Now the focus seems to be on whether one of the pilots turned the fuel switches off or if a computer or electrical 'glitch' caused the fuel to shut off despite the switches being in the on position.

The plot thickens.

And, a few pilots have commented on the lack of video cameras recording what goes on in the cockpits of aircraft... it would make it a lot easier to see who operated which switch or control, etc.

Should have been mandated a long time ago.

Air India was warned about wrongly installed fuel switches more than six years before a crash that killed 260 people, it was revealed yesterday.

Investigators are probing how two fuel switches in the cockpit of Air India Flight 171 were turned off shortly after take off, resulting in a catastrophic loss of power and the aircraft crashing to the ground.

The switches' 'locking feature' meant pilots had to lift them up before changing their position.

But a preliminary report by India's Aircraft Accident Investigation Bureau (IAAB) said yesterday that in December 2018 the US air regulator Federal Aviation Administration (FAA) warned airlines that fuel switches had been installed in some Boeing 737s 'with the locking feature disengaged'.

'If the locking feature is disengaged, the switch can be moved between the two positions without lifting the switch during transition, and the switch would be exposed to the potential of inadvertent operation,' the FAA warned in a Special Airworthiness Information Bulletin.

'Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown.'

It recommended airlines inspect the switches, including 'whether the fuel control switch can be moved between the two positions without lifting up the switch'.

Air India has suggested such inspections were not carried out because the FAA's bulletin was 'advisory and not mandatory'.

Investigations into the Air India plane crash are looking into the pilots' medical records as it's claimed one of them had depression and mental health issues.

Captain Sumeet Sabharwal, an experienced pilot with more than 8,200 hours in the cockpit, was piloting the Boeing 787 Dreamliner when it plummeted into a residential area, called Meghani Nagar, killing 241 people on board and claiming 19 more lives of those on the ground.

Seconds after taking off on June 12, two fuel switches in the cockpit of Air India Flight 171 were turned off shortly after take off, resulting in a catastrophic loss of power and the aircraft crashing to the ground.

The switches' 'locking feature' meant pilots had to lift them up before changing their position, they are not simple push buttons which can be accidentally turned off.