Four years ago, Malaysia Airlines MH370, along with 239 people on board, was missing, and a 1500-page report revealed why the plane has not been found.
Independent investigators released the document on Monday, but the uncertain report did not comfort families who had been waiting for four years.
Although there is little comfort for friends and families of the missing passengers, the report does explain why the 200 million yuan search failed.
According to regulations at the time, the Boeing 777-200 was equipped with four emergency positioning transmitters, (ELTs), but none worked.
The report said there were reports that if the plane entered the water, it would be difficult to transmit signals.
"in these cases, due to flooding, the ELT is not activated, or the transfer is invalid. This is a serious hindrance to any search and rescue efforts and may mean that the location of the aircraft has not been found for a considerable period of time. "
All four ELT batteries are within their expiration date, the report said. But it is common for ELT to fail to work, the report said, "of the 173 aircraft accidents involving ELTs, only 39 recorded ELT being effectively activated."
The chief investigator told reporters on Monday that his team was unable to determine what had happened on the plane, even if debris had been washed up on the east coast of Africa.
He said they did not believe the pilot was behind the shift to the Indian Ocean, which must be carried out under manual control and that "illegal interference by third parties" could not be ruled out.
Although they have been searching the sea floor for four years, the families have been destroyed because of a lack of comfort information or new developments.
Danika Weeks of Paul Weeks, an Australian missing person, says the search needs to continue.
They can't just cover it up and say, "that's it," she said.
"they need to keep searching.-that's for sure."
Malaysia's government insisted the report was not "final" because the plane had not yet been found. Officials said they would continue the search if new credible information about the aircraft's location surfaced.