Why can snow ice drop aircraft?

A NASA expert said that ice is a contributing factor to 9.5% of aircraft accidents.

Snow ice attack

Whether flying in the sky or parked on the ground, aircraft can be attacked by snow and ice.

When the plane is parked on the tarmac, snowfall will form a layer on the top of the wing and tail of the plane, like you leave your car overnight outside.

Snowfall on the flaps of aircraft.

In addition, snow ice can be closed on planes as it flies through the cumulative clouds. Everyone knows that water will freeze if the temperature drops to 0 degrees C. However, purified water in the atmosphere can still exist in liquid form even if the temperature falls below 0 degrees Celsius if not met. Suitable face to freeze.

Thomas Ratvasky, an engineer at NASA's Glenn Research Center, said he and his colleagues found that in the winter there were many clouds formed from small water particles despite temperatures of -40 degrees Celsius.

When the plane passes through the cloud, small droplets of water will instantly turn into ice and form into the shell because it is a suitable surface to freeze.

Threat "thin like sandpaper"

In December 1985, Arrow Air's flight 1285 returned American soldiers from Egypt to their home base in distress. As soon as it took off at the transit point in Gander (Canada), the DC-8-63CF was stalled and dropped, killing 256 passengers and crew.

After investigating the accident, the Canadian Air Safety Agency (CASB) discovered that the harsh weather conditions that day could create ice on the wing. CASB said that the cause of the crash is likely due to the snow ice on the wings and the upper surface of the wing. Before takeoff, the DC-8-63CF was not processed to melt the snow on the surface.

The wings and tail are the lift parts of the aircraft. The lift force of the aircraft wing depends on the relative angle (wind pickup angle) that air flow creates with the wing. The larger this angle, the higher the plane can climb.

However, snow-covered ice will change the surface smoothness so that the aircraft wings do not reach the maximum lift, reducing the winding angle.

As long as this surface loses its original smoothness, the aerodynamic lift of the wing will decrease and friction increases.

Experts are removing snow on the aircraft case.

The snow and ice layer is just as thin and rough as a piece of sandpaper, which is enough to reduce the lifting force by 30% and increase the resistance by 40%.

In the event that the airflow cannot surround the upper surface, the aircraft will be stalled, losing its balance at high speed. This can cause the aircraft to slow down suddenly and break down uncontrollably.

Ratvasky said ice is a contributing factor to 9.5 percent of plane crashes.

Protect the aircraft from the risk of snow and ice

Although many airplanes have flight aids in the snow, in harsh conditions, some methods of dealing with snow and ice have to be used. In it, there are 2 popular methods: removing snow and anti-freezing.

Removing snow is a method that is done when ice is packed into a certain array on the plane. Experts can use mechanical measures such as shaving snow; Use heating equipment or special chemicals to lower the freezing temperature of water.

Aircraft anti-freezing is carried out using a viscous protective layer called an anti-freezing solution. This method is often applied before the aircraft flies in severe snow and ice conditions.