On the ground, de-icing is done by vehicles at the gate or by the aircraft
taxiing to an area set up for mulitple de-icing. Fluid is sprayed on the
aircraft which removes the ice and offers protection for a short while.
Crews have charts which evaluate the type of fluid used, the degree of icing
condition, etc,, and provide timing. The aircraft has to depart before that
time is up or de-ice again.

Most airline aircraft use pneumatic heat that is channeled to the leading
edges of wings, horizontal & vertical stabilizers, and other areas that are
vulnerable to icing. Other areas are electrically heated. While in icing
conditions engine and air foil anti-icing is turned on. Freezing rain can
only occur when a temperature inversion is present. That is, the air above
must be above freezing and rain coming from that altitude falls through
colder, freezing air. Normally this doesn't happen since temperatures are
normally colder at higher altitudes.

Icing can occur at any altitude as long as icing conditions exist but it is
rare at the cruising altitudes of commercial jets.

--
Darrell R. Schmidt
B-58 Hustler Web Site
http://members.cox.net/dschmidt1/
Cadet Class 55-I Web Site
http://pilotclass55india.org/
"Peter R." wrote in message
...
In watching a freezing rain/snow storm move from the midwest up to the
northeast US today, I again wonder how the airlines deal with freezing
rain. Are many flights canceled during a freezing rain storm or is it
business as usual?

Does a deicing on the ground and anti-icing equipment on the aircraft
provide the protection needed to fly into or out of freezing rain
conditions for the airline aircraft?

--
Peter