The Airbus A320 is one of the most popular narrowbody jets ever to fly. With more than 12,480 built and another 7,000+ orders (as of early 2026), there is a high likelihood that you’ve either flown on one before or will fly on one soon. It’s a nice ride.
The jet is wider than the Boeing 737. For pilots, the plane is also fly-by-wire, has a side stick instead of a yoke, and even a fold-out tray table at each crew position. There is one very peculiar thing about the jet. Before takeoff, when the engines are starting, and after landing (typically at the gate), the jet makes an odd barking noise. Why is that?
Yep, the Airbus A320 sounds like a barking dog after its lands
For the first-time traveler, they might think that their jet is carrying a pack of race dogs in the cargo compartment below. The video above from DAR 4K does a nice job of capturing the noise. We can assure you. It’s not a dog (or pack of them). It’s actually a noise from the PTU, or power transfer unit.
Here’s your answer: The Power Transfer Unit is Why The Airbus A320 Sounds Like A Barking Dog
The PTU transfers power between hydraulic units. In the A320, there are actually three hydraulic systems. Each engine powers two hydraulic systems, with a third system powered by an electric backup pump.
The PTU provides hydraulic power across the systems. Hydraulics are used in flight to power the control surfaces, landing gear deployment and retraction, nose wheel steering, the ground braking system, and the movement of the flaps and slats. The system’s power is shared, but fluid is not. This setup ensures that even with one engine off, you still have full hydraulics available.
The reason that the Airbus A320 sounds like a barking dog when departing the gate is that typically, only one system is running. Upon arrival, one engine is typically shut down. That means the system is using the PTU to keep the entire hydraulic system pressurized.
It’s a great system that works and ensures that pilots have access to all controls at all times. But it can be a bit annoying, particularly if you’re sitting in rows 15-20.
EDITOR’S NOTE: This article was originally published on 1 May 2022, but was updated in February 2026 with the latest information regarding A320 deliveries and orders.
