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Etihad's International ADS-B Upgrade Strategy

Etihad Airways provides an international perspective on the challenges of fielding a fleet of internationally ADS-B-compliant commercial air transport airplanes.

At the 2018 AMC/AEEC annual conference, an ADS-B symposium allowed Avionics to gain a first-person perspective on ADS-B mandate compliance upgrades from an Etihad Airways engineer that is on the ground dealing with the wiring, transponder, TCAS computers, GPS sources and the other avionics upgrades other airlines are also dealing with. The Middle Eastern airline is registered to operate under the General Civil Aviation Authority, the civil aviation regulatory authority for the United Arab Emirates (UAE). But it also flies in European and North American airspace, both of which have their own respective ADS-B equipage mandates aside from GCAA’s. Here, we breakdown Etihad’s path to ADS-B compliance, including the tough decisions it will have to make between 2018 and 2025.

Etihad’s International ADS-B Strategy

Borja Roiz is a senior avionics and electrical systems engineer for Etihad Airways, with first-person avionics wiring, computer, transponder touching on the ground perspective on international ADS-B compliance. In September 2017, the UAE’s GCAA provided a reminder on the ADS-B and other avionics mandate compliance Etihad is facing at home before even addressing the FAA’s ADS-B Out mandate. GCAA published an information bulletin noting that its regulatory ATM requirements include the need for operators to equip with GNSS by December 2017 and ADS-B Out by Jan. 1, 2020.

“Even though we’re in April 2018, we still have not decided which of the transponders that we’re going to install in our fleet,” said Roiz.

But Etihad’s engineering team has already plotted out the number of man-hours that would be required to perform the installations.

Currently, the engineering and maintenance team that Roiz is a part of is focused on installing its wiring provision. The team developed a wiring installation upgrade internally, and has begun working through that for its Boeing fleet. Upgrading its Airbus A320/330 fleet has proven more challenging, though, as Etihad purchased service bulletins from Airbus that will allow the airline to perform the mandatory DO-260B wiring provisioning for the future installation and activation of the DO-260B transponder. However, as reported by Etihad during the open discussion session of the annual AMC meeting, Airbus is providing the wiring kits at an average rate of one per month, which has not aligned well with Etihad’s plan to install them during aircraft C-checks. Further complicating the matter is Etihad’s A320 fleet is split into four different configurations that are applicable under the service bulletin, requiring four different kits for the desired modification.

At this point, between the U.S.-operated Airbus and Boeing aircraft, Etihad will need to install 168 new ADS-B DO-260B transponders. Roiz said that it has also mapped out the number of hours required for the ADS-B per aircraft, noting that it breaks out to 14 hours for each A320, 18 hours for each A330 and between three and 15 hours for every Boeing 777 in its fleet.

An important decision that Etihad and other carriers also have to make is the decision to select an OEM’s service bulletin or to establish their own STC path.

“STC is a little more complex,” said Stephane Chartier, a former applications engineer turned senior air transport sales manager for L3. The STC process, Chartier said, is also more complex within the U.S. where the FAA requires a flight test for any new pairing of TCAS transponder and GPS source that it has not previously provided certification on. If a flight test is required, it “can take seven to nine months to get a full certification,” Chartier said during his presentation at the ADS-B Symposium.

The SBAS MMR Challenge

Where the challenge comes in for Etihad is deciding how to provide an upgrade path for the FAA’s Navigation Accuracy Category for Position (NACp) and its Navigation Integrity Category (NIC) in 91.227.

“In UAE it’s standard. Just a DO-260B transponder; that’s no problem. In European airspace, it’s the same situation. You just have to buy one and put it on your airplane,” said Roiz. “The challenge comes in the FAA airspace. They’re asking for not only a DO-260B transponder, they’re asking for an SBAS MMR, which are not even certified today.”

n U.S. airspace, operators must equip with a DO-260B transponder and an SBAS MMR.Photo courtesy of Etihad Airways

Etihad operates a fleet of 178 total Airbus and Boeing aircraft, including Airbus A320s, A330s, A350s and A380s, as well as Boeing 787-9s and 777s. It also has a total of 51 787s on order and expects to add an additional 10 787s this year.

At this point, between the U.S.-operated Airbus and Boeing aircraft, it will need to install 168 new ADS-B DO-260B transponders.

“Finding the time — that’s the biggest challenge,” said Roiz.

All of the above mentioned aircraft go through C checks every two years, Roiz said.

The primary challenge that Etihad and many other U.S. and non-U.S.-based air carriers are facing in trying to comply with the 2020 ADS-B mandate is the navigation requirement in the U.S. leading to the need to equip with an SBAS MMR. Based on the available in-service in-production commercial air transport category aircraft today, the Airbus A350 and Boeing 737 MAX are the two in-production aircraft that Airbus and Boeing provide featuring an SBAS MMR as standard equipment.

“Ideally we will need another C check for this transponder installation and activation, and right now we’re too close to the mandate and don’t have time to do it,” said Roiz, referring to Etihad’s transponder and MMR upgrade needs. “In our case, we will run out of time. We will have to ground the airplanes to do the modification.”

The two available options to meet the SBAS MMR requirement include the IMMR from Honeywell Aerospace and the GLU 2100 MMR from Rockwell Collins. Certification of these two systems isn’t expected until 2019.

But by Aug. 1, Etihad will have to submit the SBAS MMR upgrade path that it will need to qualify for an exemption to the navigation accuracy requirement that the FAA has provided to operators of all categories of aircraft.

The European Global Navigation Satellite Systems Agency (GSA) defines SBAS as a GNSS measurement provided by navigation reference systems deployed across an entire continent. The systems provide corrections on the positioning information provided by sources of GPS information, such as the aircraft GPS receivers used to provide ADS-B systems with the position of the aircraft in reference to the curvature of the earth. “All measured GNSS errors are transferred to a central computing center where differential corrections and integrity messages are calculated. These calculations are then broadcast over the covered area using geostationary satellites that serve as an augmentation, or overlay, to the original GNSS message,” according to the GSA. What SBAS effectively does is to add additional satellites to the constellation that are stationary above a certain location.

Etihad Airways operates 178 Airbus and Boeing aircraft.Photo courtesy of Etihad

By eventually adding the SBAS capability, Etihad and all other airlines will be able to take advantage of the ground station infrastructure that has already been implemented in countries such as the U.S. with its WAAS system. Europe has the European Geostationary Navigation Overlay Service (EGNOS), and India has its GPS and GEO Augmented Navigation (GAGAN) system. China is currently developing its own Satellite Navigation Augmentation System (SNAS). South Korea and Russia are also currently developing their own nationwide SBAS systems.

Still, Etihad is left with the need to provide the FAA with a detailed upgrade plan on how it will eventually exist with a technology that is not widely available.

“We have to submit a very detailed upgrade plan to contain each and every aircraft in our fleet and should detail what MMR SBAS compliant you will install on your aircraft,” said Roiz.

The Etihad engineer admits that completing all of the necessary transponder upgrades by Jan. 1, 2020, will be a challenge and could lead to grounding some of its aircraft. But he expects Etihad and its commercial airline counterparts to eventually come up with the best last-minute solution.

“As airlines, we’re very good working under pressure and doing everything last minute. This is coming, and this is what we need to do. Even if we end up doing everything at the last minute, we end up doing it. We will succeed,” said Roiz. AVS