Lionair B738 at Denpasar on Apr 13th 2013, landed short of runway and came to stop in sea

Indonesia's NTSC released their final report concluding the probable causes of the accident were:

- The aircraft flight path became unstable below minimum descends altitude (MDA) with the rate of descend exceeding 1000 feet per minute and this situation was recognized by both pilots.

- The flight crew loss of situational awareness in regards of visual references once the aircraft entered a rain cloud during the final approach below minimum descends altitude (MDA).

- The PIC decision and execution to go-around was conducted at an altitude which was insufficient for the go-around to be executed successfully.

- The pilots of accident aircraft was not provided with timely and accurate weather condition despite the weather around the airport and particularly on final approach to the airport was changing rapidly.

The investigation analysed that there were no issues with the aircraft and all systems operated normally.

With respect to the vertical profile the NTSC analysed that during the descent at about 600 feet AGL there was a wind shift initially increasing the aircraft's airspeed and deviations from the selected flight trajectory. About 20 seconds later, at 486 feet AGL, the autopilot was disconnected and the rate of descent increased to above 1000 fpm, at 30 feet AGL the rate of descent was 1136 fpm, the engines' thrust was set between 41 and 45 percent N1 during final approach and the pitch angle varied between 1.1 degrees nose down to 1.8 degrees nose up, just prior to impact the attitude was 1.6 degrees nose down while according to the FCOM the attitude should be between 0.0 and 0.5 degrees nose up and N1 between 58 and 61%.

With respect to the lateral profile the NTSC stated: "... that the flight from minimum descent altitude (MDA) still following the VOR approach lateral configuration (091°), rather than lining up to the runway lateral orientation (087°). The four degrees difference was never corrected by the flying pilot."

With respect to the flight crew appreciating the external environment the NTSC stated: "At an aircraft altitude of approximately 900 feet AGL, the SIC commented that the runway was not in sight whereas the PIC commented that he could see the approach light and commanded to continue the approach. From the interview, the PIC stated that he saw a flashing light at the beginning of runway 09 which was also observed by the SIC later on. During interview, the Ngurah Rai Tower controller stated that during that period, there was no runway lighting system illuminated other than the Precision Approach and Path Indicator (PAPI) lights."

The NTSC analysed that at about 300 feet AGL the sounds of rain on the windshield were recorded by the cockpit voice recorder, however, there were no sounds of the windshield wipers operating. The NTSC stated: "At about 900 feet, the PIC noticed that there was dark area on the short final meanwhile the flashing light was still visible. Based on this information, the PIC predicted that the dark area was narrow and the runway would be visible after a short time. This was an incorrect assessment of the weather conditions at the time. After the aircraft entered the rain, the runway was not visible until the aircraft impacted the water. The PIC’s expectation that the runway would become visible in the near future did not occur. The PIC may not have been aware of the thunderstorm characteristics, especially the mature state of cumulonimbus. The conditions stated above can be concluded as inadequate situational awareness."

The NTSC analysed with respect to crew resource management: "a series of errors occurred during approach, among other thing such as the absence of callouts, lack of monitoring and crosschecking both lateral and vertical path especially below MDA combined with the additional factor of adverse weather conditions at low altitude, were potentially more dangerous as time to make decision was short and the consequences of these events possibly catastrophic; however these errors were not corrected timely by the flight crew in accordance with operator’s CRM principles in managing threat and error."

The airline performed two immediate safety actions following the accident, 4 additional safety recommendations to the airline, two to the airport, two to meteorological services, one to AirNav Indonesia and five to Indonesia's Directorate of Civil Aviation were issued as result of the investigation.

The theoretic and actually flown vertical profiles (Graphics: NTSC):