New Delhi/Ahmedabad, June 12 -- The Aircraft Accident Investigation Bureau (AAIB) is expected to release a status update on Friday on its investigation into the crash of Air India flight 171, nearly a year after the accident, according to officials who asked not to be named. But the document will not establish what brought the aircraft down, with the examination of its engines still underway.

By their account, the update will set out the work completed so far and the areas still under examination, and little beyond that. What it might stop short of doing is settle the question that lies at the heart of the issue: whether the fuel to both engines was cut by human hand or by a fault in the aircraft. That question has split investigators, p...