Recently, I wrote the EAA and asked if there was
any specific guidance they knew of regarding icing equipment for flight into
"known ice" for experimental airplanes. The requirements are all in Part 23--but
that doesn't apply to experimental aircraft.
Everyone knows that we should stay out of
ice, but what about that case when you want to go through layer climbing to
cooler air on top, or descending through layer into warmer air. Known
ice?? Are we in violation? What ARE the rules?
Having researched the subject myself, I find
myself in complete agreement with Joe Norris in his first paragraph.
After that----------------. Anyone else have any ideas?
Charlie K.
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"Hello
Charlie,
There is no specific
guidance pertaining to amateur-built aircraft certification for flight into
known icing. This is no doubt due to the fact that 14 CFR Part 91 does not
specifically prohibit fight into known icing. In fact, other than
regulations that apply to large and turbojet-powered aircraft (specifically
mentioned in 91.527) icing isn't mentioned in Part 91 at all. There are
regulations applicable to flight into known icing found in Parts 121
and 135, but amateur-built aircraft cannot be operated under these
regulations, so these won't apply to your Lancair.
There is
specific guidance on certification of Part 23 (type-certificated) aircraft for
light into known icing. Guidance on this procedure can be found in FAA
advisory circular AC 23.1419-2B, as well as other references. While this
guidance does not directly apply to amateur-built aircraft, it may be used as
general guidance should you decide to equip your aircraft with icing
protection. Some items to be considered, as called out in AC 23.1419-2B,
include the following:
(1) Leading edges of wings,
winglets, and wing struts; horizontal and vertical stabilizers; and other lifting
surfaces;
(2) Leading edges of control surface
balance areas if not shielded;
(3) Accessory cooling air intakes
that face the airstream and/or could otherwise
become restricted due to ice accretion;
(4) Antennas and masts;
(5) Fuel tank vents;
(6) External tanks, including fuel tip
tanks;
(7) Propellers;
(8) External hinges, tracks, door
handles, and entry steps;
(9) Instrument transducers
including pitot tube (and mast), static ports, angle-of-attack sensors, and stall warning
transducers;
(10) Forward fuselage nose cone and
radome;
(11) Windshields;
(12) Landing gear;
(13) Retractable forward landing
lights;
(14) Ram air turbines;
(15) Ice detection lights if required;
and
(16) Any other external
protuberance.
Other
guidance on the certification of Part 23 aircraft for flight into known icing
can be found at the following web site:
Scroll
down the page until you see 23.1419 in the left-hand column. This is the
regulation on ice protection. Applicable references are listed in that
area of the web page.
Another
advisory circular which would be of use to you is AC 20-73A, which talks about
testing procedures used to verify the safety of ice protection systems.
Such things as testing methods, ice shedding, holding in icing conditions, and
other safety-related issues are discussed in this AC.
On
another subject, installing ice protection equipment on your aircraft will
constitute a major change, which must be approved in accordance with the
procedures called out in your aircraft's operating limitations. make sure
you check your operating limitations to verify what procedure applies to your
aircraft, and proceed as directed. Depending on when your aircraft was
originally licensed, this may or may not involve contacting your area FAA Flight
Standards District Office (SOD) in order to get written authorization for the
change. And even if SOD contact is not required, you will be required to
test the major change in order to verify that it does not present an unsafe
operating condition. In the case of ice protection equipment, the FAA may
very well take the position that testing in accordance with the procedures
outlined in the above-mentioned advisory circulars is the appropriate way to
test such a modification.
Another
consideration is insurance coverage. Before spending the time and money to
install the ice protection equipment, I would suggest that you call your
insurance underwriter and make sure they will cover operations of your aircraft
in known icing conditions.
I hope
this has given you some feel for what must be considered when contemplating the
installation of ice protection equipment on your
aircraft."
Joe
Norris
EAA Aviation Information Services
EAA Aviation Center, Oshkosh,
WI
888-322-4636, extension 6806
jnorris@eaa.org