View Full Version : 744 - 2 Hyd or 2 Gen - Land ASAP?

27th Mar 2008, 07:34
Just pondering ....

On the 744 would you divert if you were down to 2 Hyd systems, or 2 Gens?

I notice the QRH doesnt say Land ASAP for a dual Hyd failure, strikes me as strange?

27th Mar 2008, 09:22
The non-normal QRH states:-
"plan to land at nearest airport" - this is not the same as "land ASAP". Although there is a requirement to use Flaps 25 and add 20kts to the Vref Flaps 30, the only other restriction is for a 20kts cross-wind limit, so the crew will need to check the x-wind and landing distance available at the airport they consider "suitable", i.e. it is not considered an emergency situation.
As for electrics, 2 systems out is also not an emergency and flight may continue to destination, but with some restrictions as per checklist.

27th Mar 2008, 13:56
There is also the point to consider why 2 of them fail at the same time, maybe there has been a situation or a maintenance action that made the fail for the same reason. So it's a very serious incident. Depends on the situation.

Generally with 2 out of 4 systems failed and not replacable, you do not continue the flight, unless you have some very good reasons.