The worst aviation disaster in more than a decade has shocked the world.
Air India officials have confirmed the crash killed at least 241 people and left scores more injured.
Significant questions remain about how a Boeing aircraft with an excellent safety record could crash so soon after take-off.
Here's what we know about what happened and what might have caused the disaster.
What happened to Air India flight AI171 at take-off?
The Boeing 787-8 Dreamliner took off from Ahmedabad Airport in western India bound for London's Gatwick Airport at 1:38pm local time (6:38pm AEST) on Thursday.
Almost immediately after take-off, it sent a mayday call to local aviation authorities.
After indicating the plane faced an emergency, the pilots did not respond to calls from air traffic control.
Publicly available information on the Flightradar24 website shows that the plane reached a height of 625 feet (190m) before starting to come down.
Faiz Ahmed Kidwai, the director general of the directorate of civil aviation, told AP that the crash occurred five minutes after departure.
Video circulating online shows the aircraft dropping, before a massive fireball erupts over the skyline, with plumes of black smoke rising high over the area.
The plane crashed in a densely populated area of the city, hitting the BJ Medical College hostel.
Divyansh Singh, vice-president of the Federation of All India Medical Association, a national body that represents resident doctors, said at least five students from the medical college were killed on the ground and 50 others were injured.
Who was on board?
Air India said there were 242 people on board, including 229 passengers and 12 crew.
Of those, it said there were 169 Indians, 53 Britons, seven Portuguese and one Canadian.
Former Gujarat chief minister Vijay Rupani was among the dead, according to Sambit Patra, the national spokesman for Prime Minister Narendra Modi's ruling Bharatiya Janata Party (BJP).
Air India boss Campbell Wilson released a pre-recorded video statement saying those injured had been taken to local hospitals.
Loved ones have spoken of their grief following the deaths of their family members.
Fiongal Greenlaw-Meek, and his husband, Jamie Meek, were due to return home on the flight.
Mr Meek's brother told The Times newspaper they "expected him home tonight" in Birmingham.
"He should have landed at 6:30pm and then driven up for about 11 to get his dog who is staying with our mum," Nick Meek told The Times.
"She is not in a good way. It is all very raw for her at the moment. It's a lot to take in and we only heard this news a couple of hours ago."
Remarkably, there were reports of at least one survivor.
The BBC and Indian media reported that person was British national Ramesh Viswashkumar.
It was reported he showed local media his boarding pass, which showed his name and his seat number 11A.
"Thirty seconds after take-off, there was a loud noise and then the plane crashed. It all happened so quickly," Mr Ramesh was reported as saying.
"When I got up, there were bodies all around me. I was scared. I stood up and ran. There were pieces of the plane all around me," he said. "Someone grabbed hold of me and put me in an ambulance and brought me to the hospital."
Why did the plane crash?
There is no consensus among aviation experts on why the plane crashed.
As officials begin investigations, analysts have been focusing on a few key elements, which can be seen in grainy vision of the incident, to try to explain what happened.
Aviation expert Guy Hirst told the ABC it appeared to be "a one-in-a-million chance that a series of events has led to a really sad, sad outcome".
Mr Hirst, a career pilot and aviation educator, has studied the videos of the incident and said he believes the plane suffered from a double engine failure, which could be caused by a few factors.
"Possibly bird strikes … Ahmedabad does suffer quite a lot from flocks of birds, and although they've been doing quite a lot at the airport to try and reduce the possibilities, that is always a possibility," Mr Hirst said.
"It didn't have a high-nose, so it hadn't stalled or anything … it looked like its wings were level — sometimes if there's an engine failure at a critical time, it is possible to have the plane bank at an angle — but that didn't look the case. It looked like it was symmetrical.
"I think probably the most likely is a bird strike or some sort of fuel starvation that caused both engines to lose power at a ridiculously critical timing."
Former pilot and aviation analyst James Nixon studied the footage and told ABC Melbourne the plane's landing gear stayed down the entire time, which was unusual during a "normal" engine failure.
He also said footage showed the plane sinking after taking off normally.
"This is indicative of the pilots pulling up the flaps instead of the landing gear after take off."
When asked what could cause this, he replied "sadly pilot error".
Fellow expert John M. Cox agreed it was too early to make a firm call on the cause, but said investigators will be asking if the plane was properly configured for flight.
Mr Cox told AP that experts will determine if the slats and flaps were in the correct position to help the plane climb.
"The image shows the airplane with the nose rising and it continuing to sink,'' Mr Cox said.
"That says that the airplane is not making enough lift.''
The slats and flaps should be positioned so that the wing enables more lift at lower speeds.
"It's hard to tell but from looking at the aircraft from behind … it doesn't look like that the trailing edge flaps are in the position I would have expected them to be."
What is a Boeing 787 Dreamliner?
The 787 Dreamliner is a wide-body, twin-engine plane, with the Air India disaster the first crash ever of a Boeing 787 aircraft, according to the Aviation Safety Network database.
More than 1,000 787s have been delivered to dozens of airlines around the world, according to the flightradar24 website.
Boeing said it was "working to gather more information" about the crash and was in contact with Air India.
"Our thoughts are with the passengers, crew, first responders and all affected," it said in a statement.
The company's shares dropped about four per cent on Thursday, US time.
What happens next?
An official from India's national disaster response force said they deployed seven teams to the crash site and have recovered 81 bodies so far.
The Hindustan Times reported that one of the two black boxes has been found which will need to be decoded to determine what happened.
While the crash probe continues, local police have said the identification of people killed will take time.
State police official Vidhi Chaudhary said "most of the bodies have been charred beyond recognition", with authorities organising DNA testing.
Indian aviation authorities are leading the probe, with the US National Transportation Safety Board also sending a team, along with Boeing and GE to assist.
"We're there to provide any assistance that India may need as they go through what appears to be a somewhat lengthy investigation on this crash," said the Federal Aviation Admninstration's acting administrator, Chris Rocheleau.
US Transportation Secretary Sean Duffy said their government will not hesitate to implement any safety recommendations that may arise.
Britain said it was working with Indian authorities to urgently establish the facts around the crash and to provide support to those involved, the country's foreign office said.
UK Foreign Secretary David Lammy has reportedly convened a COBRA meeting, which brings together senior government officials to organise responses to emergencies.
Mr Bray and Mr Hirst told the ABC they believed interim findings would be made within the next three to four weeks, but detailed findings could take at least several months.
ABC/wires
