Avionics News February 2016 - 27
Today, the aircraft most likely to lack an approved
solution sit at the upper ranges of the spectrum - the
business-turbine fleet and some older turboprop aircraft.
Nonetheless, solutions for those segments continue to
grow in number.
By 2020, according to some
avionics insiders, it will be a
rare aircraft for which exists no
approved ADS-B Out solution. No
doubt, the cost of some solutions
may raise questions about the
wisdom of spending money to
upgrade some rarer and older
airframes. But for most of the
fleet, the ability to access positivecontrol airspace above and below
Flight Level 180 will remain a
necessity - even though many
will rarely, if ever, file to fly under
instrument flight rules or need
to transit a Class Bravo airspace
As pilots use their Mode C and
Mode S transponders to secure air-traffic service handling,
they'll need ADS-B Out.
The gains in safety, capacity, and efficiency as a result
of moving to a satellite-based system, the agency stresses,
will help the U.S. meet the growth in air traffic in coming
WAAS GPS data, the most common source for ADS-B position
data, is accurate to about 1/100 of
a nautical mile - 60 feet laterally,
even less vertically.
The FAA established two ways
to comply and transmit that position data, one theoretically less
expensive than the other. The
international standard of a Mode S
transponder broadcasting on 1090
MHz with extended squitter, or on
978 MHz using a universal access
transceiver equipped to also receive
With ADS-B In, pilots gain
access to the FAA's Flight Information Service-Broadcast and
the Traffic Information ServiceBroadcast. For maximum situational awareness, many also
will opt for ADS-B In - and receiving both 978 MHz and
1090 MHz, allowing them to directly see aircraft on both
To fly above Flight Level 180, or 18,000 feet mean sea
level, the aircraft must be using 1090 ES; below, it's the
owner's option. Aircraft flying internationally may want to
use 1090 ES - the standard everywhere outside the U.S.
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Why are we making this trip?
The question repeatedly arises when talking to many
pilots - particularly those not immersed in aviation.
According to the FAA, ADS-B establishes the foundation
necessary for many other NextGen advances. Additionally,
ADS-B provides a flexible and expandable system that can
change with the evolving aviation system.
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