A pilot urged Ethiopian Airlines managers for more training on the Boeing 737 Max aircraft in an effort to prevent a crash similar to that of the doomed Lion Air Flight 610 flight that killed all 189 passengers, according to emails and documents seen by Bloomberg News.

The pilot reportedly warned managers in December that more training was required following the Lion Air crash in October. He also called for greater communication with 737 crew members, Bloomberg reported.

Three months after the pilot delivered the warning, Ethiopian Airlines Flight ET302 crashed and killed all 157 passengers.

"It will be a crash for sure," the pilot said in an email in December, Bloomberg reported.

It is unclear if the Ethiopian Airlines crash would have been prevented if the airline heeded the pilot's warnings.

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A pilot urged Ethiopian Airlines senior managers for more training on the Boeing 737 Max aircraft, following the doomed Lion Air Flight 610 crash that killed all 189 passengers two months earlier, according to emails and documents seen by Bloomberg News.

Bernd Kai von Hoesslin, the Ethiopian Airlines pilot and 737 instructor, reportedly warned managers in December that more training was required following the Lion Air crash in October. He also suggested greater communication between crew members. Three months after von Hoesslin delivered the warning, Ethiopian Airlines Flight ET302 crashed and killed all 157 passengers.

Von Hoesslin was concerned with how pilots would handle an issue with the 737 Max's flight-control feature in conjunction with cockpit warnings, according to the emails seen my Bloomberg.

"It will be a crash for sure," von Hoesslin said in an email in December, Bloomberg reported.

Von Hoesslin also expressed his concerns on aircraft maintenance and pilot fatigue in 418-pages of communications. Von Hoesslin reportedly left the airline in April and included his previous advice with his resignation letter. He declined to comment for the Bloomberg story.

Related: Deadly Ethiopian Airlines crash kills all passengers thought to be onboard

20 PHOTOS Deadly Ethiopian Airlines crash kills all passengers thought to be onboard See Gallery Deadly Ethiopian Airlines crash kills all passengers thought to be onboard People walk past a part of the wreckage at the scene of the Ethiopian Airlines Flight ET 302 plane crash, near the town of Bishoftu, southeast of Addis Ababa, Ethiopia March 10, 2019. REUTERS/Tiksa Negeri Family members of the victims involved in a plane crash react at Addis Ababa international airport Sunday, March 10, 2019. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia's capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said, as anxious families rushed to airports in Addis Ababa and the destination, Nairobi. (AP Photo/Mulugeta Ayene) A family member of a victim involved in a plane crash talks on a mobile phone at Addis Ababa international airport Sunday, March 10, 2019. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia's capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said, as anxious families rushed to airports in Addis Ababa and the destination, Nairobi. (AP Photo/Mulugeta Ayene) Family members arrive at Bole International airport in Addis Ababa, Ethiopia, Sunday, March 10, 2019, to check on information on the Ethiopian flight that crashed. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia’s capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said. (AP Photo/Elias Masseret) Un avion des Ethiopian Airlines à destination de Nairobi s'est écrasé dimanche avec 149 passagers et huit membres d'équipage, a annoncé la compagnie. "Il n'y a pas de survivants à bord du vol, qui transportait des passagers de 33 pays", rapporte quant à elle la télévision publique, citant une source proche d'Ethiopian Airlines. /Photo d'archives/REUTERS/Amr Abdallah Dalsh Family members arrive at Bole International airport in Addis Ababa, Ethiopia, Sunday, March 10, 2019, to check on information on the Ethiopian flight that crashed. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia’s capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said. (AP Photo/Elias Masseret) FILE - In this Jan. 25, 2010, file photo, Bole International airport in Addis Ababa, Ethiopia. An Ethiopian Airlines flight with 157 people thought to be on board crashed shortly after takeoff Sunday, March 10, 2019 from Ethiopia's capital headed to Nairobi, the airline said. (AP Photo/Samson Haileyesus-file) Relatives of the victims involved in a plane crash wait for information Jomo Kenyatta International Airport, Nairobi, Kenya, Sunday, March 10, 2019. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia's capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said, as anxious families rushed to airports in Addis Ababa and the destination, Nairobi. (AP Photo/Khalil Senosi) Relatives of the victims involved in a plane crash wait for information at Jomo Kenyatta International Airport, Nairobi, Kenya, Sunday, March 10, 2019. An Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia's capital on Sunday morning, killing all 157 people thought to be on board, the airline and state broadcaster said, as anxious families rushed to airports in Addis Ababa and the destination, Nairobi. (AP Photo/Khalil Senosi) Kenya Airport Authority (KAA) Managing Director and CEO Jonny Andersen and Kenya's Transport Minister James Macharia (L) give a press conference on Ethiopia airline's crash in Ethiopia, at the Jomo Kenyatta International Airport in Nairobi, Kenya, on March 10, 2019. - An Ethiopian Airlines Boeing 737 crashed Sunday morning en route from Addis Ababa to Nairobi with 149 passengers and eight crew believed to be on board, Ethiopian Airlines said. (Photo by Yasuyoshi CHIBA / AFP) (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images) Kenya Airport Authority (KAA) Managing Director and CEO Jonny Andersen speaks during a press conference on Ethiopia airline's crash in Ethiopia, at the Jomo Kenyatta International Airport in Nairobi, Kenya, on March 10, 2019. - An Ethiopian Airlines Boeing 737 crashed Sunday morning en route from Addis Ababa to Nairobi with 149 passengers and eight crew believed to be on board, Ethiopian Airlines said. (Photo by Yasuyoshi CHIBA / AFP) (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images) A Chinese group send messages as informing about their colleagues who were allegedly onboard the plane that crashed in Ethiopia, at the Jomo Kenyatta International Airport in Nairobi, Kenya, on March 10, 2019. - An Ethiopian Airlines Boeing 737 crashed on March 10 morning en route from Addis Ababa to Nairobi with 149 passengers and eight crew believed to be on board, Ethiopian Airlines said. (Photo by Yasuyoshi CHIBA / AFP) (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images) A Chinese group look at the arrival flight schedule as informing about their colleagues who were allegedly onboard the plane that crashed in Ethiopia, at the Jomo Kenyatta International Airport in Nairobi, Kenya, on March 10, 2019. - An Ethiopian Airlines Boeing 737 crashed on March 10 morning en route from Addis Ababa to Nairobi with 149 passengers and eight crew believed to be on board, Ethiopian Airlines said. (Photo by Yasuyoshi CHIBA / AFP) (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images) A woman reacts as she waits for the updated flight information of Ethiopian Airlines Flight ET 302, where her fiance was onboard at the Jomo Kenyatta International Airport (JKIA) in Nairobi, Kenya March 10, 2019. REUTERS/Baz Ratner People use their mobile phones near the flight information board displaying the details of Ethiopian Airlines Flight ET 302, at the Jomo Kenyatta International Airport (JKIA) in Nairobi, Kenya March 10, 2019. REUTERS/Baz Ratner A flight information board displaying the details of Ethiopian Airlines Flight ET 302 is seen at the Jomo Kenyatta International Airport (JKIA) in Nairobi, Kenya March 10, 2019. REUTERS/Baz Ratner A man looks at his phone outside the Ethiopian Airlines offices in downtown Nairobi, Kenya March 10, 2019. REUTERS/Thomas Mukoya A woman walks with her child outside the Ethiopian Airlines offices in downtown Nairobi, Kenya March 10, 2019. REUTERS/Thomas Mukoya BISHOFTU, ETHIOPIA - MARCH 12: Investigators with the U.S. National Transportation and Safety Board (NTSB) look over debris at the crash site of Ethiopian Airlines Flight ET 302 on March 12, 2019 in Bishoftu, Ethiopia.. All 157 passengers and crew perished after the Ethiopian Airlines Boeing 737 Max 8 Flight came down six minutes after taking off from Bole Airport. (Photo by Jemal Countess/Getty Images) People work to search for belongings and debris for forensic analysis at the crash site of the Ethiopian Airlines operated Boeing 737 MAX aircraft in which their relatives perished among the 157 passengers and crew onboard, at Hama Quntushele village, near Bishoftu, in Oromia region, on March 15, 2019. - A French investigation into the March 10 Nairobi-bound Ethiopian Airlines Boeing 737 MAX crash that killed 157 passengers and crew opened on March 15 as US aerospace giant Boeing stopped delivering the top-selling aircraft. (Photo by TONY KARUMBA / AFP) (Photo credit should read TONY KARUMBA/AFP/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

"Some of these concerns were safety-related and well within the duty of the airline to adequately address," von Hoesslin said in his resignation letter, according to Bloomberg.

An Ethiopian Airlines spokesman told Bloomberg they could not comment on the story.

Initial news reports suggest that a faulty reading from a sensor could have played a role in both crashes. The reports indicate that the faulty sensor may have triggered the plane's automated system, which would point the nose downward after takeoff to prevent the plane from stalling.

Von Hoesslin mentioned the aircraft's sensor from the automated safety system — a feature currently being scrutinized by investigators. However, it is unclear if the Ethiopian Airlines crash would have been prevented if the airline heeded his warning, Bloomberg noted.

Boeing has been under intense scrutiny following the crashes. Multiple news reports have revealed problems in the production process, including for the 787 Dreamliner aircraft.

Errors on the production line included debris in airspeed sensors, rags and bolts in planes, and loose cabin seats, The Post and Courier reported earlier in May. Tires with cuts in them, untested gears, and malfunctioning hydraulics systems were also spotted by workers, some of whom were allowed to self-inspect their work.

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