said, adding that the pilot “was astonished” the auto-throttles didn’t “wake up” when the aircraft’s speed became too slow.

Nevertheless, Cox pointed out that the flight’s 14 mile-approach to SFO was troubled throughout. “There are a lot of things the crew could have done to manage the approach much more smoothly,” he said.

NTSB concluded the flight crew “did not follow” standard operating procedures during the approach. During interviews with NTSB investigators following the crash, neither pilot recalled being aware of low airspeed until well below 500 feet, the board reported. NTSB cited the pilots’ “increased workload” and “fatigue” as possible factors in the crash.

NTSB was also critical of the emergency response to the crash at SFO. “There were numerous problems with communication during the emergency response,” the board said, noting the “lack of a common radio frequency” for emergency responders.