Even a light coating of dry snow can be dangerous.
Deicing is costly, time-consuming and 100% necessary. Wings are amazing pieces of engineering. A wing is built to precise specifications. The exact curvature of the wing produces a set amount of lift that is then used to calculate takeoff distances, max takeoff weight, and climb performance. Any dent or debris on the wing can cause the wing to be way less efficient.
Snow and ice on the wings disrupts the flow of the air. In many cases significantly. A wing with any snow or ice or debris is called a contaminated wing. Air Florida flight 90 crashed into the Potomac River due to a contaminated wing similar to the aircraft in this video.
Why was this takeoff so dangerous?
Snow and ice on the wings disrupts the flow of the air. A wing with any snow or ice or debris is called a contaminated wing. Even a thin coating of ice can be deadly. Air Florida flight 90 crashed into the Potomac River due to a contaminated wing similar to the aircraft in this video. 78 people died because of that mistake.
In the video, you’ll see the snow rapidly blow off the wing as it accelerates. However, it appears that ice and snow remains on the wing even as the aircraft becomes airborne. At this point, the pilots and passenger are now part of a test flight. The Airbus A320 is a different jet than spec. It has a new untested stall speed, untested climb characteristics. Even the mechanical flaps and slats have never been retracted with that exact set of ice and snow characteristics. What those pilots did was extremely dumb. Even though most of the snow blew off, you can still see significant spots of ice that remain on the wing. Airliners do have systems that allow them to fly through icing conditions (up to moderate) but they are primarily designed to prevent ice buildup, not remove the existing ice and snow seen in the video. If I was a passenger onboard, I would’ve created such a disruption that they would’ve been force to go back to the gate. Even if I ended up in jail, it is better than being dead.
Bottom line? Deice your jet before you go fly. Full stop.