Indonesia’s National Transportation Safety Committee (NTSC) has issued three “immediate” safety recommendations to low-fare carrier Lion Air as it continues to investigate the April 13 crash of a Boeing 737-800 in the water just short of Runway 09 at the Ngurah Rai International Airport in Bali.

The aircraft was destroyed when it touched down short of the runway following a non-precision VOR/DME instrument approach. The 737 came to a stop 66 ft. from the shore and approximately 1,000 ft. from the Runway 09 threshold. 

None of the 101 passengers and seven crewmembers were killed.

In a preliminary report issued May 14, the NTSC called on Lion Air to “emphasize to pilots” the importance of complying with minimum descent criteria for instrument approaches, and to ensure pilots are trained on transferring control of the aircraft “at critical altitudes or critical times” and are aware of the risks of doing so.

In its factual findings, the NTSC says that the aircraft was airworthy and the approach to Bali from Bandung was normal, with the second-in-command pilot—having 1,200 flight hours in total and 923 hr. in the 737—in the role as “pilot-flying.” The pilot-in-command had 15,000 hr. in total, and 7,000 hr. in the 737.

The VOR/DME approach provides lateral guidance to a point approximately 1.5 naut. mi. from the threshold at an altitude of 454 ft. above ground level (AGL), also known as the “missed approach point” (MAP), after which the crew is required to have visual contact with the runway environment (the runway itself or the runway lights) to continue descending.

If pilots do not have visual contact with the runway at the MAP or at any time below the MAP, procedures typically call for the approach to be aborted immediately.

According to video cameras and other aircraft on the ground, rain was falling at the approach end of the airport at the time of the accident, and another plane waiting to take off could not see the Lion Air aircraft at 3 naut. mi. from the threshold, where its altitude would have been about 1,000 ft. The tower reported the wind to be blowing from 120 deg. at 5 kt., representing a slight headwind and right crosswind.

Based on flight data recorder and cockpit voice recorder information, the NTSC says the second-in-command pilot stated at approximately 900 ft. AGL that he did not see the runway, but there is no mention of whether either pilot had the required visual sighting at the minimum descent altitude (MDA) of 454 ft. AGL.

From the flight data recorder however, the NTSC notes that “upon reaching the MDA the flight profile indicated a constant path,” suggesting that one or both pilots presumably had the runway in sight.

The approach continued, with the second-in-command pilot flying until 150 ft. AGL when the pilot-in-command (PIC) “took over the controls” according to the NTSC. “The [second-in-command] handed the controls to the PIC and stated that he could not see the runway,” the preliminary report states.

The PIC continued flying the approach until the aircraft was at 20 ft. AGL, at which point he called for a go-around. The aircraft impacted the water one second later.