A320 RAT
Joined: Jun 2013
Posts: 326
Likes: 1
From: Or-E-Gun, USA
@ Vilas...
"Can you explain exactly what is your complaint?"
Umm, sure... That otherwise excellent, type rated pilots apparently do not have a deep enough understanding of their machine's backup systems. You said, "complaint," sir, I did not. I'd call it a common concern. Sooner or later, that small, missing bit of functional detail will bite you.
Umm, sure... That otherwise excellent, type rated pilots apparently do not have a deep enough understanding of their machine's backup systems. You said, "complaint," sir, I did not. I'd call it a common concern. Sooner or later, that small, missing bit of functional detail will bite you.
Joined: Jun 2007
Posts: 3,443
Likes: 39
From: Wanderlust
No Fly Zone
Your mention of energy management of RAT is rather vague and appears like a general lament. If you could explain the precise concern will be better. I do believe in knowing details of the systems. But at least if you know what is being achieved by the ECAM procedure that is good enough. Normal and abnormal procedures are presented in much the same way as a car's user manual and if you don not have deeper understanding can leave you feeling uncertain despite completing the full procedure. May be that's what you meant.
Your mention of energy management of RAT is rather vague and appears like a general lament. If you could explain the precise concern will be better. I do believe in knowing details of the systems. But at least if you know what is being achieved by the ECAM procedure that is good enough. Normal and abnormal procedures are presented in much the same way as a car's user manual and if you don not have deeper understanding can leave you feeling uncertain despite completing the full procedure. May be that's what you meant.
Joined: Jun 2014
Posts: 1,052
Likes: 72
From: Village of Santo Poco
Originally Posted by No Fly Zone
Umm, sure... That otherwise excellent, type rated pilots apparently do not have a deep enough understanding of their machine's backup systems. You said, "complaint," sir, I did not. I'd call it a common concern. Sooner or later, that small, missing bit of functional detail will bite you.
But that's just me.
Joined: Jun 2003
Posts: 206
Likes: 0
From: _
So either switch will pop the RAT out, but only the ELEC will force the RAT Gen to power its respective systems. It looks like this is the reason for two switches; the RAT Gen takes priority over the systems it feeds.
So, having a HYD failure, pressing the HYD button will get the RAT out without force powering the RAT AC Gen. If you had a HYD failure and still had serviceable engine generators, but pressed the ELEC switch, you'd pop the RAT, still get hydraulics but you'd also force off the good engine generators (only on those bus bars the CSM/G supplies of course).
So, having a HYD failure, pressing the HYD button will get the RAT out without force powering the RAT AC Gen. If you had a HYD failure and still had serviceable engine generators, but pressed the ELEC switch, you'd pop the RAT, still get hydraulics but you'd also force off the good engine generators (only on those bus bars the CSM/G supplies of course).
If mechanical backup law is true, would there be a case for deploying the EMER GEN if you were reduced to a single electrical source in flight? An electrical malfunction at an ill timed moment could leave you in no man's land whilst the RAT deploys and generator is coupled. Would the EMER GEN just power the essential systems as per ELEC EMER CONFIG and leave the less essential systems to be powered by the remaining IDG? Or would it be more complex?
Joined: Jun 2014
Posts: 1,052
Likes: 72
From: Village of Santo Poco
Port Strobe, I suppose the "big picture" answer to your question would be how likely would it be for the same airplane to suffer what amounts to three separate electrical failures within one flight (the APU gen is deferred, then both IDGs fail in sequence). The "no man's land" scenario you're describing would last approximately 8 seconds (I suppose those could be the longest 8 seconds of a pilot's life under the right circumstances), which is NOT long enough to justify flying around with the RAT deployed, in my view.
Joined: Aug 2007
Posts: 98
Likes: 2
From: Middle East
Port Strobe
Aircraft will not go down to MECH B/UP in the scenario you described because enough HYD power & Electricals (by BATTs) are available. ALTN LAW will activate (with L/G up).
Aircraft will not go down to MECH B/UP in the scenario you described because enough HYD power & Electricals (by BATTs) are available. ALTN LAW will activate (with L/G up).
Joined: Jun 2007
Posts: 3,443
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From: Wanderlust
Port Strobe
Between failure of all electrical sources and deployment of EMER GEN via RAT takes 8 seconds and aircraft is powered by batteries through the inverter, it will go in alternate law with rudder mechanical till FAC 1 is reset, then rudder will also change to alternate. Mechanical back up will happen if there no electrics whatsoever or all computers trip together.
Between failure of all electrical sources and deployment of EMER GEN via RAT takes 8 seconds and aircraft is powered by batteries through the inverter, it will go in alternate law with rudder mechanical till FAC 1 is reset, then rudder will also change to alternate. Mechanical back up will happen if there no electrics whatsoever or all computers trip together.
Joined: Jun 2003
Posts: 206
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From: _
Thanks all who answered, very helpful indeed. I agree it would be a highly unlikely scenario, however if someone had listed all QF32's ECAM procedures here 5 years ago they'd have been shot down. Now I've learned a bit more about mechanical backup I see it was unfounded, but thanks to those for helping.
