The debris -- which investigators seem increasingly confident came from a Boeing 777 -- was discovered this week on the remote Indian Ocean island of Reunion.
Work to conclusively identify the debris will begin midweek, French prosecutors say, but not before a French investigative judge meets with French and Malaysian air transport investigators and Malaysian judicial authorities.
Boeing said it is sending experts to France. The U.S. National Transportation Safety Board also will travel to take part in the probe, a source with knowledge of the investigation told CNN.
A preliminary report could come as early as next week, a source close to the French investigation told CNN. The report won't give "an exact sequence of events," the source said, but will at least eliminate some scenarios.
Meanwhile, anguished friends and relatives of MH370 passengers, who had clung to the thin hope that perhaps their loved ones would some day be found alive, are coming to grips with the growing realization that's not likely to happen.
"What kept me going until now was repeatedly imaging the moment I would reunite with my daughter," said Beijing resident Zhang Meiling, whose only child was aboard the flight.
If confirmed, the piece of wreckage would be the first bit of physical evidence recovered from MH370. It could help resolve some questions about the fate of the aircraft, but many others remain unanswered.
Here's where things stand:
The part turned up this week on the shore of Reunion, an island in the western Indian Ocean, more than 2,000 miles from the search zone.
"I thought perhaps it's from a plane crash so I said don't touch it anymore," said Johnny Begue, who was the first to spot the debris. "Because if it's a plane crash, then people have died and you have to [have] respect for them."
To experts, it looks a lot like a flaperon, part of an aircraft's wing that helps control its roll and speed.
Boeing investigators said they are confident the debris is from a 777 aircraft, according to a source close to the investigation.
The source said Boeing investigators are basing their view on photos that have been analyzed and a stenciled number that corresponds to a 777 component.
Another source told CNN that Boeing engineers have seen a part number -- 10-60754-1133 -- in photos of the component. A Boeing parts supplier confirmed the number was on a seal associated with the Boeing 777, the source said.
Images of the debris appear to match schematic drawings for the right-wing flaperon from a 777.
Malaysia's deputy minister of transport, Abdul Aziz Kaprawi, also weighed in, saying the part "most certainly belongs to a Boeing 777," but he didn't draw any more direct connection between the part and the missing flight. A French aeronautics investigator familiar with the ongoing investigation agreed.
Martin Dolan, the head of the Australian agency coordinating the underwater search for the plane, told CNN he is "increasingly confident but not yet certain" that the debris is from MH370.
But, he said, "the only 777 aircraft that we're aware of in the Indian Ocean that could have led to this part floating is MH370."
New debris, which washed ashore Thursday and appears to resemble remnants of a suitcase, is also part of the investigation, Reunion Island police officials confirmed to CNN. That debris will be taken to be analyzed at a police lab in Pontoise, outside the French capital, the Paris prosecutor's office said in a statement Friday. The prosecutor's office did not provide any timing for the analysis.
But Australian Deputy Prime Minister Warren Truss said officials were less sure that "the bag has anything to do with MH370" than they are about the plane component.
Teams in Reunion have continued to search the stretch of coast where the debris was found.
The debris was placed in a crate for the trip to France, where it will be taken to a lab operated by the French General Directorate of Armament. That agency has sophisticated equipment and expertise to quickly identify the plane the debris belongs to and what happened to it, a source close to the French investigation told CNN.
That analysis will begin on Wednesday, the Paris prosecutor's office said in a statement.
Malaysia, which is responsible for the overall investigation into MH370's disappearance, is sending teams of aviation officials to Toulouse, where investigators will analyze it, and Reunion, the country's Prime Minister said Thursday.
It's unclear when the identification process will be completed and its results announced.
"I understand that the photographs that are available are of such detail that it may be possible to make an identification without further physical examination," Truss said Friday.
The photographs have enabled aviation experts to weigh in one of the biggest aviation mysteries of recent years.
One group of independent observers
said that the damage to the flaperon should give authorities a good indication that the piece came off while the plane was still in the air.
The group, led by American Mobile Satellite Corp. co-founder Mike Exner, points to the small amount of damage to the front of the flaperon and the ragged horizontal tear across the back.
The rear damage could have been caused if the airliner had its flaperon down as it went into the ocean, some members of Exner's group wrote in a preliminary assessment after looking at photos and videos of the component.
But the lack of damage to the front makes it more likely the plane was in a high-speed, steep, spiral descent and the part fluttered until it broke off, the group said.
But an aircraft component specialist who spoke to CNN disagreed.
The lack of damage to the front section "tells me that the component could still have likely been back in its original position inside the wing itself," said Michael Kenney, senior vice president of Universal Asset Management, which provides plane components to airlines.
Authorities have so far been unable to establish why Flight 370 flew sharply off its route from Kuala Lumpur, Malaysia, to Beijing and disappeared on March 8, 2014.
A preliminary assessment by U.S. intelligence agencies
, produced in the wake of the MH370 disaster, suggested it was likely someone in the cockpit deliberately caused the aircraft's movements before the Malaysian airliner disappeared.
Two U.S. officials briefed on the matter told CNN that the assessment, which was not intended for public release, was prepared months ago and was solely based on available satellite and other evidence.
The U.S. intelligence assessment
was largely focused on the multiple course changes the aircraft made after it deviated from its scheduled Kuala Lumpur-to-Beijing route. Analysts determined that, absent any other evidence, it's most likely someone in the cockpit deliberately moved the aircraft to specific waypoints, crossing Indonesian territory and eventually toward the south Indian Ocean.
Malaysian investigators haven't reported finding any evidence that casts suspicion on the pilots.
The airliner's crew has been the focus of attention since the mysterious disappearance, but no proof has emerged indicating they intended to destroy the plane
. Law enforcement and intelligence agencies from numerous countries examined the plane's manifest of crew and passengers and found no significant information to suggest anyone on board posed an obvious threat.
Confirming that the part is from MH370 would establish "really beyond any doubt" that Flight 370 ended its journey in the Indian Ocean, Australia's Truss said.
It would also bolster Australian officials' confidence that they are searching for the rest of the plane's wreckage in roughly the right place, he said, as models of ocean currents make it credible that some debris would drift to the region around Reunion.
But the wreckage is unlikely to help with the underwater search for the remains of the plane, which is taking place in a remote part of the southern Indian Ocean, far off the western coast of Australia.
"I don't think it contributes a great deal to our knowledge of where the aircraft is located," Truss said, noting the length of time since it entered the water and "the vagaries of the currents."
Investigators need to find Flight 370's flight recorders to have any hope of gleaning a better understanding of what happened on board the plane.
And relatives want to know what became of their loved ones.
"We admit, we still do hope that one day they'll come back," said Maira Elizabeth Nari, the 18-year-old daughter of Andrew Nari, the chief steward on the plane. "But if they're not, then it's OK. We'll accept whatever it is, though many of us are in denial."
"No matter where the debris is found, we care more about the whereabouts of our family members," the statement from the Chinese families said.