Avionics News January 2015 - 59

The mandate is for equipage only if the aircraft needs
tical to the STC, the installation is in accordance with the
to use the specified airspace. This means that not every
manufacturer's installation guidance, and AC 20-165A
aircraft will require ADS-B Out, especially if the aircraft
Chapter 3 and 4 are complied with. There are combinaowner doesn't want to use the designated airspace. For
tions of position sources and ADS-B units that, in theory,
example, an aircraft owner of a normally aspirated Aztec
ought to be able to be used but can't because there isn't
has a service ceiling of 21,000 MSL, but he doesn't
an STC for the pairing.
operate it above the mid-teens and wants a UAT system installed. He was told by an avionics shop that this
TECHNOLOGY SELECTION
wasn't permitted, and he was required to install a 1090
For aircraft that have an operational need to operate
ES transponder. This is incorrect. The correct advice
above 18,000 MSL, the ADS-B Out technology choice is
should have been that if the customer installs a UAT, he
simple - a Mode S transponder with 1090 ES is mandator she may not operate at 18,000 MSL or above, and they
ed. With two different technologies available to satisfy
should be advised of this fact.
the rule for the below 18,000 MSL
There also is confusion regarding
crowd, the one shops should recomoperation at towered airports within
mend for their customers is a more
AIRCRAFT OWNERS
Class D airspace. As long as the
nuanced call. For the piston crowd,
ARE LOOKING TO THEIR
airspace is not also part of a Class
most of the benefits of ADS-B are
C or B, or inside a 30 nautical mile
based on ADS-B In features and not
LOCAL AVIONICS REPAIR
veil, there isn't a mandate for ADS-B
on ADS-B Out. Both links, UAT and
SHOPS FOR GUIDANCE
in this airspace. There will be many
1090 ES, provide a traffic informaON WHAT SOLUTIONS
aircraft owners in the hinterlands
tion services-broadcast from the
TO INSTALL, AND HOW
because of low economic value and
ground-based transceiver, or better
never needing to go into the vicinity
known as the ADS-B ground staTO DO IT IN A RULEof a Class B or C airspace, and they
tions. However, the flight informaCOMPLIANT FASHION.
will choose not to equip. Even if on a
tion service-broadcast, more comUNFORTUNATELY, NOT ALL
rare occasion they need to visit an airmonly known as ADS-B weather, is
SHOPS ARE UP TO SPEED
port in the affected airspace, the rule
only available with UAT ADS-B In.
ON THE TECHNOLOGY AND
provides a means for contacting the
Since ADS-B In is not mandated,
ATC controlling facility with a onemany pilots have chosen to impleTHE REAL CHOICES.
hour notice and obtaining permission
ment this with portable receivers that
to use the airspace for the proposed
display on an iPad or iPhone. The
operation.
portable systems are becoming ubiquitous.
FAA POLICY
There isn't a requirement for the ADS-B Out and
The FAA has established policy guidelines for the
ADS-B In to use the same technology, so one can mix and
eligibility of equipment that may be installed to meet the
match. A common customer plan is to use a 1090 ES tranmandate. Essentially, a supplemental type certificate is
sponder with a portable receiver that receives UAT or both
required that includes both the position source and the
1090 ES and UAT. The dual frequency receivers are more
ADS-B avionics as a pair. Field approvals are permitted
popular and are rapidly becoming a de facto standard.
in cases where the STC does not cover a specific make
For panel-mount ADS-B In equipment, a key quesand model of aircraft as long as the equipment meets the
appropriate technical standard orders, the wiring is idenContinued on following page
avionics news

january

2015

Avionics News January 2015

Table of Contents for the Digital Edition of Avionics News January 2015