More than 16 days after it seemingly disappeared without a trace, finally we have a breakthrough in the mystery of missing Malaysia Airlines flight MH370.
Using the latest satellite technology from UK firm Inmarsat, it has now been concluded the plane crashed somewhere in the southern Indian Ocean, west of Perth in Australia.
Families of the 227 passengers and 12 crew now have to accept that all hope of finding their loved ones alive has been lost.
Their devastation will no doubt be immeasurable.
But what might make it harder, is that this conclusion doesn’t bring us any closer to finding out what happened to cause the crash.
How did a passenger jet disappear from all communication channels and fly thousands of miles off course before crashing into a remote part of the ocean without anyone realising?
Here we look at the five key questions that still need to be answered:
1. How do we know the plane crashed when we haven’t found any confirmed debris?
Often investigators know where a plane crashed, even though they cannot immediately find debris.
It may take several years before the key parts of the plane is discovered – including the crucial black box.
The new calculations from Inmarsat have pinpointed the last-known location of the plane to an area of the southern Indian Ocean.
The sea around those parts is up to 13,000ft (almost 2.5miles) deep and currents are likely to have caused wreckage to drift a long way from the original crash site in the past two weeks.
On the plus side, even one single piece of plane debris may be enough for investigators to determine whether the plane exploded or crashed, for example.
2. Will the black box ever be found?
The most important piece of evidence to find is flight MH370’s black box.
The piece of equipment – which is in fact usually orange – is around 12 inches long and designed to survive virtually any impact.
It records all the data from the plane and without it, we might never know what happened.
But search teams are now racing against time to find it, as the locator beacon battery will only last around 30 days.
Of course, it may be possible to find it without that locator, but it could potentially be much harder.
When Air France flight 447 disappeared near Brazil, it was a further two years after the first wreckage was found before the black box was recovered.
3. Why did none of the passengers communicate before the plane crashed?
Angry family members will be wondering why it has taken so long to find out where the plane ended up.
How did a plane disappear from all communication channels and fly around seven hours in the opposite direction and no one realised?
If passengers had known they were in trouble, surely they would have tried to make calls or send texts?
Experts have said that flying above 10,000ft and at such speed means no one on board would get a phone signal.
But others report have suggested the plane could have been as low as 5,000ft at one stage.
Is it possible the passengers didn’t realise they were in trouble?
One of the more dramatic theories is that if intervention by the pilot is blamed for this crash, he could of knocked out the rest of the plane by de-pressurising the cabin while he wore an oxygen mask.
4. How did no one notice the plane had gone so far off course?
Even if all the passengers were either incapacitated, or unaware something was wrong, how did the plane avoid detection by other radars?
Last week, investigators said MH370’s last-known location was to the west of Malaysia.
It could then have flown thousands of miles along a ‘northern corridor’ or a ‘southern corridor’ based on estimates of how much fuel it had in the tank.
The southern route always seemed to be regarded as the more likely.
The vast majority of resources on the sea and air were diverted there.
One of the reasons to discount the northern route was that it appeared highly unlikely the plane could have flown over so many countries without being detected.
It would have meant travelling over some of the most heavily guarded countries in the world India, China and Pakistan.
But nevertheless, what about the air space from Malaysia towards the southern Indian Ocean?
Surely this cannot be entirely devoid of radar detection?
5. Were the captain and/or his co-pilot involved?
One of the other few conclusions we have from the Malaysian government, is that they believe the change in flight path was down to “deliberate action” by someone on the plane.
MH370 changed course at least twice from its scheduled route – first to fly west back towards Malaysia and then north west into one of two air lanes used by commercial planes.
Malaysian PM Razak said on March 15: “We can say with a high degree of certainty that the aircraft communications addressing and reporting system was disabled just before it reached the east coast of peninsular Malaysia.
“Shortly afterwards the aircraft’s transponder was switched off.
“From this point onwards, the Royal Malaysian Air Force primary radar showed an aircraft believed to be MH370 did indeed turn back. It then flew in a westerly direction back over peninsular Malaysia before turning north west.
“These movements are consistent with deliberate action by someone on the plane.”
Attention must return to the prospect of a hijacking by Captain Zaharie Ahmed Shah his co-pilot Fariq Hamid or someone else on the plane.
It emerged today that Shah’s wife Faizah Khan will be interrogated by the FBI.
The fact that all communications were turned off, and the distance the plane travelled, points to someone with piloting experience having been involved.
If it wasn’t one of the pilots, was it someone else?
Investigators say terrorism or a mechanical malfunction such as a fire have note been ruled out.
In the first instance, today’s conclusions are devastating for the hundreds of relatives and friends of those who perished.
But an explanation of what happened on board MH370 feels as far away as ever.