Every scorched cable, nut and bolt will be examined along with the black box to determine why it went down 30 seconds after take-off.

Investigators believe the Air India Boeing Dreamliner had its emergency-power generator operating when it crashed last week in India's Ahmedabad, the Wall Street Journal reported on Wednesday citing people familiar with the probe.

The black boxes will provide cockpit conversations and data related to the plane's engine and control settings to investigators and help them in determining the cause of the crash.