A320ceo barking dog question

jetwet1 · Fri Dec 14, 2018 11:30 pm

I've spent the last week flying in and out of LHR on (sadly) BA's 320.

The first one was (judging from the cabin) an older 320 and the dog was barking like a pitbull on crack, the next couple were on newer aircraft (new style cabin, mood lighting etc) and no dog.

I did do a search, but couldn't find a clear answer (using my phone so searches are brutal), did Airbus change something to reduce the "barking" on later ceo's ?

LH707330 · Sat Dec 15, 2018 12:19 am

Yes, my uncle worked on the design for it when he was at LHT. They were tasked with making the 320s quieter, and came up with the VG to eliminate the A320 howl in 2014, IIRC. Next, they installed a muzzle on the pit bull with a kevlar strap, which was an improved design over the earlier nylon was, as it brought an MBTF of 10k flight hours. It went into series production on l/n 3535.

N766UA · Sat Dec 15, 2018 7:10 pm

I believe it's SOP at most airlines now to have the ramp agents feed them immediately upon opening of the cargo door, just to keep the noise to a minimum.

WPvsMW · Sat Dec 15, 2018 8:08 pm

It's a work-around at Airbus, in view of multiple Boeing patents on bark-suppression. Sometimes the dogs has emotional swings the 1st gen. CECS (Canine Emotional Control System) can't handle, and feeding doesn't work. The second generation CECS was introduced on the A321.

WIederling · Sat Dec 15, 2018 8:47 pm

WPvsMW wrote:
It's a work-around at Airbus, in view of multiple Boeing patents on bark-suppression. Sometimes the dogs has emotional swings the 1st gen. CECS (Canine Emotional Control System) can't handle, and feeding doesn't work. The second generation CECS was introduced on the A321.

So that is what the K-9 department is for at Airbus XFW.
Saw some job notices in the Hamburger Abendblatt but it didn't make any sense at the time.

WPvsMW · Sat Dec 15, 2018 8:58 pm

Exactly, the rumor is there's demand for a pax version for holiday trips to the Med.

LH707330 · Sun Dec 16, 2018 2:58 am

I've heard sometimes they've also been able to do double duty as emotional support animals in the cabin....

greg85 · Sun Dec 16, 2018 10:22 am

You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

Caryjack · Wed Dec 26, 2018 10:43 pm

greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I heard this dog on a Delta A-330 (SEA-AMS). It barked from the start of the outbound taxi until the takeoff roll. I'd guess that the delayed barking occurred because the larger airliner required extra time for the pump to equalize pressure. It was funny to me and I quietly laughed most of the way out.

http://www.askthepilot.com/questionansw ... us-noises/

From the link: "This pertains to twin-engine Airbus models: the A320 series (includes the subvariants A319 and A321) and the larger A330."

Thanks,
Cary

DFW17L · Thu Dec 27, 2018 12:23 am

Caryjack wrote:
greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I heard this dog on a Delta A-330 (SEA-AMS). It barked from the start of the outbound taxi until the takeoff roll. I'd guess that the delayed barking occurred because the larger airliner required extra time for the pump to equalize pressure. It was funny to me and I quietly laughed most of the way out.

http://www.askthepilot.com/questionansw ... us-noises/

From the link: "This pertains to twin-engine Airbus models: the A320 series (includes the subvariants A319 and A321) and the larger A330."

Thanks,
Cary

Wouldn’t it be a howl if the barking sounded like Jingle Bells?

Starlionblue · Thu Dec 27, 2018 2:31 am

Caryjack wrote:
greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I heard this dog on a Delta A-330 (SEA-AMS). It barked from the start of the outbound taxi until the takeoff roll. I'd guess that the delayed barking occurred because the larger airliner required extra time for the pump to equalize pressure. It was funny to me and I quietly laughed most of the way out.

http://www.askthepilot.com/questionansw ... us-noises/

From the link: "This pertains to twin-engine Airbus models: the A320 series (includes the subvariants A319 and A321) and the larger A330."

Thanks,
Cary

I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I think you mean the Yellow system Engine Driven Pump.

CLTRampRat · Thu Dec 27, 2018 4:57 pm

One of the funnier moments from my Ramp Agent Days was a Frontier F/O who had never heard the barking dog before.

They were doing a crew swap so he was on the ramp with us when the plane arrived so he could immediately do the walk around. We are opening the cargo doors and as always the Airbus is barking. The pilot goes “Hey, what the ____ is that?!”

“What?”
“That!” *flails at plane*
“Sir?”
“That sound!”
“Sir that’s the hydraulics.”
“Does it always do that?”
“Yessir, every Airbus with any airline.”
“Huh, never heard that before!”

Sigh...

Starlionblue · Fri Dec 28, 2018 1:53 am

CLTRampRat wrote:
One of the funnier moments from my Ramp Agent Days was a Frontier F/O who had never heard the barking dog before.

They were doing a crew swap so he was on the ramp with us when the plane arrived so he could immediately do the walk around. We are opening the cargo doors and as always the Airbus is barking. The pilot goes “Hey, what the ____ is that?!”

“What?”
“That!” *flails at plane*
“Sir?”
“That sound!”
“Sir that’s the hydraulics.”
“Does it always do that?”
“Yessir, every Airbus with any airline.”
“Huh, never heard that before!”

Sigh...

To be fair to the guy, from the cockpit you don't hear a lot of the stuff that is quite apparent mid-cabin or outside. And the Airbus FCOMs don't really talk about the sounds that stuff makes.

stratclub · Fri Dec 28, 2018 7:32 am

The Boeing EICAS is strangely silent about sounds and smells as well.

Apprentice · Fri Dec 28, 2018 9:13 am

Hi: A320 need hydraulic pressure, before engine start, for: Brakes, Steering, Flight Control Check (High demanding), flaps/Slats positioning, (also high consumption) and... So, if not Engine 2 is not on, You need to use electrical pump for that, there You have your barking noise.
Even, with engines on, while taxing, during checks, if You have High Consumption demand, electric pump will start pumping automatically, when Hyd Pressure will be below certain level.

Hi

Starlionblue · Fri Dec 28, 2018 10:27 am

Apprentice wrote:
Hi: A320 need hydraulic pressure, before engine start, for: Brakes, Steering, Flight Control Check (High demanding), flaps/Slats positioning, (also high consumption) and... So, if not Engine 2 is not on, You need to use electrical pump for that, there You have your barking noise.
Even, with engines on, while taxing, during checks, if You have High Consumption demand, electric pump will start pumping automatically, when Hyd Pressure will be below certain level.

Hi

Maybe I'm misunderstanding you but you don't need brakes, steering, flight controls or flaps/slats movement before engine start.

Apprentice · Fri Dec 28, 2018 4:53 pm

Hi, it depends on company’s proccedure, normally You do a Truck assisted push-back, and when push back is finished, You ask for brakes on, remove to bar and activate Steering. Only then You are cleared for engine start.
Should You strat with no brakes set and not steering control, imagine.
Flight Control checks and flaps/Slats positioning, depend on the company pro.

Apprentice · Fri Dec 28, 2018 4:53 pm

Hi, it depends on company’s proccedure, normally You do a Truck assisted push-back, and when push back is finished, You ask for brakes on, remove to bar and activate Steering. Only then You are cleared for engine start.
Should You strat with no brakes set and not steering control, imagine.
Flight Control checks and flaps/Slats positioning, depend on the company pro.

greg85 · Fri Dec 28, 2018 8:39 pm

Starlionblue wrote:
Caryjack wrote:
greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I heard this dog on a Delta A-330 (SEA-AMS). It barked from the start of the outbound taxi until the takeoff roll. I'd guess that the delayed barking occurred because the larger airliner required extra time for the pump to equalize pressure. It was funny to me and I quietly laughed most of the way out.

http://www.askthepilot.com/questionansw ... us-noises/

From the link: "This pertains to twin-engine Airbus models: the A320 series (includes the subvariants A319 and A321) and the larger A330."

Thanks,
Cary

I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I think you mean the Yellow system Engine Driven Pump.

No, I mean yellow electric pump. I’m talking about taxi with engine number 1 only.

Apprentice · Sat Dec 29, 2018 2:58 am

Hi: and how to pressurize remaining 2ea systems?
For instance, with only eng #1, how did You pressurized System #3, to keep LG extended w/o Landing Gear safety pins? Or how to turn Nose Gear?
Rgds

stratclub · Sat Dec 29, 2018 4:28 am

Starlionblue wrote:
Apprentice wrote:
Hi: A320 need hydraulic pressure, before engine start, for: Brakes, Steering, Flight Control Check (High demanding), flaps/Slats positioning, (also high consumption) and... So, if not Engine 2 is not on, You need to use electrical pump for that, there You have your barking noise.
Even, with engines on, while taxing, during checks, if You have High Consumption demand, electric pump will start pumping automatically, when Hyd Pressure will be below certain level.

Hi

Maybe I'm misunderstanding you but you don't need brakes, steering, flight controls or flaps/slats movement before engine start.

Yes you do need brakes and steering prior to engine start. Flight controls not so much.

CALTECH · Sat Dec 29, 2018 4:46 am

Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

Are you sure ?

http://www.smartcockpit.com/docs/A330_F ... Pilots.pdf

Page 39 of 210

A330 hydraulic system
4.3
General
• Three fully independent systems : Green, Blue, Yellow
(nominal pressure at 3000 psi).
• Normal operation :
They are managed by the HSMU (Hydraulic System
Monitoring Unit) which ensures all autofunctions (electrical
pumps, RAT, monitoring, etc) ; manual override is
available on the overhead panel.
- one handpump on the Yellow system for cargo doors
operation when no electrical power is available.
• Abnormal operation :
ELEC
OVHT
GREEN
3000
LO AIR
PRESS
OVHT
1
ELEC
BLUE
3000
1
ELEC
YELLOW
3000
2
PTU
GREEN
2

chimborazo · Sat Dec 29, 2018 8:16 pm

Hmmm. I don’t buy that about push, stop, brakes, engine start. On pretty much every flight I’ve been on, one or more engines is started during the push back IIRC- across all types. Why would you need brakes when connected to the tug? In any case, the brake pressure accumulator would (should?) be charged so you would have some brakes.

chimborazo · Sat Dec 29, 2018 8:19 pm

And the tug/truck doesn’t “assist” in the push back: it DOES the push back.

I was sat at Heathrow earlier and the engines were definitely running before steering lock pin was removed on the A320s I saw

Apprentice · Sun Dec 30, 2018 8:56 am

Hi Chimborazo, My English is not as good as your, sorry is I write something wrong.
Even if a/c start 1 or both engine, during push back, You will need brakes to hold plane when You need to disconnect the tug, in fact, You ask Crew for brakes ( Push Back completed, Parking Brakes set please) before disconnecting tug. And only with tow bar disconnect, You remove Steering Pin.
We use different criteria:
Tug push or tow a/c, but to complete a process, you need:
Tow bar
Steering by-pass pin
Shocks in - out.in
Head set
A qualified man up, at a/c pilot seated
a qualified man down, guiding all te operations

Rgds

Apprentice · Sun Dec 30, 2018 9:05 am

[Quite/]Maybe I'm misunderstanding you but you don't need brakes, steering, flight controls or flaps/slats movement before engine start.[/quote]
Yes you do need brakes and steering prior to engine start. Flight controls not so much.[/unquotted]

Hi: In order to perform Push Back, Brakes available are mandatories
As soon as You finish it, steering control is necessary
Flight Controls Check and Flap -Slats movement to TO Position, are MANDATORY before arriving to Landing Strip. Each company got it’s own way, must do as a soon as possible.

Rgds

Apprentice · Sun Dec 30, 2018 9:15 am

[Quote]//. Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another. [Unquotted]//
Hi.
You may not transfer Hydraulic Fluid from two systems, but You have a push button to pressurize System 2 is there is Pressure in System 3 and System 1 If on nbr 2.
When ready to push back, Electric Pumps for System #3 are selected on (System 3 pressurize Brakes and Steering, and, if needed, “Pressure Transfer Pumps”will pressurize, in order, System 2 and System 1
Rgds

Apprentice · Sun Dec 30, 2018 9:15 am

[Quote]//. Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another. [Unquotted]//
Hi.
You may not transfer Hydraulic Fluid from two systems, but You have a push button to pressurize System 2 is there is Pressure in System 3 and System 1 If on nbr 2.
When ready to push back, Electric Pumps for System #3 are selected on (System 3 pressurize Brakes and Steering, and, if needed, “Pressure Transfer Pumps”will pressurize, in order, System 2 and System 1
Rgds

stratclub · Sun Dec 30, 2018 9:32 am

That is correct. A transfer pump does not transfer fluid from one system to another. What can transfer fluid from one system to another are actuators that use more than one system for hydraulic power such as the brakes on a 747.

wiggy · Sun Dec 30, 2018 9:52 am

I hear it a few time when flying jetstar

Apprentice · Mon Dec 31, 2018 12:49 am

Hi: Qty of hydraulic that “pass” from one system to another are strictly regulated. Normally it should be “0”, with age and seals semi- worn, they increase. It is not an special item and it is not frequently complained, but if it, there are strict regulations about in AMM
Rgds

Starlionblue · Tue Jan 01, 2019 5:28 am

CALTECH wrote:
Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

Are you sure ?

http://www.smartcockpit.com/docs/A330_F ... Pilots.pdf

Page 39 of 210

A330 hydraulic system
4.3
General
• Three fully independent systems : Green, Blue, Yellow
(nominal pressure at 3000 psi).
• Normal operation :
They are managed by the HSMU (Hydraulic System
Monitoring Unit) which ensures all autofunctions (electrical
pumps, RAT, monitoring, etc) ; manual override is
available on the overhead panel.
- one handpump on the Yellow system for cargo doors
operation when no electrical power is available.
• Abnormal operation :
ELEC
OVHT
GREEN
3000
LO AIR
PRESS
OVHT
1
ELEC
BLUE
3000
1
ELEC
YELLOW
3000
2
PTU
GREEN
2

Yes, I'm sure there is no PTU on the A330. The term Power Transfer Unit and the abbreviation PTU do not show up in the A330 FCOM at all. There is no PTU in evidence in the system diagrams and descriptions, or in any of the procedures.

Where did you find that reference?

Apprentice wrote:
//. Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another. [Unquotted]//
Hi.
You may not transfer Hydraulic Fluid from two systems, but You have a push button to pressurize System 2 is there is Pressure in System 3 and System 1 If on nbr 2.
When ready to push back, Electric Pumps for System #3 are selected on (System 3 pressurize Brakes and Steering, and, if needed, “Pressure Transfer Pumps”will pressurize, in order, System 2 and System 1
Rgds

Electric pumps are not selected on before pushback as part of normal procedure on the A330. And there are no "pressure transfer pumps".

Note I said "transfer power", like the PTU on the A320, not "transfer fluid".

greg85 wrote:
Starlionblue wrote:
Caryjack wrote:
I heard this dog on a Delta A-330 (SEA-AMS). It barked from the start of the outbound taxi until the takeoff roll. I'd guess that the delayed barking occurred because the larger airliner required extra time for the pump to equalize pressure. It was funny to me and I quietly laughed most of the way out.

http://www.askthepilot.com/questionansw ... us-noises/

From the link: "This pertains to twin-engine Airbus models: the A320 series (includes the subvariants A319 and A321) and the larger A330."

Thanks,
Cary

I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

greg85 wrote:
You’ll also find that the barking dog is much faster and louder after a single engine taxi in. This is because of the pressure difference between the green and yellow hydraulic systems. After a single engine taxi in the green system slowly loses pressure as the engine winds down, while the yellow goes quickly to zero after the yellow electric pump is switched off.

I think you mean the Yellow system Engine Driven Pump.

No, I mean yellow electric pump. I’m talking about taxi with engine number 1 only.

I stand corrected. I get what you meant now.

Starlionblue · Tue Jan 01, 2019 9:54 am

CALTECH wrote:
Starlionblue wrote:
I don't know what you heard but it wasn't a PTU since the A330 does not have one. There are 3 hydraulic systems and no way to transfer power from one to another.

(Yes, Mr. Smith is wrong on that one.)

Are you sure ?

http://www.smartcockpit.com/docs/A330_F ... Pilots.pdf

Page 39 of 210

A330 hydraulic system
4.3
General
• Three fully independent systems : Green, Blue, Yellow
(nominal pressure at 3000 psi).
• Normal operation :
They are managed by the HSMU (Hydraulic System
Monitoring Unit) which ensures all autofunctions (electrical
pumps, RAT, monitoring, etc) ; manual override is
available on the overhead panel.
- one handpump on the Yellow system for cargo doors
operation when no electrical power is available.
• Abnormal operation :
ELEC
OVHT
GREEN
3000
LO AIR
PRESS
OVHT
1
ELEC
BLUE
3000
1
ELEC
YELLOW
3000
2
PTU
GREEN
2

Ah. I saw the link now. The picture of the ECAM HYD page does indeed show a PTU. However, the same page in the FCOM does not show anything in that location.

I get the feeling there's a misprint in that presentation. Either that or the Ghost PTU (GPTU) existed at some point during the design or in initial frames but was later deleted.

WPvsMW · Wed Jan 02, 2019 1:13 am

Perhaps an option that operators could select, FCOMs and marketing brochures being apples and oranges.

Starlionblue · Wed Jan 02, 2019 2:10 am

WPvsMW wrote:
Perhaps an option that operators could select, FCOMs and marketing brochures being apples and oranges.

True.

However, I can't understand why you would need a PTU given the architecture of the hydraulics.

Apprentice · Thu Jan 03, 2019 2:47 am

Starlionblue wrote:
WPvsMW wrote:
Perhaps an option that operators could select, FCOMs and marketing brochures being apples and oranges.

True.

However, I can't understand why you would need a PTU given the architecture of the hydraulics.

Mostly for Push Back and for Maintenance:(A330/340) and of course, for emergency.

-2 ea electric pump pressurize System 3 only
- 1 Hydraulic Pump, use system 3 pressure as energy source and move a Pump that raise pressure on system nbr 1
- same that above, raise pressure in system # 1

Rgds

Apprentice · Thu Jan 03, 2019 3:10 am

Starlionblue wrote:
WPvsMW wrote:
Perhaps an option that operators could select, FCOMs and marketing brochures being apples and oranges.

True.

However, I can't understand why you would need a PTU given the architecture of the hydraulics.

Mostly for Push Back and for Maintenance:(A330/340) and of course, for emergency.

-2 ea electric pump pressurize System 3 only
- 1 Hydraulic Pump, use system 3 pressure as energy source and move a Pump that raise pressure on system nbr 1
- same that above, raise pressure in system # 1

Rgds

Starlionblue · Thu Jan 03, 2019 3:11 am

Apprentice wrote:
Starlionblue wrote:
WPvsMW wrote:
Perhaps an option that operators could select, FCOMs and marketing brochures being apples and oranges.

True.

However, I can't understand why you would need a PTU given the architecture of the hydraulics.

Mostly for Push Back and for Maintenance:(A330/340) and of course, for emergency.

-2 ea electric pump pressurize System 3 only
- 1 Hydraulic Pump, use system 3 pressure as energy source and move a Pump that raise pressure on system nbr 1
- same that above, raise pressure in system # 1

Rgds

I get that a PTU would increase redundancy, but I still don't see a compelling case for it.

At pushback, with either engine running the green system is pressurised, so you have brakes. Once the left engine is running you also have alternate braking powered by the blue system. So you're fine taxiing on the left engine only.

In an emergency, the plane can be controlled with any two hydraulic systems failed.

For reference, engine one has pumps for the blue and green system, while engine two has pumps for the yellow and green system. The RAT powers the green system.

Apprentice · Thu Jan 03, 2019 8:46 am

Hi: They called it: “Redundancy” and it is considered necessary, specially for ETOP flights. Should one engine fails, You loose one or 2 systems, provide no PTU.
Same on ground, if for any Mx check You need to start eng, big lost of time. (Note that Hyd Carts, for A330, whith 3 ea independent high pressure high flow pumps do not abund.

Rgds

Starlionblue · Thu Jan 03, 2019 5:18 pm

Apprentice wrote:
Hi: They called it: “Redundancy” and it is considered necessary, specially for ETOP flights. Should one engine fails, You loose one or 2 systems, provide no PTU.
Same on ground, if for any Mx check You need to start eng, big lost of time. (Note that Hyd Carts, for A330, whith 3 ea independent high pressure high flow pumps do not abund.

Rgds

It isn't considered necessary for ETOPS. We do ETOPS every day on the A330 without a PTU.

Apprentice · Thu Jan 03, 2019 7:00 pm

Rgds[/quote]

It isn't considered necessary for ETOPS. We do ETOPS every day on the A330 without a PTU.[/quote]

Hello: Long time I did not touch a A-330, but I was not sure that an emergency Item will be allowed to be inop as per MEL. So I look in an a FAA’s MMEL and did not find nothing related to Pressure Transfer Unit (PTU). As per This MMEL You may have inop an Engine Driven Pumps, & Electric Pumps, but I found nothing about PTU. (By the way: PTU are our “barking Dogs”since, as explained, they use Hydraulic Pressure in “Motor” side and produce Hyd power in Hyd ).
Some one correct me with last MMEL?

Many Thanks

Apprentice · Thu Jan 03, 2019 7:06 pm

Hello Jetwet1:
One image is better that...
Note that new PTU as new pump, will make less noise than an older one.

https://m.youtube.com/watch?v=9ffJgk1-tCA

Rgds

Apprentice · Thu Jan 03, 2019 7:10 pm

(Sorry...) in this video, Left side is the “Hydraulic Motor” that uses energy from other system pressurized.
Right side is the pump. (No big Flow, but enough for emergency items)

Rgds

Apprentice · Thu Jan 03, 2019 7:27 pm

Hello:

Quotte//: get that a PTU would increase redundancy, but I still don't see a compelling case for it.
At pushback, with either engine running the green system is pressurised, so you have brakes. Once the left engine is running you also have alternate braking powered by the blue system. So you're fine taxiing on the left engine only.
In an emergency, the plane can be controlled with any two hydraulic systems failed.
For reference, engine one has pumps for the blue and green system, while engine two has pumps for the yellow and green system. The RAT powers the green system.// Unquotted

If Green System is inop. You have not NWS. So it will be difficult to control on ground.
Also, You do not have pressure for Move down LG, so Yo will need to lower it manually. And main doors will remain open. No Spoiler 1
If You lost eng #2, two system out of three are lost. Making difficult to have full Authority over FC, and...

Rgds

Starlionblue · Fri Jan 04, 2019 3:39 am

Starlionblue wrote:
It isn't considered necessary for ETOPS. We do ETOPS every day on the A330 without a PTU.

Apprentice wrote:
Hello: Long time I did not touch a A-330, but I was not sure that an emergency Item will be allowed to be inop as per MEL. So I look in an a FAA’s MMEL and did not find nothing related to Pressure Transfer Unit (PTU). As per This MMEL You may have inop an Engine Driven Pumps, & Electric Pumps, but I found nothing about PTU. (By the way: PTU are our “barking Dogs”since, as explained, they use Hydraulic Pressure in “Motor” side and produce Hyd power in Hyd ).
Some one correct me with last MMEL?

Many Thanks

Since there's no PTU, it won't be in the MEL.

Our MEL says all 4 engine driven hydraulic pumps must be operative. However, any of the 3 electric pumps may be inop for 10 days.

Apprentice wrote:
Hello:

Quotte//: get that a PTU would increase redundancy, but I still don't see a compelling case for it.
At pushback, with either engine running the green system is pressurised, so you have brakes. Once the left engine is running you also have alternate braking powered by the blue system. So you're fine taxiing on the left engine only.
In an emergency, the plane can be controlled with any two hydraulic systems failed.
For reference, engine one has pumps for the blue and green system, while engine two has pumps for the yellow and green system. The RAT powers the green system.// Unquotted

If Green System is inop. You have not NWS. So it will be difficult to control on ground.
Also, You do not have pressure for Move down LG, so Yo will need to lower it manually. And main doors will remain open. No Spoiler 1
If You lost eng #2, two system out of three are lost. Making difficult to have full Authority over FC, and...

Rgds

As you say if the green system is inop you don't have NWS. But clearly if any of the hydraulic systems is inop that's a a no-go item.

If you lose the green system in the air, you'd extend the gear by gravity, brake with alternate braking, and have to be towed off the runway because you can't steer.

If you lose engine 2, you lose the yellow system only, not two systems out of three. The green system is still powered by an EDP in engine 1. In the same way, if you lose engine one, you lose the blue system only.

Apprentice · Fri Jan 04, 2019 4:24 am

A-320, a PTU push button located between yellow and blue system.: http://www.smartcockpit.com/docs/A320-O ... _Panel.pdf
4 ea posts above there is a link to a photo in Main LG wheel well.
So, You have a real PTU image and a Pushbutton that control it, (A-320, as Post’s title But, is Station
Blue said that “there is not PTU” up to him. I do not go into fighting

By the way, MEL is a list of items that may be deferred for flight. No -Go ítems do not use to be there as per obvious reasons.
So, for instance, You will not find listed a “Lower Rudder Surface” since it is no-go

Rgds

Starlionblue · Fri Jan 04, 2019 4:48 am

Apprentice wrote:
A-320, a PTU push button located between yellow and blue system.: http://www.smartcockpit.com/docs/A320-O ... _Panel.pdf
4 ea posts above there is a link to a photo in Main LG wheel well.
So, You have a real PTU image and a Pushbutton that control it, (A-320, as Post’s title But, is Station
Blue said that “there is not PTU” up to him. I do not go into fighting

By the way, MEL is a list of items that may be deferred for flight. No -Go ítems do not use to be there as per obvious reasons.
So, for instance, You will not find listed a “Lower Rudder Surface” since it is no-go

Rgds

Sorry for being unclear. CALTECH showed a slide above showing a PTU on the A330, so I was talking about the A330 and the fact it does not need a PTU.

Apprentice · Fri Jan 04, 2019 11:24 am

Hello: As Caltech used to be carefully in his posts, I pay a check to Airbus A330’s “ Flight Deck and System briefing for pilots”, page 4.2. ““http://www.smartcockpit.com/docs/A330_Flight_Deck_and_Systems_Briefing_For_Pilots.pdf“ and, Airbus included and schematic with.. a PTU !!!. As A330 does not need PTU, I may suppose that Airbus included it to get $. And gave a false reason, “ in case of full hydraulic power lost, RAT will power Grren System , And PTU , using Green power, may pressurize Yellow System . Still difficult times but with less heavy FC.”

Rgds

Apprentice · Fri Jan 04, 2019 11:38 am

Hi, Sorry again, reading same “FDASBFP” in “Abnormal Proccedures”, Airbus also consider this one:

“- in the event of engine 2 failure, the Yellow electrical pump runs automatically when flaps are not retracted”, thus pressurizing Yellow and Green System, using PTU. (See schematic no same page 4.2) .
Sorry Airbus, it looks that, beside Mx, there are cases when pump is needed....

Rgds

strfyr51 · Fri Jan 04, 2019 11:52 am

jetwet1 wrote:
I've spent the last week flying in and out of LHR on (sadly) BA's 320.

The first one was (judging from the cabin) an older 320 and the dog was barking like a pitbull on crack, the next couple were on newer aircraft (new style cabin, mood lighting etc) and no dog.

I did do a search, but couldn't find a clear answer (using my phone so searches are brutal), did Airbus change something to reduce the "barking" on later ceo's ?

On the A320/A319 series you can hear the PTU working when 1 engine is used on single engine Taxi when setting the Flaps. I don't think the PTU is even deferrable so that's the Pilot's check to insure it even works. (if I remember correctly)

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