Pilot's Guide to Avionics 2015-16 Edition - 51
raise some eyebrows given the simplicity of the
packages. But with the inside-the-airframe nature
of installing these, the only simple part is making
While AoA systems available under this standard
are stand-alone, independent, and, as a design
trait, relatively simple to install, the labor involved
can be more involved, according to a number of
repair shop owners and technicians consulted.
The air sensors mount in an existing inspection
hole in the lower wing; the processor/brain goes
behind the panel; the indicator mounts either in
or on the panel, or on a cabin pillar. The options
available are considerable, but depend on the
Cutting and fitting a custom inspection cover with
the sensor mounted to it will take some time, as
will fishing through the wings the wiring and the two
flexible tubes for the pitot and static connections to
the processor brain.
From the wing root, the two tubes and the wiring
need to travel down through a fuselage pillar and
behind the panel to connect to the brain, which
requires being mounted square to the aircraft's
three axis, vertical, horizontal and longitudinal.
The display must be mounted - and at or
near eyeball level, to the side, is recommended;
mounting in the panel is another option, but
the indicator should be as close to eye level as
Thread the tubes and wires, connect, replace
covers and trim pieces, close inspection ports -
and tackle paperwork.
Expect somewhere north of a day's labor - one to
two days - according to the consensus from those
consulted shops and technicians already experienced
with installing systems built to ASTM F3011-13.
Log it, calibrate it, fly it
The paperwork requirement merely amounts to a
logbook entry. Calibration is still required; the pilot
can do that in most cases, but the shop could add
to its value by including calibration assistance in its
bid for installing the package. Otherwise, the AoA is
ready to work once logged and calibrated.
Then it's time for the pilot to learn how to use
this new tool.
To use wisely, send aircraft owners
to their CFI: Multiple options already
available with more to come
The NTSB recently played host to a one-day
workshop focusing on reducing LOC accidents,
which is expected to kick off other organizations'
similar efforts - and heightened promotion of the
new AoA options available as tools to avoid some
of the more-common LOC scenarios.
After more than a century of powered flight,
aviators across the world continue to crash after
making a fundamental mistake known to pilots
since the days of Otto Lilienthal, Octave Chanute
and, of course, the Wright brothers: flying too
slowly or stalling - by whatever means.
This new technology - and the different approval
approach used to help make it more affordable -
aims at aviation's earliest and oldest challenge after
liftoff: speed control, or put another way, pitch control.
Avoiding an unintended stall remains the old, ultimate
goal - particularly when in a turn or low to the ground
at pattern altitude or on an instrument approach.
Compared to needle-and-dial or digital strip
indicators, the AoA arguably offers pilots a moregraphic, more-intuitive indication.
While the indicators vary slightly in design,
their color coding and intuitive displays offer an
alternative pitch-management tool that presents the
aircraft's situation in a way that shows the proper
response at any attitude.
A down arrow indicates a need to push down or
lower the nose; an up arrow indicates a need to raise
the nose to achieve optimal lift for the power setting.
The round ball indicates the aircraft pitch is in
the sweet spot of optimal performance - and far
from too fast or too slow.
What AoA packages are currently available? As
examples, Alpha Systems, BendixKing and Garmin
qualify for installation under the ASTM F3011-13
standard, and some of these companies offer more
than one package with a choice of indicator types
for a broad range of mounting possibilities.
And in April 2015 at the AEA International
Convention & Trade Show, Aspen Avionics
introduced its integrated Evolution Angle of Attack
indicator. Unlike other AoAs, Aspen's patent-pending
solution seamlessly integrates AoA technology
directly into its Evolution primary flight and
multifunction displays. q
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