I am an Indian citizen, travelling to USA by an American Airlines flight (which is operated by British airways for the first leg). I have a valid tourist/business visa (B1/B2) for USA. My flight will arrive at Terminal 5 at 7 am, and leave from Terminal 3 at 9.30 am at Heathrow, giving me 2.5 hours to make the connection.
I had the following questions -
a) Do I need a direct airside transit visa (DATV) or a visitor-in-transit visa for this connection?
b) Both flights will be on a single ticket. Given this, will I have to pass through UK borders, customs or immigration?
c) Given that I need to move from Terminal 5 to Terminal 3 - are 2.5 hours sufficient to make the connection?