You might have noticed that on some of your plane rides, the plane suddenly vibrates as it lifts off, and then the vibration suddenly disappears. This vibration causes loose items to shake. It sounds as though the plane may break mid-air. As this happens, it can be worrisome for some passengers, especially for first-timers. But is there anything to worry about? Well, this vibration you hear is somewhat normal.
The Shift from Landing Gear to Wings
The first thing to know is that when a plane takes off, its weight shifts from the landing gears to the wings and the rest of the airframe. This shift causes the interior panels to shudder and vibrate. At the same time, the engines are running at very high speeds, nearly 90% of their capacity, and the plane itself is moving fast. All these factors contribute to some level of vibration.
The Role of Tires and Brakes
Another reason for the rattling and vibrations is the tires. If you notice that the rattling stops after liftoff, it’s usually because of a vibrating tire sending vibrations through the airframe. This can cause interior panels that are a bit loose to rattle. On most airliners, the brake system applies the main wheel brakes for a moment after takeoff to prevent the usual spin-down vibrations during retraction. Nosewheels usually use a friction brake for the same purpose. So, if the wheel is shaking, it will stop as soon as the plane is airborne.
Airliner wheel assemblies are usually balanced vertically, not dynamically like car tires. This means you can have a vibration mode that kicks in at a certain tire RPM. Once the plane lifts off, the brakes tap the wheels to stop them, and the vibration stops.
The Impact of Runway Material
Runways at major airports are built to handle a lot of action. They’re constructed using durable materials like concrete and asphalt. The choice of material depends on the type of aircraft using the runway and local conditions. Concrete is generally used at most commercial airports because it’s more durable and lasts longer.
When planes take off, their tires roll over expansion gaps in the concrete slabs that make up the runway. These gaps allow the concrete to expand or contract depending on the temperature. A flexible sealant is used in these gaps to prevent ice damage. Rolling over these gaps usually causes the first vibrations and noise you experience during takeoff.
So, I hope this eases your “worry” or “fear” when you hear a vibrating sound during take off. Don’t worry; the plane won’t break apart. Just trust your plane and the pilots. It’s normal for planes to vibrate for a very short while during take off.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
