On the surface, the discovery on a Reunion Island beach is just what investigators have been waiting for -- the first physical piece of evidence since Malaysia Airlines Flight 370 vanished en route to Beijing in March 2014 with 239 people aboard.
The latest assessment from authorities is a key step, but it's just the first one, said Shawn Pruchnicki, an air safety expert at Ohio State University.
"This is like having a 1,000-piece puzzle," he said, "putting one piece on the table and saying, 'What's the picture?'"
Based on the Malaysian Prime Minister's statement, so far investigators know just one thing, CNN aviation analyst Peter Goelz said.
"It confirms the sad truth that the plane ended up in the water with all its passengers and crew and that there were no survivors, and that's the fundamental truth of today. The confirmation on how it went down is still many months away," he said. "This is a very difficult investigation. It's going to continue to be one."
Here's a look at some key questions during the next steps of the investigation:
What can we learn from the condition of the debris?
French investigators say they'll continue to do tests on the flaperon to determine whether it came from the missing plane.
They'll also be looking to see what it can tell them about what happened to the aircraft.
Images of the debris appear to show a small amount of damage to the front of the flaperon and a ragged horizontal tear across the back.
What could that mean? It depends whom you ask.
One group of independent observers has said the damage to the flaperon gives authorities a good indication that the piece came off while the plane was still in the air.
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, led by American Mobile Satellite Corp. co-founder Mike Exner, wrote in a preliminary assessment.
Others have offered differing opinions.
"It really is not going to tell us too much about the final moments of the aircraft," said Geoffrey Thomas from AirlineRatings.com
However, Tom Ballantyne of Orient Aviation magazine said the condition of debris could indicate if the plane met a catastrophic end. Charring, for example, could indicate an explosion, he said.
Schiavo said investigators would be on the lookout for telltale signs of what caused the crash: "It's possible to find positive evidence of a criminal act, or, of course they could find the absence of that.
"If they find characteristic pitting in the wing structure, in the metal or the composite, that indicates there was some sort of explosive device, or if they find residue, which is not likely (after) this long in he ocean," she said.
"But they'll probably not be able to tell why the plane went down -- only that it did, and the manner in which it did."
To learn more, the flight data recorders -- or so-called black boxes -- would be crucial.
Will the main search area move?
Australian Deputy Prime Minister Warren Truss told reporters last week that the discovery of the debris in Reunion was consistent with models searchers have been using.
"We remain confident that we're searching in the right place," he said.
He said authorities would "continue to concentrate our efforts on seeking to locate the aircraft in the identified area."
The current search is focused deep in the ocean off Western Australia, along an arc considered by investigators to be the most likely area the plane went down if it turned back toward Malaysia, as indicated by data, and stayed in the air before running out of fuel.
Confirmed debris could help investigators focus their search, but it's a complicated process, particularly given how much time has passed since the plane went missing, said David Gallo of the Woods Hole Oceanographic Institution.
"The ocean is a great disperser," he said. "If you put three objects in the ocean of different sizes and shapes, and let them go at the same time from the same place, over time the ocean will separate them, depending on whether they're being pushed by the winds or the currents or a combination of both."
Is it more likely the main section will be found?
Truss said no.
The flaperon find, he said last week, does not "provide a great deal of help in specifically identifying where the aircraft is."
But confirmation that the find is from the missing aircraft likely to give investigators further belief that other pieces of the plane have been carried by currents to the same region.
Could they find more debris soon?
"I'd be surprised if they found more after 515 days. This (the flaperon) was an extraordinary piece of luck. It was miraculous, almost," said Goelz, a former managing director of the U.S. National Transportation Safety Board. "So I'm not optimistic. ... They're searching in the right place. They need to double down on that, and let's hope that they find something in the next six months."
Will debris lead to a rethinking of past theories?
Thomas said, if anything, the location of the potential debris confirms modeling from the University of Western Australia that showed material from the plane could wash up around Reunion between 12 to 24 months after the plane's disappearance.
Despite the modeling, no one had been searching in that area, he said, because of the vast nature of the Indian Ocean and the multitude of factors that meant finding anything would be a matter of luck and time.
"It was a matter of waiting for something to wash up," he said.