JAKARTA: As the seconds ticked by on the doomed Indonesian flight, the pilot handed the controls to his co-pilot and flipped through the pages of a technical manual, trying to figure out what was happening.
Then, as the nose of Lion Air Flight 610 repeatedly bucked downward, Harvino, the co-pilot, began to pray.
The supplication was caught on the final seconds of audio in the cockpit voice recorder.
“God is great,” Mr. Harvino, an experienced Indonesian aviator, said, then recited a verse asking God to grant a miracle.
But there was no miracle on Oct. 29, when the brand-new Boeing 737 Max 8 dived into the Java Sea in Indonesia, amid good weather, after 12 minutes in the air.
“I think he knew it was unrecoverable,” said Nurcahyo Utomo, the head of the air accident subcommittee of the Indonesian National Transportation Safety Committee, who listened to and described the contents of the cockpit voice recorder that was retrieved from the ocean floor in January.
Until that point, he said, the pilots had sounded in control and calm.
With the crash of a second nearly brand-new Boeing 737 Max 8 earlier this month, when Ethiopian Airlines Flight 302 slammed into the ground near the capital, Addis Ababa, there has been a renewed focus on the investigation into what caused Flight 610 to crash in Indonesia, killing all 189 people on board.
Indonesian transportation officials say they do not expect to publish a final report on the accident until July or August at the earliest. A preliminary report, based on the contents of the flight data recorder — one of the two so-called black boxes that give investigators clues to what happened in aviation accidents — was released in November.
The cockpit voice recorder was not found until after the preliminary report was released, so the conversations between Bhavye Suneja, an Indian national who was piloting the plane, and Mr. Harvino were not included in the initial investigative account.
The report noted that the plane’s nose suddenly shifted downward more than 20 times, a motion that investigators think may have been caused by the incorrect triggering of a new automated anti-stall system on the Boeing Max model.
Since the Lion Air crash, pilots certified to fly the Max have complained that they were not briefed on the new system or on how to counter it should incorrect data force the nose down.
Indonesian aviation regulations prohibit a transcript of the cockpit voice recorder from being made public. But investigators from the National Transportation Safety Committee who listened to the recording described the sounds emanating from the cockpit as the flight crew fought to take control of a plane that seemed almost magnetically propelled toward earth.
Throughout the brief flight, an ominous rattle could be heard on the voice recorder, evidence that a device called a stick shaker was clattering to alert the pilots of a potential stall that could lead to a crash, said Ony Soerjo Wibowo, an air safety investigator. A stall can occur when a plane ascends too sharply.
But investigators have speculated that incorrect data — including a 20-degree differential between two sensors designed to measure, essentially, the difference between the pitch of the plane and direction it is moving through the air — could have mistakenly triggered both the stick shaker and the anti-stall system, which is called MCAS.
The plane had recorded days of questionable data related to air speed, altitude and the angle of the plane’s climb.
In the first sign of trouble on Oct. 29, the plane dipped around 700 feet, and in the subsequent minutes, MCAS appears to have kept dragging the plane’s nose down, prompting the pilots to try to push the plane back up by using switches that control stabilizers on the tail.
The flight crew radioed back to the air traffic control tower in Jakarta, the Indonesian capital, to request permission to return to the airport, which was granted. The pilot also asked for the plane to be given a 3,000-foot clearance above and below as it continued to roller coaster through the air.
Flight 610 never turned back to the airport.
In the cockpit voice recording, the pilots discussed unreliable airspeed and altitude readings they were getting, national transportation safety officials said.
They consulted the manual to deal with these anomalies. But they did not seem to know about the MCAS system, nor did they speak about what was causing the plane to repeatedly push downward.
Shortly after Mr. Harvino’s prayer, the plane disappeared from radar, and the cockpit voice recorder stopped. The plane plummeted 5,000 feet, crashing into the Java Sea with such force that parts of the fuselage turned into powder.
Mr. Harvino’s remains are missing to this day.