"Ask ATC" Blog

Ice

The winter season can bring a host of challenges to IFR flying, not the least of which is ice.  Whether it is rime, clear or mixed, ice can interrupt airflow around critical control surfaces, altering handling and reducing effectiveness.   Though most pilots understand the concept of icing dangers, how many of us fret about the hassles de-icing the airplane and the consequent departure delays this often causes?

As ice accumulates on a wing, the increase in drag and disruption of laminar airflow on the wing leads to unpredictable flight characteristics.  Ice can interrupt airflow around critical control surfaces, altering handling and reducing effectiveness.  As the aircraft must consequently be flown a higher angle of attack, there is a natural increase in stall speed and if the wing does stall, strong rolling motions are not uncommon.

Even though an aircraft may be certified to fly in known icing conditions, the best tool a pilot has against ice accumulation is avoidance of the condition altogether.  Aircraft sporting the most advanced de-icing systems have time and time again, flown consciously through icing conditions only to be easily outmatched by mother nature.  For this reason, aircraft de-icing equipment should be seen as a contingency, not a free pass to point the nose at inclement weather.  Ask the controller for pilot reports from other aircraft in the area if you suspect icing conditions exist.

Ideally, avoidance of icing conditions should begin before the aircraft ever leaves the ground.  Thorough checks of the weather along the flight-planned route should be made before leaving the hangar.  The "Clean-Aircraft Concept" advocates removing all ice from an aircraft before it becoming airborne.  Sometimes, something as seemingly minor as extending flap on an iced-up wing can alter the relative airflow beyond critical angle of attack leading to an unrecoverable spin - more than enough reason to spend those extra few minutes at the de-icing bay before takeoff.