Icing Conditions

Question:  What special things do you have to do in order to fly into icing conditions?  How dangerous it is and how often do you fly in such conditions?  In what particular areas and at what altitudes do you expect icing?  Can you tell me about some of your personal experiences with icing?

Igor Giterman, New Haven, Connecticut

Answer:  Icing conditions normally exist with the combination of low visibilities and a temperature range from -10 degrees Celsius to +10 degrees Celsius.  Outside this temperature range or in greater visibility conditions ice doesn't form.  Usually we encounter icing conditions on the ground and up to maybe 10,000 feet MSL (Mean Sea Level) or so, although such conditions may exist at higher altitudes.  When you get too high, however, it gets colder than is conducive to ice formation.

Every instrument-rated pilot encounters icing conditions.  Well-equipped airplanes have both engine heat and wing heat, which melts the ice.  Some smaller planes may have "boots" on their wings which a pilot may use once ice has already formed.  The boots inflate and crack the ice off.

I only had one experience where the ice accumulation was faster than my airplane could handle, but we climbed out of the cloud layer and were out of the icing conditions quickly.  The ice then melted in a matter of just a few minutes.

Ice has caused crashes, but it's sometimes been because someone didn't do their job--they didn't clean their airplane of ice before takeoff, or didn't use their anti-icing systems correctly, etc. 

Sometimes ice has caused accidents indirectly, such as the Air Florida plane that crashed near Washington National (now Reagan National).  The accident report found the pilots did not use their anti-ice systems, resulting in numerous problems including erroneous engine indications.

Pilots are forbidden by Federal Aviation Regulations (FARS) and usually airline policies to knowingly fly into heavy icing conditions.

Before flight, if ice is adhering to any of a plane's surfaces, de-icing fluid is applied.  Although  de-icing a plane is at the discretion of the captain, many times he or she will arrive at the plane to find it already de-iced.

De-icing a plane before takeoff is a measure taken after ice has already accumulated, while engine and wing anti-icing are meant primarily to prevent ice formation.

The last plane I flew for the airlines was the beautiful B-777, so sophisticated that it turned on its own anti-icing systems on when needed.  The pilot could always override the automatic feature to turn the system on as well, of course. 

Gotta love it (and I did).