True enough, Frozen. When the forecast is good, Macau is used as the alternate. This is, in theory, adequate - Hong Kong has two independent runways, so in good conditions, the second runway essentially counts as another airport. The fuel to Macau on the flight plan is also substantially greater than the fuel required. It's going missed to the east, and a long, drawn out path around the far side of Macau, and landing on 16. In reality, it's a vector or two to the west, to intercept the loc for 34.

When the forecast is poor, Kaohsiung/Taipei/Guangzhou/Manilla etc are loaded on.

When the forecast is typhoons and such like, the alternates are even further afield, Bangkok, for example.

The first issue with this flight, was that the forecast was way off. TAFs indicated (at time of departure) VMC at HKG. That changed, very quickly, and very severely.

I don't recall where their filed alternate was, but in all likelihood it was the fair weather alternate (Macau).

When HKG weather goes pear-shaped, the local alternates fill up extremely quickly. Many only have one runway. Due to the unexpected change in HKG weather, they all filled up very quickly, and were unable to accept further diversions. Mainland China's international airports weren't accepting diversions from HKG. Again, due to the forecast, most long haul flights inbound would have been given a non-mainland alternate anyhow.

Given the complete lack of options presented to this crew, I'd say it was job well done. Something of a nightmare, however, for the passengers and crew after landing. The problem was a lack of immigration control, more than anything. Everyone had to stay on board.

It is alarming, however, to see the Mainland authorities and controllers breach ICAO protocols regarding diversions. Not necessarily on this occasion, but they have been known, on numerous occasions, to deny filed diversions to their airports. Even more alarmingly, the've done so to aircraft declaring fuel emergencies. That is the bigger problem in all of this.

The crew should have been able to have CX OPS arrange a PEK/XMN diversion, if the Mainland weren't so difficult. They frequently do it, but of course, you need to be able to rely on it when the chips are down.

CX fuel policy is very sensible, as it happens, and fuel policy wasn't a causal factor in this. The crew are also very experienced with the options/weather/operations in the area. If you're not familiar with it, it can be very challenging, to say the least.. This was unfortunately a combination of a duff TAF and the Chinese shouting 'CANNOT'.

Something does need to be done, however, regarding the denial of diversions to FILED alternates. That doesn't necessarily relate to this flight, just an ongoing problem.