Less than 40 seconds.

Recently, Air India Flight 171 was given airborn time before drowning in a densely populated neighborhood in Ahmedabad in one of India’s rare aviation disasters in memory.

Investigators now faced a serious task of shifting through the rubble and decoded together to simultaneously to do the sound of the Cockpit of Boeing 787 Dreamliner and Flight Data Records, which became terriblely wrong in seconds after the take-off. Under international rules set by United Nations Aviation Body ICAOA preliminary investigation report should be released within 30 days, ideally completed within 12 months with the final report.

London Gatwick-Bound Aircraft piloted by Captain Sumit Sabarwal and co-pilot Clive Kundar, western Indian city of Ahmedabad at 13:39 local time. [08:09 GMT] On Thursday, 242 people and with about 100 tonnes of fuel on the board. Within moments, May 1 was cracked from the cockpit. This will be the final transmission. This was followed by a loss of height and an accident surrounded by flames.

Captain Kishore Chinta, a former explorer of the Bureau of Aircraft Accident Investigation of India, called it “rare” of “rare” accidents – a controlled flight in the area after 30 seconds of the take -off. “For my knowledge, nothing has happened,” he told the BBC.

Did both engineers fail due to bird strike or fuel contamination? While reducing the lift on a heavy loaded jet in the extreme summer, flaps were unfairly extended? Was there a maintenance error during engine servicing? Or the action of an unknown crew cut fuel to both engines?

The investigators will investigate all these possibilities – and much more. The investigation of the air accident rely on triangle and elimination – matching the physical evidence with the debris with the aircraft performance data recorded to create a consistent picture of what went wrong.

Every scorched cable, damaged turbine blades, airplane maintenance logs, and fly data and cockpit voice recorders will be tested for signals and sounds – the so -called “black box”. The BBC spoke to accident experts to understand how the investigation would proceed.

Seriously, the first clue on the ground could come from the debris of two engines, at least three investigators said.

Peter Goelz, former Managing Director of the National Transportation Safety Board (NTSB) of the US, says, “You can tell the loss whether the engine was creating power in the effect – turbine fractures separately, different,”. “The first clue of what went wrong is.”

Turbines are important rotating components that play an important role in extracting energy to generate thrust.

“If the engine was not producing power, then the investigators have a serious matter – and the attention will be quickly transferred to the cockpit.”

What happened in the cockpit is Boeing 787’s enhanced Airborn Flight Recorder (EAFRS) – or “Black Box” – which, investigators say, will help tell the story. (Indian officials say the recorders have been recovered from the accident site.)

These devices capture broad flying data and cockpit audio – from pilot radio calls to ambient cockpit sounds. Voice recording comes from individual pilot mix, radio transmission and an area microphone that raises background noise in the cockpit.

Data recorder track Status of gear and flap liver, thrust settings, engine performance, fuel flow and even fire handle activation with high precision.

“If the flight data recorder shows that the engine was making full power, the attention would run on flap and slats. If they are extended as required, it becomes a very difficult investigation,” says Sri Goelz.

Flap and slats increase the lift at a low speed, which helps to take off an aircraft and is safely landed by allowing to fly slowly without stalling.

“If [the trail leads] For a problem in the flight management control system, it will increase serious concerns – not only for Boeing, but for the entire aviation industry. ,

The flight management control system of Boeing 787 is a high automatic suit that manages navigation, performance and guidance. It integrates data from several sensors to customize the flight path of the aircraft and fuel efficiency.

With more than 1,100 Boeing 787 flying worldwide since 2011, investigators must determine whether it was a systemic issue that could affect the global fleet – or a failure is unique for this flight, says experts. “If it points to the problem of a system, regulatory bodies will have to make some difficult decisions very quickly.”

So far, there is no indication of mistake on one’s part. The Ministry of Civil Aviation of India said on Tuesday that 24 of Air India’s Boeing 787 fleet inspection – 24 of the 33 aircraft have been investigated so far – “not revealed any major security concern,” saying that aircraft and maintenance systems complied with existing standards.

Boeing President and CEO Kelly Ortberg said on June 12: “The Boeing will postpone India’s Bureau of Access Investigation (AAIB) for information about Air India Flight 171 as per the United Nations ICAO protocol.”

Decoding of data in AAIB The lab in Delhi will be headed by Indian investigators, which will have Boeing, engine-maker GE, Air India and experts of Indian regulators. Investigators from NTSB and UK will also participate.

“In my experience, teams can usually determine what happened quite hurry,” Sri Goelz says. “But to understand why it may take longer.”

Other clues can be found from debris. “Every part – wire, walnuts, bolts – will be collected carefully,” Sri Chinta says.

Typically, the debris is taken to a nearby hangar or safe feature, kept to identify the nose, tail and wingtips, and then paper together. In this case, depending on what flight data and voice recorders reveal, a complete reconstruction may not be necessary, the investigators say.

Investigators say the importance of debris varies from accidents. For Malaysia Airlines flight MH17, shot in Eastern Ukraine in July 2014, it was important – the reconstruction of the nose revealed a clear strash damage from the Russian -made missile.

In the debris, investigators will also check fuel filters, lines, valves and residual fuels to check contamination – something that is easy to find or rule, said a crash explorer who preferred to be anonymous, said. In addition, he believed that fuel -filled equipment used before departure was “probably quarantine and already inspected”.

This is not all. Investigators will collect a record of maintenance and mistake from the airline and Boeing’s Acars (aircraft communications addressing and reporting system), which transmits data to both Boeing and Air India through radio or satellites, says Mr. Chinta.

They will review all the flights run by the aircraft and crew in recent months, as well as with corrective action taken before issuing the aircraft for technical log and service of pilot-reported defects.

Investigators will also examine pilot licenses, training records, simulator performance and instructor comments – in which pilots handled landscapes such as engine failures in advanced flight simulator. “I think Air India must have already provided these records to the investigation team,” called Mr. Chinta.

Investigators will review the service history of all components of the aircraft that were removed and replaced, investigating the defects reported for any recurring issues – or signs of problems that could affect this flight.

“These investigations are exceptionally complicated. They take time, but will be the initial indicators of whether the possibility has gone wrong,” Sri Goelz says.

A big reason is how far the technology has come. He says, “One of the first accidents I investigated in 1994 was going to monitor only four parameters in the flight data recorder.”

“Today’s recorders capture hundreds – if not thousands – every second. Alone we change the way you investigate accidents.”

Follow BBC News India Instagram, YouTube, Twitter And Facebook,