What is the PTU (Power Transfer Unit)?

Ever wondered why you hear dogs barking whenever you're onboard an A320, especially during engine start-ups, like the one at 1:06 - 1:11, but you're so sure that there are no dogs onboard?

Now, here's why! Modern airliner jets have independent hydraulic systems on both sides of the aircraft that are powered by engine-driven pumps. When, for example in this case, only one engine is turned on, the hydraulics are turned on for only one side of the aircraft. A device hence transfers hydraulic power to the other side of the aircraft where the hydraulics are still unpowered, as the engine is still turned off. This device, on the A320, makes a sound resembling barking dogs, and it's called the PTU, or Power Transfer Unit.

Therefore, the PTU plays an important role in the event of a hydraulic failure on one side of the aircraft, allowing both sides of the aircraft to receive hydraulic power and thus positive control.

Category:

Science & Technology

Tags:

• PTU
• power
• transfer
• unit
• A320
• engine
• start-up
• jetstar
• KLIA

[samueltanjk]

what camera you use?

[greatflyer96]

@samueltanjk Samsung HMX-U10.

[samueltanjk]

@greatflyer96 great sound recording!

[adamallred58]

This is one of my favorite moments on any trip via airplane (right before the takeoff and during takeoff.) I also like the moment of landing the plane.

[jbjetairways]

clears my doubt ;)

[videoguy1motion]

Thanks for the info!

[greatflyer96]

@transfer8 Thanks!