AOPA Pilot Magazine - February 2018 - 96

P&E

ADS-B

Airlines, military
face the mandate
Solutions are becoming available, and they are pricey
BY MIKE COLLINS

SOUTHWEST AIRLINES currently operates about 700 Boeing 737s, and only the 14 newest

are ADS-B-equipped. While waiting for certification of a 1090ES transponder, the airline
has made wiring changes to expedite the installation of almost 1,400 new transponders-
two per jet-in the rest of the fleet.

96 | AOPA PILOT February 2018

how many aircraft require ADS-B capability. The FAA and Aircraft Electronics
Association have talked about equipage
requirements of 120,000 to 160,000 aircraft, but those forecasts are based on
aircraft with transponders. The actual
number on January 2, 2020, will be much
lower-maybe 70,000 or 80,000.
Why? Not all GA aircraft have to equip.
If you don't fly in Class A airspace; in and
above the 30-nautical-mile Mode C veils
surrounding Class B; in and above Class
C; or Class E airspace at and above 10,000
feet msl, excluding airspace at and below
2,500 feet agl-or at and above 3,000 feet
msl over the Gulf of Mexico, within 12
nm of the U.S. coastline-ADS-B is not
required.

MIKE COLLINS

IT'S NOW LESS THAN TWO YEARS until
January 2, 2020-when the FAA has
mandated installation of Automatic
Dependent Surveillance-Broadcast
(ADS-B) Out to fly in airspace where a
transponder is required today. ADS-B
uses satellites instead of ground-based
radar to determine aircraft location, and
is a key technology behind the FAA's Next
Generation Air Transportation System.
According to FAA data, as of December
1, 2017, 46,968 U.S.-registered aircraft had
equipped with ADS-B Out. Of that total,
34,400 are certificated fixed-wing general aviation aircraft, and another 1,542
are registered to U.S. air carriers.
It's hard to say how many more must
equip by 2020, because nobody knows

But the airlines can't choose not to
equip, or delay installations until 2020.
Their turbine aircraft can't fly efficiently
below 10,000 feet msl, and few can avoid
Class B and Class C airspace.
You may have heard about an exemption for the airlines. They do have a five-year
grace period, but it applies only to upgrading GPS position sources to fully comply
with ADS-B rules-airliners still have to
equip with ADS-B Out by January 2020.
Why aren't the airlines further along?
Some have made significant strides-
United Parcel Service's fleet is 99 percent
equipped, FedEx is at about 37 percent,
and United and JetBlue both are at about
35 percent.
Southwest Airlines currently operates 700 Boeing 737s. Only its 14 newest
jets, 737 MAXs, are ADS-B Out-equipped.
"The airlines can only buy things that are
for sale. Until three months ago, there was
nothing for us to buy," explained David
Bunin, a Southwest avionics engineer.
There were no certified ADS-B transponders or rule-compliant GPS receivers. Like
many GA aircraft, airliners are not WAAS
GPS-equipped-with multisensor flight
management computers that combine
inertial navigation, DME, GPS, and other
position sources, WAAS wasn't needed.
Changes to DO-260, the RTCA specification for Mode S Extended Squitter/
ADS-B transponders, partially caused the
delay in hardware availability. Europe's
ADS-B rules use the DO-260A standard, and the FAA mandated DO-260B
while DO-260C was being discussed.
"There were so many changes, the industry wasn't confident there wouldn't be
another change," Bunin said.
As a result, Air Transport hardware
providers such as Boeing, Collins, and
Honeywell didn't have solutions. "Not only
did they have to develop the transponder,
but they had to develop a WAAS GPS-
which they'd never done before-and get
it certified." That's the primary reason
behind the airlines' ADS-B position source
exemption, he added.
Now there's a 1090ES transponder
for Southwest's fleet, but the company is
waiting for a service bulletin authorizing
its installation. "What we've been doing
AOPA Pilot Magazine - February 2018

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