Hydraulic Failures


New Member
Hiya, I have been looking for a schematic but can't find one so I will go from the top of my head...
What happens if their is a complete engine failure on a FBW aircraft such as the 777 or A3x0? You loose the engine driven hydraulic pumps and the main buses therefore the electrical driven pumps also. What happens if the RAT fails to extend? You are left without any hydraulics and their is no manual reversion. What do you do??? Aysemtric (SP?) thrust is out of the question (no engines!) so how do you stear the thing? Also do you loose the EFIS displays?
Geeeez, that's a lot of failures...

I'd say if all that happened you have to consider one other thing, collision avoidance....Because there are going to be a lot of pigs flying!!!
Only two baronman, lets say their is a midair and the engines ingest parts of some poor guys cessna and the RAT gets mangled too. Or lets say the engines go due to fules starvation and the RAT gets stuck dues to poor tech work or whatever. I know that if the engines fail you are left without hydraulics so thats what the RATs for. My question is what happens if it gets stuck?
I have an answer....
Bend over and ki$$ y0ur @$$ g00dby3.
Just kidding. I'll leave it up to the experts.
Do a search for a recent post by A300capt - it's a story that is very similar to your scenario and the ensuing discussion answers a lot of your questions.
Here is what I wanted to show you. Except imagine your face on his head come on load faster...... this college 56k is killing me argghh
ok here it is........................
How do you steer the thing....

You forget that airliners have an APU in the tail that has a generator strong enough to power the entire aircraft, which will most likely include an electrical hydraulic pump.

But if you lose:

yep, you've got problems!
this college 56k is killing me argghh

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I am not sure if anyone else caught this, but Yaro, what kind of college are you going to that has 56 K?
I am not sure if anyone else caught this, but Yaro, what kind of college are you going to that has 56 K?

[/ QUOTE ]

No kidding...
I think the man to ask is Capt. Al Haynes, he had a similar problem at sioux city......he is an awsome pilot, I had the opportunity to listen to him speak at our school once.
You'd have to be having a really bad day in this "what if" scenario to have this many system failures.

First, if both engines quit at the same time, the RAT will (should) automatically deploy (B757/767) or, is manually deployed by handles in the cockpit (A300). The RAT will power the primary flight controls with trapped stand pipe protected hydraulic fluid in the event of a major hyd leak and no other hyd system is available up to around 130 kts.

ETOPS aircraft also have internal HDG's (hydraulic driven generators) to electrically power things such as the Capt's instruments, navigational systems and some other important electrical items. The HDG kicks in automatically if there is a loss of all AC power (dual engine or generator failure).

All AC/DC electrical power can normally be restored by either getting an engine going or cranking the APU which has the same generator as the engine generators and can also pressurize the aircraft up to around 20,000ft.

If you lose the engines, APU, HDG, RAT and all hydraulic fluid (a highly unlikely scenario), you're probably SOL. You can hope the windmilling engines produce enough residual hyd pressure to the primary flight controls in order maintain some sort of control at higher speeds.
what I meant to say was i was comparing it to a 56k. The PC's in our school have broad band connection. But there are like 5 computers who use the same port so the connection feels a bit like a 56k.