Unless the authorities have recently relaxed the minimum system requirements for entering ETOPS areas, my many years of plowing twin Boeings and Airbuses across oceans left me with the distinct memory that the relevant QRH page left no doubt: three functioning hydraulic systems required to fly beyond sixty minutes of an adequate airport.
As for the A330 (I imagine the same general rule to 767 would apply), the loss of single hydraulic is not a cause for diversion unless you don't fit into destination. Neither does it warrant a change in ETOPS once airborne. There is no land ASAP at all. Your capability is degraded to CAT3A, yes, so why divert and land at possible worse off adequate (which might only be a VOR anyway) airfield when home base might be fine with sufficient reserves and runway/weather/you name it. All legal and fine, that's why we fly redundant aircraft, and it so happens the gear gets stuck and is only confirmed once the effort is made to lower it
Can anyone point to a relevant document to tell which of these opinions is correct? No matter what you decide these days, it will be second guessed unless you can point to it in the book (ask me how I know
).
I have seen both views argued in ETOPS training over the years. Of course, I've also been told that you have to proceed to your ETOPS alternate if you lose an engine even if BIKF is CAVOK and nearby (I don't buy this one
).
FAA AC 120-42B, the ETOPS Advisory Circular, has this somewhat generic guidance:
En Route.
(1) PIC Authority. No part of this AC is to be interpreted as reducing the PIC’s joint responsibility for determining that the flight can be safely conducted as planned before release. None of the guidance in this AC may be interpreted in any way to prejudice or limit the final authority and responsibility of the PIC for the safe operation of the airplane.
What this means these days is that we all know whom to blame for the decision to continue or divert.
