A320 hydraulic problem at DEN
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A320 hydraulic problem at DEN
Plane landing at DIA towed to gate - The Denver Post
In short, the report says that UA418 landed safely on 34L at DEN with a total hydraulic failure. As in NO control surfaces.
Has anyone here heard anything about this? The story has received virtually no attention, suggesting either the media is incorrect either about the extent to which the airplane was crippled, or simply has no idea what a "total hydraulic failure" generally means for the folks trying to fly the airplane.
As I understand it, an A320 that's lost all three hydraulic systems has no control whatsoever other than differential thrust, ala UA232. "Mechanical Backup", the mode to which the plane reverts in the event of a complete electrical failure, simply allows for the manual adjustment of the hydraulic valve of one of the trim tabs.
*Update: Just heard from a family friend with the FAA - so far, the official line from them is "Landed with total hydraulic failure."
In short, the report says that UA418 landed safely on 34L at DEN with a total hydraulic failure. As in NO control surfaces.
Has anyone here heard anything about this? The story has received virtually no attention, suggesting either the media is incorrect either about the extent to which the airplane was crippled, or simply has no idea what a "total hydraulic failure" generally means for the folks trying to fly the airplane.
As I understand it, an A320 that's lost all three hydraulic systems has no control whatsoever other than differential thrust, ala UA232. "Mechanical Backup", the mode to which the plane reverts in the event of a complete electrical failure, simply allows for the manual adjustment of the hydraulic valve of one of the trim tabs.
*Update: Just heard from a family friend with the FAA - so far, the official line from them is "Landed with total hydraulic failure."
The Denver Post story is just another example of why the media these days has so little credibility and is emminently worth ignoring.
No nosewheel steering likely means a green system failure; two other systems remain, the blue and yellow. I've had such a failure on a 330 and it actually taxis and turns quite well using a bit of differential braking to caster the nosewheel, at least to get the aircraft off the active.
No nosewheel steering likely means a green system failure; two other systems remain, the blue and yellow. I've had such a failure on a 330 and it actually taxis and turns quite well using a bit of differential braking to caster the nosewheel, at least to get the aircraft off the active.
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Total Hydraulic failure sounds pretty bad.
Not rated on the Airbus but I was lead to believe that with no hydraulics whatsoever you still have differential thrust and pitch control through trimwheel?
Should atleast give some control.
Somebody with experience care to comment?
Not rated on the Airbus but I was lead to believe that with no hydraulics whatsoever you still have differential thrust and pitch control through trimwheel?
Should atleast give some control.
Somebody with experience care to comment?
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Well, total hydraulic failure on anything and you're probably dead. This whole thing sounds so unlikely, so I was hoping an entity within the great PPRUNE hivemind had some information closer to the source.
A friend of mine is a 320 instructor, so I'm familiar with the hydraulic systems and reversion logic on the 'bus. The Post isn't the only news outlet saying "total" failure, which is why I'm curious.
A friend of mine is a 320 instructor, so I'm familiar with the hydraulic systems and reversion logic on the 'bus. The Post isn't the only news outlet saying "total" failure, which is why I'm curious.
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you still have differential thrust and pitch control through trimwheel?
Well, total hydraulic failure on anything and you're probably dead.
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Correction: Total hydraulic failure on anything with no control cables and you're probably dead. UA232 pulled off a crash landing with about a 2 out of 3 survival rate, and a DHL crew managed to land an older Airbus in Iraq after it lost all hydraulics, but it's still not a good place to be.
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Had an examiner that once asked me on the sim briefing - What happens if you loose all HYD? I answered something along the lines "We're f$#%&d". He said "That's right, you bend over and kiss your own a@@ goodbye!".
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Evergreen aviation consultant Mike Boyd called the incident serious. "It was an emergency, no question," said Boyd.
But he said the Airbus A320 is such an advanced aircraft and United pilots so well trained that the passengers were never in danger.
But he said the Airbus A320 is such an advanced aircraft and United pilots so well trained that the passengers were never in danger.
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As posted in the Aviation Herald
Incident: United Airlines A320 near Denver on Oct 21st 2009, hydraulics failure
By Simon Hradecky, created Thursday, Oct 22nd 2009 06:50Z, last updated Thursday, Oct 22nd 2009 06:50Z
A United Airlines Airbus A320-200, registration N497UA performing flight UA-418 from San Diego,CA to Denver,CO (USA), was on approach to Denver International Airport, when the crew reported the failure of one of the three hydraulics systems on board indicating, they'd need to be towed off the runway after landing. Emergency services assumed their stand by positions for the arrival. The airplane landed safely on runway 34L and was towed off the runway.
FlightAware > United Air Lines Inc. #418 > 21-Oct-2009 > KSAN-KDEN
By Simon Hradecky, created Thursday, Oct 22nd 2009 06:50Z, last updated Thursday, Oct 22nd 2009 06:50Z
A United Airlines Airbus A320-200, registration N497UA performing flight UA-418 from San Diego,CA to Denver,CO (USA), was on approach to Denver International Airport, when the crew reported the failure of one of the three hydraulics systems on board indicating, they'd need to be towed off the runway after landing. Emergency services assumed their stand by positions for the arrival. The airplane landed safely on runway 34L and was towed off the runway.
FlightAware > United Air Lines Inc. #418 > 21-Oct-2009 > KSAN-KDEN
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Mike Boyd is a God-damned idiot. He has shown on every available occasion a complete lack of knowledge of aircraft systems, to say nothing of his lack of knowledge in many other aviation-related fields. He remains the go-to "expert" in these matters because the reporters don't know any better.
A320 pitch trim is electric, no hydraulics required.
IIRC the rudder has mechanical backup, so no hydraulics required.
Differential thrust and gravity gear drop complete everything you need to land, apparently the airbus test pilots land in this configuration as their party piece so it is possible.
However, the chances of loosing everything hydraulic when you have three independent systems with yellow and green engine driven pumps (that can operate with a windmilling engine as low as 7% n2), blue and yellow electric pumps, yellow to green (and vice versa) PTU and a blue RAT are, shall we say, slim.
LD
IIRC the rudder has mechanical backup, so no hydraulics required.
Differential thrust and gravity gear drop complete everything you need to land, apparently the airbus test pilots land in this configuration as their party piece so it is possible.
However, the chances of loosing everything hydraulic when you have three independent systems with yellow and green engine driven pumps (that can operate with a windmilling engine as low as 7% n2), blue and yellow electric pumps, yellow to green (and vice versa) PTU and a blue RAT are, shall we say, slim.
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A320 pitch trim is electric, no hydraulics required.
Read your FCOMS! the trimmable horizontal stabilizer (THS) is actuated by the green and yellow hydraulic systems..those two gone, stab is not moving...
Electrically controlled, yes, but hydraulically actuated..if the electrics are gone, the THS may be moved by the wheel manually, but there is still a requirement for hydraulic pressure from at least the green, or yellow system..
Rudder?? requires pressure from at least one of 3 systems..but again, no electrics..
Mechanical backup is a bit of a mis-nomer IMHO, not to be confused with manual reversion
Read your FCOMS! the trimmable horizontal stabilizer (THS) is actuated by the green and yellow hydraulic systems..those two gone, stab is not moving...
Electrically controlled, yes, but hydraulically actuated..if the electrics are gone, the THS may be moved by the wheel manually, but there is still a requirement for hydraulic pressure from at least the green, or yellow system..
Rudder?? requires pressure from at least one of 3 systems..but again, no electrics..
Mechanical backup is a bit of a mis-nomer IMHO, not to be confused with manual reversion
Last edited by ironbutt57; 23rd Oct 2009 at 05:44.
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Thing to remember with the airbus is that it's a BIG difference between loosing pressure (pump) or loosing hydraulic fluid / HYD overheat. Engine driven pump for green system, engine driven pump and ram air turbine for blue and finally engine driven and electrical pump for yellow. Add to that a PTU to transfer pressure between green and yellow. Any one of them operating and you will have control but with limited protections and automatics all depending on which system is operating.
All three gone? I still stand by my point, no control.
All three gone? I still stand by my point, no control.
