While on route from Costa Rica to Colombia, an Avianca Airbus A319 declared an emergency after hitting severe turbulence that injured several of the crewmembers.If you ever needed reminding of why it is always best to have your seatbelt fastened while flying, read what happened on a routine flight over Central America.The incident occurred Thursday morning on the 23rd of January, 2020, when Avianca flight number AV693 was on route from San José-Juan Santamaria International Airport (SJO) to Bogotá-Eldorado Airport (BOG), in Colombia.

The aircraft suddenly dropped

The seven-year-old aircraft, registration number N703AV was cruising at an altitude of 35,000 feet just crossing the Panama, Colombian border when it encountered severe turbulence.

At the time of the incident, the cabin crew was busy serving food and drinks, when all of a sudden the plane dropped 731 meters (2,400 feet), according to aviation website Aerotime.

Passengers later reported that the sudden loss of altitude lasted for several seconds. Realizing that there may be injured people, the captain diverted to Tocumen International Airport (PTY) in Panama City, Panama.

Four people were taken to hospital

Upon landing, all 108 passengers and five crew were checked by airport medical personnel who decided to send three crew members and one passenger to the hospital for further checks. Photos from inside the aircraft show a broken toilet and cracked overhead bins with what appears to be bloodstains.

The Colombian national flag carrier's Airbus A319-132 remained on the ground in Panama pending a technical review. Passengers from the diverted aircraft were put on the next available flight to their final destination at El Dorado International Airport (BOG) in Bogotá, Colombia.

In a statement published by the London Independent newspaper, Avianca said that there was an “abrupt movement of the aircraft” during the flight.

“On arrival, some passengers and crew were referred to airport health authorities,” it said. “As a result of that initial review, a passenger and three crew members are being transferred to the hospital for a detailed medical evaluation.”

What is turbulence?

Every airline passenger has, at some time or another, experienced a phenomenon known as turbulence. While it may feel scary, in most cases there is no cause for alarm.

Turbulence is caused by a sudden change of airflow that can be attributed to several reasons, the most common of which is unstable air in the atmosphere caused by changes in the jet stream winds.

Another type of turbulence is caused by hot air rising that creates thermal turbulence. Wind, being redirected off of mountains and tall buildings can create mechanical turbulence.

Pilots do their best to avoid turbulence by studying weather charts and relying on reports from other aircraft that have experienced choppy air ahead.

While you may be sweating in your seat gripping the armrests, you can rest assured that the pilots know exactly what they are doing and will try to make your flight as comfortable as possible.

As for the Avianca incident, severe turbulence is not so common, but it does happen and is why they tell you to keep your seatbelt fastened.

What is the worst turbulence you have ever experienced? Please let us know in the comments section.