A Boeing 737-800 operated by Air Niugini as flight 73 impacted the water of Chuuk Lagoon about 1,500 ft (460 m) short of the runway 04 threshold, during its approach Chuuk International Airport, Micronesia. The aircraft took off from Pohnpei at 22:22 on a flight to Port Moresby in Papua New Guinea via Chuuk. The PIC was the pilot flying for the sector to Chuuk. The copilot was the monitoring pilot. The engineer for the flight was seated in the cockpit jump seat during the approach. Prior to top of descent the crew briefly discussed brake setting for the landing and discussed the approach and landing flap setting. They agreed to select Flap 40. They then discussed the approach and missed approach procedure they would conduct at HAMAX if they found themselves not visual by that point. However, the approach and landing checklist and the briefing on the RNAV approach chart briefings were not conducted in accordance with the SOPs and not using standard phraseology. At top of descent, the PIC stated to the copilot that they were already high and needed to immediately initiate their descent. The crew commenced their descent leaving FL400 at 22:56, at a descent rate of 944 ft/pm. At FL340, the copilot contacted San Francisco radio and reported that they were maintaining FL340. Both pilots discussed the descent clearance for about two minutes, trying to recall and clarify the instructions that they were given. At 23:05, while maintaining FL340, the PIC stated to the copilot that they were high on profile and needed to descend to get back on the required descent profile. At 23:08, the PIC said “alright, we catching back on profile, so just keep the speed up”. The copilot contacted Chuuk radio at 23:08 and requested a weather update. At 23:11, Chuuk radio contacted the crew with the weather update for Chuuk stating: “wind variable at 5, visibility 14 scattered 012 charlie bravo, broken 120 overcast 280, temperature 26 dep point 25, altimeter 2973”. At 23:15, at about 15 nm from Chuuk while passing 8,600 ft, the copilot made an inbound broadcast call stating their intention to track for the RNAV (GPS) runway 04, from the east south-east. Five minutes later the copilot made a general broadcast, stating that they were established on 041 inbound via the RNAV (GPS) runway 04. The aircraft was then configured for the approach. At 1000 feet the aircraft was stable but above the 3 degrees glidepath. At 23:23 the PIC disconnected the auto-pilot and stated: “I’m going back on profile.” When passing 548 ft (602 ft Radio Altitude) on descent, the aircraft entered the storm cell and heavy rain and the PIC called for the wipers to be switched on. After passing the Minimum Descent Altitude (MDA), between 307 ft (364 ft RA) fourteen ‘Sink Rate’ and ‘Glideslope’ aural alerts began to sound. The flight crew disregarded the alerts, and did not acknowledge the “minimums” and 100 ft alerts. After descending through 100 feet the copilot noticed they were dangerously low and called rapidly with high intonation: “Too low! We’re too low! We’re too low! We’re too low!” The aircraft then skipped across the water several times before it settled in the water and turned clockwise through 210 deg and drifted 460 ft (140 m) south east of the runway 04 extended centreline, with the nose of the aircraft pointing about 265 degrees. Local boaters rescued 28 passengers and two cabin crew from the left over-wing exits. Two cabin crew, the two pilots and the engineer were rescued by local boaters from the forward door 1L. One life raft was launched from the left aft over-wing exit by cabin crew CC5 with the assistance of a passenger. The US Navy divers rescued six passengers and four cabin crew and the Load Master from the right aft over-wing exit. All injured passengers were evacuated from the left over-wing exits. One passenger was fatally injured, and local divers located his body in the aircraft three days after the accident. The accident investigators concluded that both pilots were not situationally aware during the approach and did not recognise the developing significant unsafe condition after passing the Missed Approach Point (MAP) when the aircraft entered a storm cell and heavy rain. The weather radar on the PIC’s Navigation Display showed a large red area indicating a storm cell immediately after the MAP, between the MAP and the runway. The copilot as the monitoring pilot was ineffective and was oblivious to the rapidly unfolding unsafe situation. He did not recognise the significant unsafe condition and therefore did not realise the need to challenge the PIC and take control of the aircraft, as required by the Air Niugini SOP. Training records showed that the copilot had been checked in the simulator for EGPWS Alert (Terrain) however there was no evidence of simulator check sessions covering the vital actions and responses required to retrieve a perceived or real situation that might compromise the safe operation of the aircraft. Specifically sustained unstabilised approach below 1,000 ft amsl in IMC as in the case of the accident. The PIC did not conduct the missed approach at the MAP despite the criteria required for visually continuing the approach not being met, including visually acquiring the runway or the PAPI. The PIC did not conduct a go around after passing the MAP and subsequently the MDA although: the aircraft had entered IMC; the approach was unstable; the glideslope indicator on the Primary Flight Display (PFD) was showing a rapid glideslope deviation from a half-dot low to 2-dots high within 9 seconds after passing the MDA; the rate of descent was high (more than 1,000 ft/min) and increasing; there were EGPWS Sink Rate and Glideslope aural alerts; and the EGPWS visual PULL UP warning message was displayed on the PFD. CAUSES [CONTRIBUTING FACTORS]: The flight crew did not comply with Air Niugini Standard Operating Procedures Manual (SOPM) and the approach and pre-landing checklists. The RNAV (GPS) Rwy 04 Approach chart procedure was not adequately briefed. The aircraft’s flight path became unstable with lateral over-controlling commencing shortly after autopilot disconnect at 625 ft (677 ft). From 546 ft (600 ft) the aircraft was flown in Instrument Meteorological Conditions (IMC) and the rate of descent significantly exceeded 1,000 feet/min in Instrument Meteorological Conditions (IMC) from 420 ft (477 ft). The flight crew heard, but disregarded, 13 EGPWS aural alerts (Glideslope and Sink Rate), and flew a 4.5§ average flight path (glideslope). The pilots lost situational awareness and their attention was channelised or fixated on completing the landing. The PIC did not execute the missed approach at the MAP despite: PAPI showing 3 whites just before entering IMC; the unstabilised approach; the glideslope indicator on the PFD showing a rapid glideslope deviation from half-dot low to 2-dots high within 9 seconds after passing the MDA; the excessive rate of descent; the EGPWS aural alerts: and the EGPWS visual PULL UP warning on the PFD. The copilot (support/monitoring pilot) was ineffective and was oblivious to the rapidly unfolding unsafe situation. It is likely that a continuous “WHOOP WHOOP PULL UP” hard aural warning, simultaneously with the visual display of PULL UP on the PFD (desirably a flashing visual display PULL UP on the PFD), could have been effective in alerting the crew of the imminent danger, prompting a pull up and execution of a missed approach, that may have prevented the accident.