As has already been stated, the flight crews were limited to fourteen days away, unlike the cabin crews. This caused problems in the case of disruption. So, in 1978, BA introduced Australian postings. Flight crews would spend four months based in Sydney (initially the base was Melbourne but moved to Sydney after a few months).
The main 747 operation was London-Muscat-Singapore-Sydney, then to either Brisbane or Melbourne and London-Bombay-Perth-Melbourne-Auckland. The Sydney based crews would operate all services south of Singapore and Bombay.
This was pre mobile phones and Internet, so how family communications if any could be made.
The short answer is that we didn't communicate once away, except for the odd letter. I realise that this is totally alien to the modern generation, but the need for constant communication hadn't developed yet. Phoning from hotels was stupidly expensive.
What notice of these long trips did you receive, to enable family life to be organized.
Sometimes very little. Nowadays under bidline rules, BA can only use you during the days when you should have been working. However, in the 70's there was no such protection. I was assigned a two week trip at the beginning of the month so arranged our social activities during the second half of the month. BA then cancelled the trip and gave me a two week trip at the end of the month.
Question what is the "C bird" trip.
BA employed nationally based stewardesses. These ladies always operated the 'C' position. A UK based stewardess would operate a random trip, often with many positioning sectors so as to operate the sectors where a national stewardess was not carried.
How many crew ended up in long term relationships.
Of the 24 pilots on my Hamble course who joined BOAC, six divorced and eighteen are still married. I celebrate 40 years of marriage next month.