THE Air India plane crash generated so much heat that it might have melted the aircraft’s black boxes, investigators warned.

As grieving families agonisingly wait for answers, authorities rushing to work out the cause of the incident have cautioned the inquiry could take a long time.

The London-bound Air India aircraft, a Boeing 787 Dreamliner, crashed on a medical college hostel soon after taking off from the western city of Ahmedabad.

Only one passenger survived the crash, while 241 people on board and 29 on the ground were killed in one of India’s worst aviation disaster in decades.

Amit Singh, a former pilot and an aviation expert, said the recovery of the flight data and cockpit voice recorders – or black boxes – are crucial to piece together the sequence of events.

Planes usually carry two black boxes, which are small but tough electronic flight data recorders.

One records flight data, such as altitude and speed, whilst the other monitors the cockpit sound.

But whilst both devices are designed to survive accidents, investigators have warned the heat generated from the crash could have melted the boxes.

The first was recovered from a rooftop near where the plane came down just 28 hours after the crash.

We already know that the pilot, Captain Sumeet Sabharwal, made a desperate mayday call to air traffic control in the moments before the disaster.

He cried out: “‘Thrust not achieved […] falling […] Mayday! Mayday! Mayday!”

The two pilots then wrestled for 17 seconds with the controls as the jet sank through the air before careening into the buildings below.

Sabharwal had 22 years of experience and had racked up 8,200 in the air.

The plane gained just a few hundred feet of altitude when the power apparently cut out, killing more Brits than any air disaster since 9/11.

Singh said the investigating authorities will scan CCTV footage of the nearby area and speak with witnesses to get to the root cause of the crash.

Investigators will also study the pilot training records, total load of the aircraft and any thrust issues related to the plane’s engine.

The Indian government has also set up a separate committee to examine the causes leading to the crash and work out ways to prevent a disaster like this happening again.

But despite the large cohort of investigators working to find out what happened on that fateful flight, aircraft bosses warned it could take some time because of the “charred” plane.

The committee is expected to file a preliminary report within three months.

Authorities have also begun inspecting and carrying out additional maintenance and checks of Air India’s entire fleet of Boeing 787 Dreamliners to prevent any future incident.

Air India has 33 Dreamliners in its fleet.

The plane that crashed was 12 years old. Boeing planes have been plagued by safety issues on other types of aircraft.

There are currently around 1,200 of the 787 Dreamliner aircraft worldwide and this was the first deadly crash in 16 years of operation, according to experts.

Since the devastating incident Air India has cancelled multiple scheduled flights.

Flight AI 159 was planned to depart Ahmedabad, India, at 1.10pm local time on Tuesday, and arrive at Gatwick airport at 6.25pm BST.

Air India’s website shows the flight was initially delayed by one hour and 50 minutes but was later cancelled.

A flight from Gatwick to Amritsar, India, set to depart at 8pm BST was also axed, as well as Paris-bound flight AI143 from Delhi.

The cancelled flights were scheduled to be operated by a Boeing 787-8 Dreamliner, which is the same type of aircraft that crashed on June 12.