By Kim Rahn
Staff Reporter

Snow is the No.1 enemy for air travelers. The nation had unusually heavy snow this week, delaying many flights and forcing travelers to stay at airports for long periods of time.

On Monday, when heavy snow warnings were issued in Seoul and Gyeonggi Province, 125 flights, out of the total 154 scheduled to depart before 3:30 p.m., were delayed for more than an hour. Also, on Tuesday, 87 flights out of 147 were delayed as of 3 p.m.

The delay was, however, not because of snow removing work on runways, but rather because of deicing work on aircrafts.

Deicing is an operation removing snow, ice or frost stuck to aircrafts using special liquid.

According to international aircraft operation rules, frost, ice and snow must be removed from an aircraft's wings, nose and other important parts before a plane departs. The U.S. Federal Aviation Administration also disallows flights from departing if the plane's exterior is frozen.

Such rules are strictly enforced, as deicing is essential for safe operation in winter. If frozen snow is attached on the surface of an aircraft, the plane may not get enough lift as it gets heavier and the flow of air may become irregular. Planes may also fail to take off or even crash.

In January 1982, an Air Florida plane carrying 79 passengers and crew members departed from Ronald Reagan Washington National Airport without sufficient deicing. It failed to take off properly and fell, crashing into a bridge over the Potomac River, killing 74 people.

Planes move to the deicing operation facilities after taking passengers, as they need to remove snow that was piled on during boarding. As the deciding work is conducted just before takeoff and takes 20 to 30 minutes, flights are inevitably delayed.

To remove ice and snow, deicing liquid is sprayed on aircrafts and white anti-icing liquid is put again to prevent re-freezing. As the deicing liquid is classified as a pollutant, the operation should be conducted at designated places ― there are two deicing facilities at Incheon International Airport.

The operation cost differs according to the type of aircraft and the time spent for the work ― on average, it costs 700,000 to 800,000 won per plane.

Upon deicing, snow should not affect airplanes as they fly above clouds.

rahnita@koreatimes.co.kr