Poor crew resource management and an unstable approach contributed to a runway excursion involving a Lion Air Boeing 737-900ER on 20 February 2016.
The aircraft (PK-LFG) was flying from Balikpapan to Surabaya service, says the Indonesia's National Transportation Safety Committee (NTSC) in its final report into the incident.
After an uneventful flight from Balikpapan, the crew was instructed to land on Surabaya Juanda International airport's runway 10, amid thunderstorms in the area.
Passing 600ft on an ILS approach, the pilot-in-command noticed that the second-in-command (SIC), who was pilot flying the approach, was having trouble controlling the aircraft. He assisted the SIC to help adjust the approach profile.
Shortly thereafter, air traffic control notified that visibility had deteriorated to 1000m. There was a subsequent glideslope warning from the ground proximity warning system (GPWS). After the aircraft descended below 100ft, the SIC advised the PIC to "fly left."
There was no voice recording, however, of the PIC verbally informing the SIC that he was taking control of the aircraft for the landing.
"The aircraft landed on runway 10 at approximately 552 meters from the beginning runway with speed 9 knots above the target," says the NTSC. "After touch down, the thrust reverser levers could not be selected as the thrust levers were not in idle position, the spoiler deployment delayed for about 10 seconds and the brake pressure increased 9 seconds after touch down."
Manual brake pressure reached 3000psi 21 seconds after touchdown, as both pilots applied manual braking.
"The combination of prolonged touchdown, delay in spoiler deployment, thrust levers not at idle position, and late of brake application likely affected the landing distance required," says the NTSC.
Minutes after landing, cockpit voice recorder data captured the pilot expressing regret that he had not conducted a go around.
"While the aircraft on short approach, the PIC was concerned about the deteriorating weather and noticed that the SIC had difficulty to control the aircraft," says the NTSC. "However, the PIC did not show a firm decision by implementing the procedure, resulted in the improper task distribution of pilot flying and pilot monitoring. The improper task distribution indicated the lack of leadership."
The PIC was 59 years old with 28,000 hours experience, of which 4,218 hours were on the 737. The SIC was 35 years old, with 1,817 hours of total experience, of which 1,617 hours were on the 737.
As a result of the incident, the NTSC recommended that Lion review its pilot training to improve decision making, and improve manual flying skills. In addition, the NTSC called on other Indonesian carriers to emphasise improved pilot decision making, and provide more training around the use of speed brakes, thrust reversers, and autobrakes.