Video of an Air India jetliner that crashed into a neighborhood points to potential anomalies that aviation safety authorities will examine to understand what caused the accident that killed at least 241 people.

The Boeing 787 Dreamliner appeared to not achieve sufficient thrust as it lumbered down nearly the full length of an 3,350-meter runway, a distance that should have been more than enough to take off, said Bob Mann, head of aviation consultant RW Mann & Co.

That could stem from a misconfiguration of the plane prior to takeoff or erroneous weight data entered into the plane’s computer system that determines how much power is needed to get off the ground, he said. Mann cautioned that his views were unofficial and not corroborated by data or cockpit voice recorders, which have yet to be recovered from the site.