(CNN) Missing plane Malaysia Airlines Flight 370 was plunging toward the sea with no one in control when it made its last satellite communication, new analysis reveals.

A report released Wednesday by the Australian Transport Safety Bureau provided the clearest picture yet of the plane's final moments in March 2014.

"Additional analysis (of) the final satellite communications to and from the aircraft is consistent with the aircraft being in a high and increasing rate of descent at that time," the report said.

"Additionally, the wing flap debris analysis reduced the likelihood of end-of-flight scenarios involving flap deployment."

According to end of flight simulations run by the Australian bureau, the plane was spiraling in its final moments, descending at up to 25,000 feet per minute (284 mph).

The Australian Transport Safety Bureau has analyzed the recovered flaperon.

AirlineRatings.com aviation expert Geoffrey Thomas told CNN the report debunked theories that the pilot had been flying the plane when it landed in the sea.

"The really important news in this report is that the flap found in Tanzania was stowed," he said, referring to the flaperon that washed up off the East African country in June.

"Therefore there was no way this airplane was being flown by anyone. It was out of control, ran out of fuel and spiraled into the sea at high speed."

Asked what might have happened, she pointed to "two early hypotheses" -- namely, that a fire on board the plane incapacitated everyone through smoke or fumes, or that a rapid decompression, perhaps because of a breach in a window, led to their deaths hours before the plane ran out of fuel and spiraled downward.

"The wreckage showed that what you would have extended -- the landing flaps -- were not extended in the final moments of the flight, so no one was planning to land the plane on water," said Schiavo, a former US Department of Transportation inspector general.

Investigations into pilot

Information had emerged in recent months that raised questions over the actions of chief pilot Zaharie Ahmad Shah , who was in charge of the plane when it disappeared from radar screens.

The magazine quoted a leaked document from an FBI investigation that showed deleted files had been recovered from Zaharie's home-built flight simulator.

They reportedly revealed he had plotted a course into the deep southern Indian Ocean -- a course that closely matched the final flight MH370 is thought to have taken. Investigators said the simulator files had been created just weeks before the jet disappeared, according to the document.

The confidential document, whose contents were not independently confirmed by CNN, summarized the Malaysian police investigation into Zaharie.

In an email to CNN that same month, Joint Agency Coordination Center spokesman Scott Mashford said, "The MH370 captain's flight simulator showed someone had plotted a course to the southern Indian Ocean." The Australian agency is directing the search for MH370.

Mashford did not elaborate on who may have plotted the route.

In August, Malaysian Transport Minister Datuk Seri Liow Tiong Lai told reporters that Zaharie's personal flight simulator had practiced routes over the Indian Ocean, according to Malaysia's Bernama state news agency.

But the minister added there was no evidence to prove that Zaharie had piloted the aircraft to the southern Indian Ocean, Bernama reported, saying "the simulator was used by the pilot for trial and error in many areas. There are thousands of simulations to many destinations."

Zaharie's sister, Sakinab Shah, told CNN her brother had been made a "scapegoat" and that any claims against him were a "fabrication."

3 pieces of debris found

Shortly after it left Kuala Lumpur, Malaysia, for Beijing on March 8, 2014, MH370 ceased communications and vanished, creating one of the greatest aviation mysteries.

More than 20 items of debris have been brought to the attention of investigators, but only three have been confirmed as from MH370 , including the flaperon mentioned in the new report.

Photos: MH370 debris Malaysia Airlines flight 370 disappeared on March 8, 2014. As of October 2016, authorities have definitively linked three pieces of debris to the plane, while four other pieces are believed to "almost certainly" come from the missing aircraft. A flaperon from a Boeing 777 was found on Reunion Island in the Indian Ocean in July 2015. Authorities later confirmed the debris came from MH370. Hide Caption 1 of 7 Photos: MH370 debris Two pieces of debris were found in Mozambique, in December 2015 and February 2016. The Australian Transport Safety Bureau (ATSB) said both pieces "almost certainly" came from the missing plane. Hide Caption 2 of 7 Photos: MH370 debris An examination of stenciling and other identifiable features were used to link the debris to MH370. Hide Caption 3 of 7 Photos: MH370 debris Two more pieces of debris, found in March 2016, were also deemed to have "almost certainly" come from MH370, according to the ATSB. Hide Caption 4 of 7 Photos: MH370 debris One piece is believed to be from the plane's Rolls Royce engine, while the other matched a Boeing 777 interior closet panel. Hide Caption 5 of 7 Photos: MH370 debris A piece of aircraft debris found in Tanzania in June 2016 and transported to Australia. The country's Infrastructure and Transport minister said it was confirmed as coming from MH370 in September 2016. Hide Caption 6 of 7 Photos: MH370 debris A left outboard flap trailing edge section found on the island of Mauritius in May 2016. In October , it was confirmed as coming from MH370. Hide Caption 7 of 7

So far, 110,000 square kilometers (42,000 square miles) have been covered as part of the underwater search for MH370, with the hunt currently due to conclude at 120,000 square kilometers (46,000 square miles).

"Where they're looking is still the area where everyone agrees that's where the plane is," aviation expert Thomas said, adding there were slight disagreements in opinion.

"(But) we're only talking about small increments -- just variations as to exactly, precisely where it could be."

Australian Transport Minister Darren Chester said at a press conference Wednesday the new report confirmed that search crews had been combing the right area.

"To have not found the aircraft at this stage is frustrating for everyone involved and particularly for the families of the passengers and crew," Chester said.

MH370 search meeting begins in Australia

The report came as officials from Malaysia, China and Australia and experts from the United States and United Kingdom met in Canberra, Australia, to discuss the ongoing search.

"They are reviewing all the available data and associated analysis, assumptions and modeling undertaken to inform the definition of the search area," Australian Transport Safety Bureau communication officer Dan O'Malley told CNN on Wednesday.

Thomas said there had been suggestions the meeting may decide to extend the search for MH370 beyond the current search zone.

"It's an opportunity to gather the experts from around the world to look at the available information, to exchange ideas," Chester said. "It's an opportunity for just a full assessment of how the underwater search is being carried out and a reassessment."

The meeting is due to run until Friday.