Originally Posted by
Officer Kite
Basically, considering we have all these wonderful backup systems, 3 on Airbuses I believe at least, why is it such a big deal when we lose the main system? Why can't we just switch to the 2nd back up, if that goes, then switch to the final back up? It happens quite regularly, most recently with an Aer Lingus A333 out of Dublin, that when the main hydraulic system fails, it requires a return to base and there doesn't even seem to be enough pressure in the hydraulic system to raise the landing gear bay door, which I believe are even blown out by an accumulator (which I had in mind as being last resort for when
really hits the fan and you've nothing) ... but what about the 2 back up systems? are these not as good?
Hi,
As you correctly interpret, technically speaking losing 1 hydraulic out of 3 is not a big deal per se, but, like most of the time in aviation, it all depends on the context. There are various aspects to consider in that case, such as flight time and conditions (would you go for a 12 hours etops overwater flight with the minimum amount of en route alternates on 2 hydraulics ?) , systems affected by the hydraulic loss (maybe now you're performance limited and your landing distance at destination and/or alternate(s) is not ensured), multiple failures (maybe you have left with an MEL item and with another failure you find yourself in a degraded condition), maintenance facilities at destination (no maintenance and/or much more expensive to have the airplane tech there than coming back to land at home base, this is generally discussed with your company ops) and so on. During your training you will learn how to integrate the pure technical aspects of the airplane with all the other environmental factors and come up to a decision with your colleague(s).