July 18 (Reuters) - A cockpit recording of dialogue between the two pilots of the Air India flight that crashed last month supports the view that the captain cut the flow of fuel to the plane's engines, said a source briefed on U.S. officials' early assessment of evidence.

The power minister proposed a rule in June requiring air conditioners sold in the country to have thermostats that can be set no lower than 20 Celsius (68 Fahrenheit).

The CEO of Air India sought to draw a line under rife speculation around the cause of last month's air disaster in Ahmedebad, saying the preliminary investigation had ruled out a mechanical cause for the crash.

A cockpit recording of dialogue between the two pilots of the Air India flight that crashed last month supports the view that the captain cut the flow of fuel to the plane's engines, said a source briefed on U.