The A320 series is known for having a distinct whine, essentially caused by the pressure equalisation vents for the fuel tanks, which are open to the external airflow.
Why do Airbus planes make strange noises?
The reason that the noise comes and goes is that the PTU is only operational when the hydraulic pressure of the A320 or A330 drops below a pre-defined level. And due to the fact that pressure can fluctuate, the noise will sometimes continue even after both engines are fully operational.
Why do jet engines sound different?
Jet engines produce noise in different ways, but mainly it comes from the high-speed exhaust stream that leaves the nozzle at the rear of the engine. And planes are loudest when they move slowly, such as at takeoff or at landing. … The turbulence produced from this instability becomes the roar of the engine.
Why is Airbus so loud?
The source of certain Airbus planes’ characteristic barking noise is a component known as the Power Transfer Unit (PTU). This part is an element of the aircraft’s hydraulic systems, and it facilitates the switching of power from one system to another in the event of a failure.
What is the sawing sound on an Airbus?
A: I suspect you are referring to the Airbus A320 family when the Power Transfer Unit (PTU) activates during taxi in. The PTU has been described as a “dog barking,” “a NASCAR tire lug gun” or “sawing.” The noise is the normal sound the PTU makes when it powers one of the hydraulic systems.
Why do Jets Buzz on takeoff?
When a plane takes off, it (often) has its thrust levels set high. As such, the blades in the fan of the engine are moving faster than the speed of sound. As a result, a buzzing noise occurs.
Why are planes so loud at night?
During the day, when the air is warmer than the ground, noise energy from an airplane staying in the air, so while you can still hear it, it seems quieter. Conversely, at night, when the ground is warmer than the air, the noise is drawn down, making it seem louder.
Why do turbofans buzz?
The advent of the high-bypass-ratio turbofan engine led to a significant step-change reduction in noise from jet engines, principally due to lower levels of jet noise. … These tones are known colloquially as the “buzz-saw” noise.
Why are some planes louder than others?
Some aircraft make more noise than others because of the type of engines they use. Newer aircraft and aircraft engines typically are quieter as a result of improved designs and technology. … Additionally, where you are standing in reference to the aircraft and the aircraft’s direction of travel matters.
Why are planes not loud inside?
First, the cabin is quieter because the fuselage walls are designed to limit the transmission of sound from the engines. Second, on most commercial aircraft, the engines are suspended beneath the wings, which block the noise from the engines before it can strike the fuselage.
Can you hear PTU in cockpit?
The PTU is located near the main landing gear, and that’s why passengers can hear the noise seemingly coming from mid-way down the aisle, under the floor. … “We don’t actually hear this noise from the flight deck but, like the rest of the public, we do hear it if we are traveling in the cabin as a passenger.
What is the dog barking sound on an airplane?
These twin-engine models feature a device called the power transfer unit (PTU), which, in layman’s terms, helps to conserve fuel. It also is designed to power the hydraulic systems in the aircraft. As the PTU cycles on and off when pressure fluctuates, it generates a loud, recurrent sound like that of a dog barking.
How loud is an A320?
Similarly, the 737 is 0.9 decibels louder than the A320, or about 10% “louder”. Fascinating stuff.
The Silence of Airplanes.
|Aircraft||A319, A320, B767-300, MD-90|
What is the PTU on a plane?
In aviation, a power transfer unit (PTU) is a device that transfers hydraulic power from one of an aircraft’s hydraulic systems to another in the event that second system has failed or been turned off. The PTU is used when, for example, there is right hydraulic system pressure but no left hydraulic system pressure.
What is the loud noise after a plane lands?
More roars and the barking dog sound returns. After the plane lands, the pilot will deploy panels that come out of the wings to keep aircraft on the ground and to help slow it down. The engines will also be switched to reverse thrust – signally and loud, but completely normal roar.
Why do planes howl?
This is caused by air rushing across the under-surface of the wing, where there are Fuel Over Pressure Protector (FOPP) cavities. This generates noise, in the same way as blowing air over the mouth of a bottle. Every A320 series aircraft emits a signature howling noise while approaching to land.