Flying through known or forecast icing

Gary Drescher wrote:

So according to the AIM, forecast icing is not tantamount to known icing.
Rather, only a PIREP of icing (or a pilot's own observation in flight)
constitutes known icing.

Here's the punch line from one of Yodice's columns in AOPA Pilot. Emphasis added.

"The NTSB precedents are clear. Relevant pireps *and forecasts* constitute
'known icing conditions' into which a flight is prohibited unless the aircraft
is specifically certificated by the FAA for flight into known icing conditions."

AOPA members can view the entire article here
http://www.aopa.org/members/files/pi...05/pc0508.html

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

"George Patterson" wrote in message
news:GJhof.1362$Jr1.200@trnddc01...
Gary Drescher wrote:

So according to the AIM, forecast icing is not tantamount to known icing.
Rather, only a PIREP of icing (or a pilot's own observation in flight)
constitutes known icing.

Here's the punch line from one of Yodice's columns in AOPA Pilot. Emphasis
added.

"The NTSB precedents are clear. Relevant pireps *and forecasts* constitute
'known icing conditions' into which a flight is prohibited unless the
aircraft is specifically certificated by the FAA for flight into known
icing conditions."

Right, but the NTSB precedents cited are not recent (some are more than
thirty years old), whereas the FAA's current definition of "known icing
conditions"--which I quoted from the latest AIM--explicitly contradicts
those precedents.

--Gary

Gary, the most recent case was in 2005. That's what George was linking to.

Bob Gardner

"Gary Drescher" wrote in message
...
"George Patterson" wrote in message
news:GJhof.1362$Jr1.200@trnddc01...
Gary Drescher wrote:

So according to the AIM, forecast icing is not tantamount to known
icing. Rather, only a PIREP of icing (or a pilot's own observation in
flight) constitutes known icing.

Here's the punch line from one of Yodice's columns in AOPA Pilot.
Emphasis added.

"The NTSB precedents are clear. Relevant pireps *and forecasts*
constitute 'known icing conditions' into which a flight is prohibited
unless the aircraft is specifically certificated by the FAA for flight
into known icing conditions."

Right, but the NTSB precedents cited are not recent (some are more than
thirty years old), whereas the FAA's current definition of "known icing
conditions"--which I quoted from the latest AIM--explicitly contradicts
those precedents.

--Gary

"Bob Gardner" wrote in message
...
"Gary Drescher" wrote in message
...
"George Patterson" wrote in message
news:GJhof.1362$Jr1.200@trnddc01...
"The NTSB precedents are clear. Relevant pireps *and forecasts*
constitute 'known icing conditions' into which a flight is prohibited
unless the aircraft is specifically certificated by the FAA for flight
into known icing conditions."

Right, but the NTSB precedents cited are not recent (some are more than
thirty years old), whereas the FAA's current definition of "known icing
conditions"--which I quoted from the latest AIM--explicitly contradicts
those precedents.

Gary, the most recent case was in 2005. That's what George was linking to.

No, the AOPA article he linked to says explicitly that the issue of known
vs. forecast icing conditions was *not* addressed in the most recent case
that the article discusses. The article goes on to say, "The board addressed
this issue most recently more than a dozen years ago, and in 1974 and 1976
before that. All are old cases."

Also, the article begins by saying that "the FAA offers very little guidance
to pilots operating 'non-commerically'" regarding what is meant by "known
icing conditions". In fact, though, the current AIM defines the term clearly
(and clearly distinguishes it from "forecast icing conditions"); the article
makes no mention of the AIM's definition.

Therefore, either the AIM definition first appeared after the article was
written, or else the article's author was unaware of the FAA's
already-published definition. Either way, the article does not provide sound
legal guidance in light of the FAA's current definition.

(George's link again:
http://www.aopa.org/members/files/pi...05/pc0508.html.)

--Gary

Gary
If you wait just a little, the legal definition will change again and
the hapless pilot will still be shafted and left bankrupt trying to
defend against the FAA steamroller legal section.
While I am pleased to see some really good input from the practical
standpoints, I'd hate to see it change into a legal discussion and
forget the original intent was ice and how to cope with it.
I've written at least a half dozen published articles on ice in general
aviation and so far they have withstood the test of time. As anyone
knows though, longevity lends credence to nearly any stated position if
its restated enough!?
Best Regards and Merry Christmas/Happy New Year
Ol Shy & Bashful

wrote in message
oups.com...
If you wait just a little, the legal definition will change again and
the hapless pilot will still be shafted

That seems unlikely for the foreseeable future. But if the definition does
change, someone here is likely to call attention to it.

While I am pleased to see some really good input from the practical
standpoints, I'd hate to see it change into a legal discussion and
forget the original intent was ice and how to cope with it.

Yup, legality and safety are not synonymous. Still, I think it would be safe
to fly IFR through a thin cloud layer (with plenty of room above and below)
even if there's a forecast for occasional moderate icing in clouds. And
according to the AIM's current definition of "known icing conditions", that
would be legal (for Part 91), as long as there are no PIREPs that confirm
the forecast.

Best Regards and Merry Christmas/Happy New Year

A cheerful solstice to you too!

--Gary

"Gary Drescher" wrote

Yup, legality and safety are not synonymous. Still, I think it would be
safe
to fly IFR through a thin cloud layer (with plenty of room above and
below)
even if there's a forecast for occasional moderate icing in clouds. And
according to the AIM's current definition of "known icing conditions",
that
would be legal (for Part 91), as long as there are no PIREPs that confirm
the forecast.

Section 91.527: Operating in icing conditions.

(b) Except for an airplane that has ice protection provisions that meet the
requirements in section 34 of Special Federal Aviation Regulation No. 23, or
those for transport category airplane type certification, no pilot may fly—

(1) Under IFR into known or forecast moderate icing conditions; or

(2) Under VFR into known light or moderate icing conditions unless the
aircraft has functioning de-icing or anti-icing equipment protecting each
propeller, windshield, wing, stabilizing or control surface, and each
airspeed, altimeter, rate of climb, or flight attitude instrument system.

(c) Except for an airplane that has ice protection provisions that meet the
requirements in section 34 of Special Federal Aviation Regulation No. 23, or
those for transport category airplane type certification, no pilot may fly
an airplane into known or forecast severe icing conditions.

(d) If current weather reports and briefing information relied upon by the
pilot in command indicate that the forecast icing conditions that would
otherwise prohibit the flight will not be encountered during the flight
because of changed weather conditions since the forecast, the restrictions
in paragraphs (b) and (c) of this section based on forecast conditions do
not apply.

It appears that for purposes of an IFR flight the rules do not rely on any
definition of "known" versus "forecast" - they're both covered right in the
reg. Paragraph (d) appears to allow a pirep of no icing to supercede the
forcast.

The situation seems to be, for part 91 ops, that if it is forecast,
that is if there is an AIRMET for icing (AIRMET ZULU), then it's not
legal to fly in it without approved deice equipment. But.....no one
enforces it (for part 91), and it is known that part 91 aircraft do fly
in it (by ATC), and so long as you don't declare an emergency or crash,
I don't think there has ever been a citation for it.

Having said that, I don't think its a very good idea to launch with
airmet ZULU along your route, but there may be some exceptions (like
when you have VFR beneath you above the MEA), or you have a pilot
report from a pilot who was just in it and not only didn't he pick up
ice, but he doesn't think there IS icing in those clouds. Also,
decending through a thin layer of rime (like 1000' thick) and it is
known that you wont get ENOUGH ice to affect your aircraft.

Statistically, its not a big problem. There aren't that many crashes
due to icing (there are some), but that doesn't mean its safe, just
that pilots are handling the hazard (usually by not flying in it).

But the fact that part 91 aircraft do it, and don't crash, doesn't make
it legal. Just makes it that they are getting away with it.

I think they should make icing a "percent probability" and when the
probability is greater than some figure (say 30%) then it's a no go.
This would allow them to given the 30% icing figure indicating ice, but
keep it at 30% indicating there is VFR under it or that the layer is so
thin, it is not likely to cause problems.

What you really want to aviod is being trapped in it with no VFR under
you, no ablity to outclimb it, and no way to turn around (although its
hard to imagine NOT being able to turn around, fuel, I guess).

Anyway, talk to pilots who have picked up ice and you will get the idea
that it is not, in general , a good idea. In fact, avoid it. That is
what I do.

Bob Gardner wrote:

Gary, the most recent case was in 2005. That's what George was linking to.

No, that's the date of the article. The most recent ruling on the forecast icing
issue was about 12 years ago. There were earlier ones as well. If, however, the
AIM is in conflict with case law (and it is), the AIM is wrong.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

"George Patterson" wrote in message
news:_Qpof.17301$Jz6.14963@trnddc06...
Bob Gardner wrote:

Gary, the most recent case was in 2005. That's what George was linking
to.

No, that's the date of the article. The most recent ruling on the forecast
icing issue was about 12 years ago. There were earlier ones as well. If,
however, the AIM is in conflict with case law (and it is), the AIM is
wrong.

The AIM presents the FAA's current official definition of "known icing
conditions". So any case law decided on the basis of prior explicit or
implicit definitions is no longer applicable.

--Gary