KUALA LUMPUR, Malaysia (AP) -- Air traffic controllers did not realize that Malaysia Airlines Flight 370 was missing until 17 minutes after it disappeared from civilian radar, according to a preliminary report on the plane's disappearance released Thursday by Malaysia's government.
The government also released other information from the investigation into the flight, including audio recordings of conversations between the cockpit and air traffic control, the plane's cargo manifest and its seating plan.
It provided a map showing the Boeing 777's deduced flight path and a document detailing actions taken by authorities during the hours of confusion that followed the jet's disappearance near the border between Malaysian and Vietnamese airspace. Many of the details have previously been disclosed.
The report noted that there is no requirement for real-time tracking of commercial aircraft, and said the uncertainty about Flight 370's last position made it much more difficult to locate the plane. It recommended that international aviation authorities examine the safety benefits of introducing a tracking standard.
The plane went off Malaysian radar at 1:21 a.m. on March 8, and Vietnamese air traffic controllers began contacting Kuala Lumpur at 1:38 a.m. after they failed to establish verbal contact with the pilots and the plane didn't show up on their radar, according to the five-page report, which was dated April 9 and sent last month to the International Civil Aviation Organization.
The documents showed that Malaysian authorities did not launch an official search and rescue operation until four hours later, at 5:30 a.m., after efforts to locate the plane failed.
They indicated that Malaysia Airlines at one point thought the plane may have entered Cambodian airspace. The airline said in the report that "MH370 was able to exchange signals with the flight and flying in Cambodian airspace," but that Cambodian authorities said they had no information or contact with Flight 370. It was unclear which flight it was referring to that supposedly exchanged signals with MH370.
Malaysian Prime Minister Najib Razak last week appointed a team of experts to review all the information the government has regarding the missing plane, and decide which information should be made public.
"The prime minister set, as a guiding principle, the rule that as long as the release of a particular piece of information does not hamper the investigation or the search operation, in the interests of openness and transparency, the information should be made public," Defense Minister Hishammuddin Hussein said in a statement Thursday.
Hishammuddin said authorities reviewed data from Malaysian military radar hours after the plane vanished from civilian radar, and only discovered then that it had tracked the jet making a turn-back in a westerly direction across Peninsular Malaysia.
He said he was informed about the military discovery two hours later and relayed this to Najib, who immediately ordered a search in the Strait of Malacca. He defended the military's inaction in pursuing the plane for identification.
"The aircraft was categorized as friendly by the radar operator and therefore no further action was taken at the time," Hishammuddin said.
The cargo manifest includes a receipt for a package containing lithium ion batteries, noting that the package "must be handled with care." Some questions had been raised in March about the batteries, but Malaysia Airlines said then that they were in compliance with the International Civil Aviation Organization and the International Air Transport Association requirements and classified as "non-dangerous goods."
Meanwhile, Malaysia Airlines on Thursday told relatives of passengers who were aboard Flight 370 to move out of hotels and return home to wait for news on the search for the plane.
Since the jet disappeared, the airline has been putting the relatives up in hotels, where they've been briefed on the search. But the airline said in a statement that it would close its family assistance centers around the world by May 7, and that the families should receive search updates from "the comfort of their own homes."
The airline said it would establish family support centers in Kuala Lumpur and Beijing, and would keep in close touch with the relatives through phone calls and meetings.
Malaysia Airlines also said it would pay advance compensation to the relatives.
The plane vanished during a flight from Kuala Lumpur to Beijing, and most of the 227 passengers were Chinese.
No wreckage from the plane has been found, and an aerial search for surface debris ended Monday after six weeks of fruitless hunting. An unmanned sub is continuing to search underwater in an area of the southern Indian Ocean where sounds consistent with a plane's black box were detected in early April. Additional equipment is expected to be brought in within the next few weeks to scour an expanded underwater area.
The head of the search effort has predicted that the search could drag on for as long as a year.