AOPA Pilot Magazine - January 2014 - 85

P&E

WX WATCH

FIKI insights

Bose A20
®

What you may not know about known-ice certification

®

Aviation Headset

BY THOMAS A. HORNE

The best we've ever made.

THERE HE GOES- out the door, onto the
ramp, and into his airplane. Yes, he's had
a weather briefing, and yes, it did mention icing-in both airmets and pireps.
He even went online to check the current and forecast icing potentials (CIP
and FIP, respectively) on the icing tab of
the Aviation Digital Data Service (ADDS)
website (www.aviationweather.gov), in
the Supplementary Icing Information
field. There, the pilot saw that a better
than 50-percent chance of icing conditions could exist along his proposed
altitude and route of flight. Still, he picks
up a clearance and launches. He's even a
bit smug. After all, his airplane is certified for flight into known icing-FIKI, for
short.
Does this mean the airplane is safe to
fly in icing conditions? Yes and no. Yes,
if the pilot considers the ice-protection
equipment as escape tools to be used as a
means of exiting icing conditions as soon
as they are encountered, or if only small or

"not-so-bad" amounts of ice accrete. No, if
the pilot carries on as though the airplane
were invincible in the face of any and all
forms of icing.
It's been said before, but it bears
repeating: FIKI-certified or not, airplanes cannot drone on indefinitely with
heavier ice buildups. Eventually drag will
increase, lift will decrease, and handling
characteristics will degrade. Making all
this more complex is the fact that all these
negatives vary from airplane to airplane.
For example, wings with larger leadingedge radiuses (think Piper Aztec) are less

ICING ENVELOPES, as published in FAR Part
25, Appendix C, show conditions for two
different combinations of icing variables.
Note how much lower the liquid water
contents are in continuous maximum
conditions (below) compared to the very
soggy clouds of intermittent maximum
conditions (right). Which conditions might
you have encountered last?

* Acclaimed noise reduction
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* Auxiliary audio input
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Focus on
what matters.

Flying.

CONTINUOUS MAXIMUM (STRATIFORM CLOUDS) ATMOSPHERIC ICING CONDITIONS

LIQUID WATER CONTENT - GRAMS PER CU. METER

(LIQUID WATER CONTENT VS MEAN EFFECTIVE DROP DIAMETER)
0.9

1. Pressure altitude range, S.L.-22,000 ft.
2. Maximum vertical extent, 6,500 ft.
3. Horizontal extent, standard distance of
17.4 Nautical Miles.

0.8
0.7

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0.6

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2°
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14°
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AIR
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TEM ERATU
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4°F
ATUR
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0.5
0.4
0.3
0.2
0.1
0.0

15

20

25

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TAKE THEM FOR A 30-DAY,
RISK-FREE TEST FLIGHT.

To order 1.800.486.2043
Learn more at Bose.com/A20_4

35

Risk-free refers to 30-day trial only, requires product
purchase and does not include return shipping.
Delivery is subject to product availability.

40

MEAN EFFECTIVE DROP DIAMETER - MICRONS

www.aopa.org/pilot AOPA PILOT | 85
BOS78550A_102608v.indd 1

8/16/13 12:25 PM
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AOPA Pilot Magazine - January 2014

Table of Contents for the Digital Edition of AOPA Pilot Magazine - January 2014
