NEW DELHI, July 14 (Reuters) - A preliminary investigation into the crash of an Air India passenger jet last month that killed 260 people raises additional questions about the incident and the investigation is far from over, Air India's CEO said in a memo on Monday.

Air India will begin operating three weekly flights between Ahmedabad and London Heathrow from August 1, replacing its existing Ahmedabad-London Gatwick service. The change comes as part of the airline's phased restoration of operations,

Air India will reduce its Bengaluru–London Heathrow service from seven to four weekly flights starting August 1, as part of a broader safety-driven overhaul of its international operations in the wake of the AI171 crash in Ahmedabad last month.

A Golden Chassis from the United States helped download 49 hours of flight data from one of the black boxes of Air India's ill-fated Boeing 787-8 aircraft that crashed last month.