What is turbulence and how did it affect the Singapore Airlines flight?
![What is turbulence and how did it affect the Singapore Airlines flight?](https://nypost.com/wp-content%2Fuploads%2Fsites%2F2%2F2024%2F05%2F211-passengers-18-crew-made-82358897.jpg?quality%3D90%26strip%3Dall)
A stealthy form of turbulence known as clear-air turbulence caused a Singapore Airlines flight to plunge 6,000 feet Tuesday -- leaving a 73-year-old British grandfather dead and more than 30 passengers injured.