The Operating Environment and Aircraft Performance

 

Icing in Aircraft Performance

Icing is, perhaps, the most dangerous thing that can happen to an airplane environmentally wise. Icing will not only change the aerodynamic shape of the airfoils in the airplane but will also increase the aircraft's weight.

Icing can adhere to the airplane's structure very easily when flying under icing conditions. These conditions include freezing temperatures (0 degrees Celsius) and flying in visible moisture. Ice will attach to each airfoil quickly and change its shape. When the shape changes the chord line will also change, making the angle of attack change. If a pilot doesn't realize that the angle of attack has changed he may suffer from an unexpected stall, or even a spin, with catastrophic consequences.

With ice, the airplane's weight will also increase. If we refer to the 4 forces of flight when weight increases lift needs to also increase to maintain straight and level flight. The pilot will need to increase the angle of attack, increasing stall speed to a dangerous point.

Also, icing will increase the airplane's drag. That is why is really important that when a pilot recognizes icing in the airplane's structure he should take some actions to ensure the safety of the flight. Upon landing, the pilot should avoid using flaps unless strictly necessary, as flaps will increase even more the drag of the airplane, making landing a dangerous task. Faster airspeeds should also be used to overcome the increased weight and drag of the airplane.

Technology has produced several anti-icing and de-icing products to help this dangerous situation. Refer to PHAK for further information on these products and how they help to produce fewer accidents, especially during the winter season.

References

U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service. (2022). Pilot's Handbook of Aeronautical Knowledge.

Casto, D. (2021, February 4). De-icing protocols for flight operations. DTN. Retrieved August 17, 2022, from https://www.dtn.com/de-icing-protocols-for-flight-operations/

Discoveries on ice. Flight Safety Foundation. (2018, February 27). Retrieved August 17, 2022, from https://flightsafety.org/asw-article/discoveries-on-ice/