Final Report Lion Air Flight 904 – Pilot Error

The final report into the crash of a Lion Air Boeing 737-800 aircraft on short finals to land at Denpasar’s Ngurah Rai International airport on 13 April 2013 has identified several safety issues around the skill of the pilots and the carrier’s emergency response procedures.

The National Transportation Safety Committee (NTSC) report retains the same chronology as the preliminary report issued in May 2013. As with the earlier report, it highlights the failure of the captain and first officer to communicate effectively prior to impacting the water. The final report also refers to CCTV footage, which shows the extent of the rainy weather immediately prior to the crash, which prevented the flight crew from seeing the runway.

The first officer, who was flying, mentioned that the runway was not in sight as the aircraft descended through 900ft on final approach after an uneventful flight from Bandung. Although the aircraft’s automated systems issued a “minimum” warning at 550ft, the crew disengaged the autopilot and autothrottle, and continued the descent flying manually.

At 300ft, the report reveals that the cockpit voice recorder picked up a sound consistent with rain hitting the windshield, although there was no sound of windshield wipers. When the 737 had descended to just 150ft, the captain took control of the aircraft, while the first officer again said that he could not see the runway.
During interviews, the captain maintained that he was confident the runway would appear at any moment. It was only when the enhanced ground proximity warning system called a 20ft height alert that the pilot commanded a go-around but, just 1s later, the aircraft impacted the water. Though there were no fatalaties among the 101 passenges and seven crew, four passengers suffered serious injuries. The aircraft, bearing registration PK-LKS, was a complete hull loss.

“The (pilot in command’s) expectation that he would be able to see the runway after the rain can be considered as inability to accurately perceive what was going on in the flight deck and outside the aircraft, including the thunderstorm formation that was observed at an aircraft altitude below 900ft. This might be due to unutilised resources available in the flight deck and the limited visibility due to the hazy conditions which made the pilot unable to see the thunderstorm formation properly.”

The report makes it clear that the captain’s go around decision came far too late. It notes that the bare minimum altitude for a 737 go around is 50 feet, as 30 feet of altitude are lost when executing the manoeuvre. The manoeuvre also demands three seconds to executive effectively.

After the aircraft came to rest in the water, the report shows that the crew handled the evacuation poorly. The first officer initally attempted to evacuate passengers through the right cockpit window. When this proved unviable, he conducted the evacuation through the right-hand service door.
Meanwhile, a flight attendant on the left side of the aircraft was unable to detach a life raft from the aircraft, as her only training for this exercise consisted of watching a video.

The report lists 13 recommendations for five parties including Lion Air, airport operator PT Angkasa Pura I, and the Directorate General of Civil Aviation.
The key recommendations, however, focus on ensuring the pilots employ effective crew resource management skills, hand flying skills, and emergency procedures.

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