I was on one return flight when SHA ATC cleared a fully loaded CX L1011 (RB211-22B engines) to 12,000 metres which brought hilarious laughter from the crew. It took quite a bit of chatter to convince ATC they were asking for the impossible.
CX was fairly lucky and as far as I can recall and never had a major mechanical problem with the Tristar at SHA (had plenty everywhere else the damn thing flew!). I think one got stuck overnight with snow on the wings and lack of deicing equipment/snow clearing gear etc.