There was an earlier thread on whether it was legal to fly an airplane under
part 91 into known icing if there was no specific prohibition against it in
the airplane's operating handbook. I asked the Seattle FSDO what their take
was on the issue. This is their reply:

Dear Mr. Campbell:

Thanks for your e-mail asking where the prohibition against flight into
known icing conditions resides in the Federal Aviation Regulations (FARs).

I am a Principal Operations Inspector with the Seattle FSDO and am assigned
to answer your question.

Actually, until a couple of weeks ago, I, like yourself, believed that it
resided in some dark part of Part 91 that I was not familiar with.

Unfortunately, at that time one of our brethren pilots caused me find out
the exact answer to this question. The rule is FAR 91.9 - "Civil Aircraft
Flight Manual, Marking, and Placard Requirements," paragraph (a). It says,
in short, "... no person may operate a civil aircraft without complying with
the operating limitations specified in ...." a Flight Manual specific to the
aircraft, by markings or placards, or ".... otherwise prescribed by the
certificating authority." Most light aircraft (i.e., Cessna 172s) have
either a specific placard and/or a mention in the operating handbook that
flight into known icing is forbidden. The unhappy pilot in question is
facing a violation for operating contrary to the operating limitations of
the aircraft by flying into icing conditions he knew existed (by virtue of a
briefing).

This goes back to how the aircraft was originally "type" certificated. In
the case of light single engine aircraft, such certification is done under
FAR Part 23. I think the tendency most of us have is to think that an
aircraft that has such a prohibition has been tested and failed. Of course,
what the prohibition in the type most likely means is that the aircraft has
not been tested in a known hazard. In the case of icing, it was probably
wisely assumed that such an operation with such an aircraft would likely
have a negative result.

If you consider the opposite situation, aircraft approved for flight into
known icing conditions have had specific testing, specific additional
equipment, and specific limitations added to the basic aircraft.

We are hoping that you will help us and the rest of the flying community
spread the word on how this "icing" limitation works in the FARs because our
experience tells us that there are folks flying who firmly believe that if
it's not written down, it must be okay to do it.

Thanks again. Please call me at (425) 227-2240 if you have other questions.



Dennis Franks, Seattle FSDO



----- Forwarded by Dennis Franks/ANM/FAA on 12/09/2003 05:26 PM -----


Sarah

Perotka-Moye To: Dennis Franks/ANM/FAA@FAA

cc:

12/06/2003 06:13 Subject: Flight into known icing conditions

PM

Dennis--

I overlooked this message, so it is coming to you late. Please respond to
Mr. Campbell and cc me on your response. I'll print out the question and
response for the files, so you don't need to.

Thanks,

Sarah

----- Forwarded by Sarah Perotka-Moye/ANM/FAA on 12/06/2003 06:10 PM -----


"Christopher J Campbell" To: Sarah Perotka-Moye/ANM/FAA@FAA

Subject: Flight into known icing conditions


12/01/2003 08:59

AM

Sarah,

We were talking about flight into known icing conditions the other day, and
someone asked where it is actually prohibited by the FARs. FAR 91.527
applies only to large and turbine powered aircraft, and Part 135 has its own
language prohibiting flight into known icing conditions, but there appears
to be no specific prohibition that applies to general aviation aircraft
under part 91. The only thing that I can find on the subject is the
prohibition against flight into icing conditions in the Limitations section
of the operating handbook in most modern light aircraft.

It would be helpful if I had any additional references that I could direct
my students to. Or am I wrong on this matter?

Christopher Campbell, CFII


--
Christopher J. Campbell
World Famous Flight Instructor
Port Orchard, WA


If you go around beating the Bush, don't complain if you rile the animals.