Airbus sound question

[great cornholio]

It's a fat lady in corduroy pants walking around.

To me it sounds a bit fast for walking, but sounds more like runnin towards her next twinkie.

 

[NEDude]

If you turn on the yellow electric pump you never have that noise..

I am amazed at how few airlines seem to not turn it on during single engine taxi. I was riding in the back of a United A319 a few weeks ago during a long taxi in ORD and the PTU ran for 40 minutes before they started the other engine.

 

[flyn96]

Heard a pax say how it sounded like a barking dog down in cargo and how the airline was so bad that they couldn't even treat a dog with respect. Pretty funny stuff.

 

[Bringupthebird]

I am amazed at how few airlines seem to not turn it on during single engine taxi. I was riding in the back of a United A319 a few weeks ago during a long taxi in ORD and the PTU ran for 40 minutes before they started the other engine.

If you're taxiing on No. 2 then running the electric pump doesn't do any good (eng2 is driving the yellow pump anyhow). If you're taxiing on No.1, you have the yellow electric pump operating in the unlikely event you shuck the green pump. Moral of the story: SE taxi on eng 1 only (if you can ). Also the electric pump can overheat.


I had a passenger get off the airplane saying "I thought you'd never git that motor started with that dead batt'ry. She just cranked and cranked and cranked."

 

[critterair2]

wow a thread that made it through a whole page and no hijack...YET

 

[kf4amu]

If its a pump, why does it turn on and off so quickly? I'd expect those conditions for PTU operation to be pretty static and unchanging from second to second.

 

[Cardinal]

It's not so much a pump as two hydraulic motors bolted to each other. And like everything else is electronically controlled. When it senses a differential of 500 psi between systems it will "run" (allow one hydraulic motor to turn the other) in order to bring the low side up to 3000psi, then stop until the system bleeds down and the differential agains reaches the 500 psi threshold for activation.

The system will also run during periods of high demand when one system's pressure is pulled down, i.e., gear retraction. Why build each hydraulic system to be up to it's task? Better to do it the socialist way, a team effort, with each system helping out when times get tough. I am the green system, and I am my brother's keeper.

 

[CA1900]

The system will also run during periods of high demand when one system's pressure is pulled down, i.e., gear retraction. Why build each hydraulic system to be up to it's task? Better to do it the socialist way, a team effort, with each system helping out when times get tough. I am the green system, and I am my brother's keeper.

:laugh:

Well-done.

 

[Vingus]

Jetblue SOP is to turn on the yellow pump during single engine ops to keep it quiet. We used to have a SOP that shut the PTU off on engine shutdown which would keep it quiet at the gate. That SOP went away when too many guys forgot to turn it back on when the left the cockpit. It was a good idea, but as usual, a few dummies ruined it for everyone.

 

[lowtimedriver]

It's a fly-by-wire baggage handler.

 

[BLUE BAYOU]

I still turn the PTU off at shutdown until at least a cargo door is opened (which actuates the yellow hydraulic pump). This usually resolves the barking dog issue which is at its worst at engine shutdown at the gate.

 

[ACL65PILOT]

Most big jets have them. That is why on the 767/757 we start the left engine first. That way it will not go on.

 

[Ralph Cramden]

Fifi plays both ways. It's a French tradition! PTU can be powered by yellow or green (that's L & R to the non french speaking), and powers the lower pressure side. Blue (center to non french speaking) is lonely, only plays with itself (the rat is it's backup).

 

[PreContact]

Just say the words RED RUM, that's what it sounds like to me!~

 

[Guppiedriver]

If you turn on the yellow electric pump you never have that noise..

The high pitched whine of the yellow electric pump is just as annoying as the PTU.