with qualifying status / class of travel when riding Cathay Pacific (T4), can one does the following?
Check in (T4)
Take landside shuttle to T1
Security (T1)
Access Qantas Lounges and British Airways lounge (T1)
Take airside shuttle to T4
Boarding (T4)

What airport are you asking about?

Singapore Changi

T1 at SIN has security at the gate, so you would normally clear immigration shortly after check-in, but you wouldn't clear security until immediately before your flight. IIRC, T4 has a more traditional (to me) flow, with check-in, security, and immigration one after the other, letting you into a secure airside area. Given the different schemes of the two terminals, I can't see how this could possibly work. (I.e. you won't really be "airside" in T1, so how could you take an airside shuttle to T4?)

Plus this is Singapore. You're not likely to encounter a great deal of flexibility from the immigration and security people.

Why do you want to do this? The QF and BA lounges are nice enough, but I wouldn't say that they're better than the CX lounges I've been in (although I haven't been in their T4 SIN lounge).

In this context from SIN T1 it really means "Take train to T2 and then take post emigration / Transit Hall shuttle to T4".


http://www.changiairport.com/content...lish_LoRes.pdf