Plane crash investigations are incredibly complex, and it can take months or even years to identify what went wrong. But video and photos of the Air India crash on Thursday prompted some early thoughts from aviation experts.

A widely shared video of the crash showed the Boeing 787 Dreamliner descending over buildings with its nose pointed upward, an unusual position, said John Cox, a former airline pilot and chief executive of Safety Operating Systems, a consulting firm.

The plane’s position looks as if “it should be climbing, and in fact it’s descending,” he said. “The question is why.”

Mr. Cox and other experts cautioned against jumping to conclusions. Planes and the aviation system have many redundancies to prevent a single problem from leading to a calamity. As a result, crashes are typically caused by multiple failures, which can include equipment malfunctions, improper maintenance, bird strikes or pilot error. Early hypotheses often are ruled out during lengthy, technical crash investigations.

Officials looking into the crash will have no shortage of questions to ask, said Greg Feith, a former investigator at the National Transportation Safety Board.

“Did they properly configure the airplane when it took off? What was occurring with them? Was there a loss of thrust?” he asked. “Was there fuel contamination? Fuel starvation where both engines weren’t getting fuel that would have caused a loss of thrust on both engines?”