Safety

Photo courtesy of Avidyne
Synthetic vision displayed on a cockpit display.
We now have two technologies that allow us to
literally see through the dark and the clouds. While
there is some overlap in this technology, this article
will focus on Enhanced Vision (EV) and Synthetic
Vision (SV), rather than night vision. For more information
on night vision, please see the articles listed
in the Learn More section. EV and SV use very different
approaches and technologies to give you a bright
and clear picture of the outside world, no matter how
dark or cloudy the sky may be. Naturally, each of
these approaches has its advantages and drawbacks.
Synthetic Vision
SV is by far the more accessible in terms of cost
and equipment. It relies on marrying technologies
already included in many avionics
suites and even some hand-held
EV allows a pilot to see through
systems. SV uses a detailed and high
darkness, smoke, haze, smog,
quality database of terrain features
dust, light fog, and even rain.
and obstacle data to create a virtual
‘world.’ The SV system uses an accurate aircraft position
provided by an on-board GPS to display this virtual
world around your aircraft. The advantage of this
system is that regardless of the weather or light conditions,
you will have a “clear view” out of the front of
the aircraft. You could literally paper the windshield
of the aircraft (not a suggestion, mind you!) and still
see outside. It’s important to remember that SV is not
a navigational system. SV designed to improve situational
and terrain awareness and is not intended, or
authorized, to be used as a navigational system.
There are two potential faults though — location
data and database information. While GPS is usually
very reliable, its weak signal is vulnerable to interference.
Although, the FCC has done a great job of
shielding GPS frequencies, the possibility exists that
someone transmitting on or near those frequencies
could potentially jam the GPS. And of course there’s
the potential for active interference or spoofing,
but that’s usually limited to military action. These
GPS issues are not a fault with SV and apply to any
system that uses GPS.
The other potential issue is the quality and
currency of the database used to create the virtual
world your aircraft is relying on for safe navigation.
While terrain is pretty much static, obstacles are
constantly changing. This is probably the biggest
issue with SV, because what you’re seeing may not
be a 100 percent accurate depiction of the actual
world outside. In other words, your SV system is
only as good as the its foundational database. So it is
worth investigating how adept a system is at creating
and updating that database.
But perhaps the best advantage SV has is its relatively
low cost. You can add it to many popular flight
instrument systems or even utilize systems built into
accessories like a portable GPS unit, or an app on
your tablet. There are many variables, so it’s worth
investigating which one best suits your needs.
Enhanced Vision
EV may seem like a close cousin of Synthetic
Vision, but it’s actually a very different technology. EV
uses sensors on the aircraft to “see through” weather
or darkness. While this sensor comes in a variety of
forms, by far the most common is infrared (IR), which
senses temperature differences and produces a high
quality real-time image of the outside scene. EV
allows a pilot to see through darkness, smoke, haze,
smog, dust, light fog, and even rain. In heavier conditions,
EV may lose some of its ability relative to SV,
but what it shows you is what’s actually out there, not
what the database says should be out there.
There are a wide variety of EV systems on the
market and prices vary greatly, for good reason. The
older and more advanced systems use a super cooled
IR sensor to allow the sensor to more easily detect
the temperature differences. However, these systems
26 FAA Safety Briefing May/June 2016