Boeing jet crashed in Indonesia after key sensor replaced

JAKARTA, Indonesia (AP) — A crucial sensor that is the subject of a Boeing Co. safety bulletin was replaced on a Lion Air jet the day before it plunged into the Java Sea and possibly worsened other problems with the plane, Indonesian investigators said Wednesday.

Indonesia's National Transportation Safety Committee said it had agreed with Boeing on procedures that the airplane manufacturer should distribute globally on how flight crews can deal with "angle of attack" sensor problems following the Oct. 29 crash that killed all 189 people on board.

The sensor keeps track of the angle of the aircraft nose relative to oncoming air to prevent the plane from stalling and diving.

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JAKARTA, INDONESIA - OCTOBER 29: Search and rescue workers move the remains of a victim of the Lion Air flight JT 610 into a waiting ambulance at the Tanjung Priok port on October 29, 2018 in Jakarta, Indonesia. Lion Air Flight JT 610 crashed shortly after take-off with no sign so far of survivors among the 189 people on board the plane. (Photo by Ed Wray/Getty Images)
Debris from the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ADEK BERRY / AFP) (Photo credit should read ADEK BERRY/AFP/Getty Images)
A relative of passengers prays as she and others wait for news on a Lion Air plane that crashed off Java Island at Depati Amir Airport in Pangkal Pinang, Indonesia Monday, Oct. 29, 2018. Indonesia disaster agency says that the Lion Air Boeing 737-800 plane crashed into sea shortly after it left Indonesia's capital Monday morning. (AP Photo/Hadi Sutrisno)
Members of Indonesian National Search and Rescue Agency (BASARNAS) carry body bags containing the remains recovered from the area where a Lion Air passenger jet is suspected to crash, at Tanjung Priok Port in Jakarta, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
A member of Indonesian Search and Rescue Agency (BASARNAS) inspects debris believed to be from Lion Air passenger jet that crashed off Java Island at Tanjung Priok Port in Jakarta, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
Rescuers search for victims of a Lion Air passenger jet that crashed in the waters off Tanjung Karawang, Indonesia Monday, Oct. 29, 2018. The Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Achmad Ibrahim)
Members of Indonesian Search and Rescue Agency (BASARNAS) inspect debris recovered from near the waters where a Lion Air passenger jet is suspected to crash, at Tanjung Priok Port in Jakarta, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
Customers sit near a Lion Air counter at Soekarno-Hatta International Airport in Tangerang, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and the U.S. (AP Photo/Tatan Syuflana)
Relatives of passengers arrive at Lion Air's crisis center at Soekarno-Hatta International Airport in Tangerang, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and the U.S. (AP Photo/Tatan Syuflana)
A man takes photo of the list of passengers of Lion Air flight JT610 at Soekarno-Hatta International Airport in Tangerang, Indonesia Monday, Oct. 29, 2018. The Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
A relative of passengers weeps as she arrives at Lion Air's crisis center at Soekarno-Hatta International Airport in Tangerang, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
A relative of passengers arrive at Lion Air's crisis center at Soekarno-Hatta International Airport in Tangerang, Indonesia Monday, Oct. 29, 2018. A Lion Air flight crashed into the sea just minutes after taking off from Indonesia's capital on Monday in a blow to the country's aviation safety record after the lifting of bans on its airlines by the European Union and U.S. (AP Photo/Tatan Syuflana)
Relatives comfort each other at the crisis center at Soekarno-Hatta International Airport in Cengkareng, Jakarta, Indonesia, on Monday, Oct. 29, 2018. A Boeing Co. 737 Max jet, operated by Indonesia's Lion Air, crashed in the Java Sea with 189 people on board, making it the model's first accident and potentially the worst commercial aviation disaster in three years. Photographer: Rony Zakaria/Bloomberg via Getty Images
Search and rescue team members look at debris recovered from the crash site on the dockside at Tanjung Priok Port in Jakarta, Indonesia, on Monday, Oct. 29, 2018. A Boeing Co. 737 Max jet, operated by Indonesia's Lion Air, crashed in the Java Sea with 189 people on board, making it the model's first accident and potentially the worst commercial aviation disaster in three years. Photographer: Rony Zakaria/Bloomberg via Getty Images
Search and rescue team members carry a body recovered from the crash on the dockside at Tanjung Priok Port in Jakarta, Indonesia, on Monday, Oct. 29, 2018. A Boeing Co. 737 Max jet, operated by Indonesia's Lion Air, crashed in the Java Sea with 189 people on board, making it the model's first accident and potentially the worst commercial aviation disaster in three years. Photographer: Rony Zakaria/Bloomberg via Getty Images
Debris recovered from the crash site sits on the dockside at Tanjung Priok Port in Jakarta, Indonesia, on Monday, Oct. 29, 2018. A Boeing Co. 737 Max jet, operated by Indonesia's Lion Air, crashed in the Java Sea with 189 people on board, making it the model's first accident and potentially the worst commercial aviation disaster in three years. Photographer: Rony Zakaria/Bloomberg via Getty Images
An undergarment believed to belong to a passenger on board the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ADEK BERRY / AFP) (Photo credit should read ADEK BERRY/AFP/Getty Images)
An Indonesian boatman takes pictures as debris from the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ADEK BERRY / AFP) (Photo credit should read ADEK BERRY/AFP/Getty Images)
A boat sails in the background as debris from the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ADEK BERRY / AFP) (Photo credit should read ADEK BERRY/AFP/Getty Images)
A shoe believed to belong to a passenger on board the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ADEK BERRY / AFP) (Photo credit should read ADEK BERRY/AFP/Getty Images)
Rescue personnel transfer a bag containing human remains into an ambulance at port in Tanjung Priok, North Jakarta, on October 29, 2018, after being recovered at sea following the crash of Lion Air flight JT 610. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by RESMI MALAU / AFP) (Photo credit should read RESMI MALAU/AFP/Getty Images)
JAKARTA, INDONESIA - OCTOBER 29 : Members of a rescue team bring personal items and wreckage ashore at the port in Tanjung Priok, North Jakarta, Indonesia on October 29, 2018, after they were recovered from the sea where Lion Air flight JT 610 crashed off the north coast earlier in the day. - A brand new Indonesian Lion Air plane carrying 189 passengers and crew crashed into the sea on October 29, officials said, moments after it had asked to be allowed to return to Jakarta. (Photo credit should read Jepayona Delita / Barcroft Media via Getty Images)
JAKARTA, INDONESIA - OCTOBER 29 : Members of a rescue team bring personal items and wreckage ashore at the port in Tanjung Priok, North Jakarta, Indonesia on October 29, 2018, after they were recovered from the sea where Lion Air flight JT 610 crashed off the north coast earlier in the day. - A brand new Indonesian Lion Air plane carrying 189 passengers and crew crashed into the sea on October 29, officials said, moments after it had asked to be allowed to return to Jakarta. (Photo credit should read Jepayona Delita / Barcroft Media via Getty Images)
A wallet belonging to a passenger of the ill-fated Lion Air flight JT 610 floats at sea in the waters north of Karawang, West Java province, on October 29, 2018. - All 189 passengers and crew aboard a crashed Indonesian Lion Air jet were 'likely' killed in the accident, the search and rescue agency said on October 29, as it announced it had found human remains. (Photo by ARIF ARIADI / AFP) (Photo credit should read ARIF ARIADI/AFP/Getty Images)
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But a Boeing statement said a safety bulletin, sent to airlines on Tuesday, directs flight crews to existing guidelines on how they should respond to erroneous "angle of attack" data. It wasn't immediately clear if it plans an update, though comments from Indonesian officials indicate they expect one.

Soerjanto Tjahjono, chairman of the transport safety committee, said Wednesday that airspeed indicator malfunctions on the jet's last four flights, which were revealed by an analysis of the flight data recorder, were intertwined with the sensor issue.

"The point is that after the AOA (sensor) is replaced the problem is not solved but the problem might even increase. Is this fatal? NTSC wants to explore this," he said.

Lion Air's first two attempts to address the airspeed indicator problem didn't work and for the Boeing 737 MAX 8 plane's second to last flight on Oct. 28, the angle of attack sensors were replaced, Tjahjono said.

On that flight, from Bali to Jakarta, the pilot's and copilot's sensors disagreed. The 2-month-old plane went into a sudden dive minutes after takeoff, which the pilots were able to recover from. They decided to fly on to Jakarta at a lower than normal altitude.

Indonesian investigators said their flight procedure recommendations to Boeing were based on how the flight crew responded to problems on the Bali to Jakarta flight.

"The draft of what will be conveyed by Boeing this morning has been presented to us," said air accident investigator Nurcahyo Utomo.

"There are some things that we ask for explanation and some that we ask to be removed, and there has been an agreement between NTSC and Boeing to release a new procedure to all Boeing 737 MAX users in the world," he said.

Indonesia's search and rescue agency on Wednesday extended the search effort for a second time, saying it will continue until Sunday. Body parts are still being recovered and searchers continue to hunt for the cockpit voice recorder.

The plane hit the water at very high speed just 13 minutes after takeoff from Jakarta. Its flight crew had requested permission to return to the airport several minutes after taking off.

The Lion Air crash is the worst airline disaster in Indonesia since 1997, when 234 people died on a Garuda flight near Medan. In December 2014, an AirAsia flight from Surabaya to Singapore plunged into the sea, killing all 162 on board.

Lion Air is one of Indonesia's youngest airlines but has grown rapidly, flying to dozens of domestic and international destinations. It has been expanding aggressively in Southeast Asia, a fast-growing region of more than 600 million people.

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