Freezing rain: What do the airline pilots do?

Jim Macklin wrote:

The FAA parts 121 and 135 do not allow take-off in certain
extreme icing conditions, but pilots have the authority to
NOT GO even when the regulation might allow.

The Canadian MOT doesn't allow takeoff with any ice. Some, however,
have forgotten that:

http://aviation-safety.net/database/...0117-0&lang=en

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

I see only two problems here, well maybe three:

Cruise altitude may not be 'too cold' for ice accumulation, ice
normally tends to fester from between -5 through -15 c.
You need to take off, and land flying through the muck. In some of the
worst cases, anti-ice and deice equipment cannot keep up with the ice
buildup wether it be wings, tail, control surfaces, windscreen,
propellers, if that is the case, bad scene. With a really bad ice
storm and freezing rain due to a widespread tempurature inversion,
most ground operations are stopped until conditions improve.

Have a great one!

Bush


3. getting ice on planes as they fly. Most commercial jets fly
really fast, which has two effects: first, it means that the planes
will fly through the freezing levels quickly (and up higher where it
is too cold for ice accumulation), so they don't pick up much ice.
Also, the wings and control surfaces get heated by the passing air,
and are warm enough that ice doesn't tend to stick to the plane. So
in many circumstances the jet can just fly through the freezing
conditions and not worry about it.


On Sun, 14 Jan 2007 10:05:01 -0500, "Peter R."
wrote:

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 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?

If the runway is useable, it's business as usual, except for delays incurred
for ground de-icing and inclimate weather.

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?

For jets, almost always. Airbus put wing anti-ice on the outer half of the
A-320 wings only because the FAA wouldn't sign-off on the design if they
didn't. The B-727 doesn't have anti-ice on the tail surfaces because ice
doesn't accumulate there to any appreciable degree. The MD-80 is approved to
take-off without performance penalties with an eight inch of frost on the
underside of the wing (clear ice on the topside of the -80 wing is a serious
problem but doesn't happen in flight).

D.