ATM Modernization, Business & GA, Commercial, Embedded Avionics

Bruce DeCleene: The Four Areas of Performance-Based Airspace

By Juliet Van Wagenen | October 14, 2015
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[Avionics Today 10-14-2015] Bruce DeCleene, manager of the flight technologies and procedures division at the FAA, kicked off the second day of the Avionics for NextGen conference in Herndon, Va., Wednesday, speaking on how performance-based airspace can set standards, while leaving room for evolving avionics technology.

The successful implementation of PBN procedures have helped increase safety and efficiency in areas of high capacity. Photo: Tetra Tech

“At its core, [performance-based airspace] is a strategy for implementation that involves agility and flexibility from an operational and regulatory domain. When we say something is being implemented as a performance-based — whether it’s an operation or a standard or airspace regulation — what we’re trying to do is describe the characteristics that we want to see without describing the solution. What that does is allows agility and evolution for technology over time,” said DeCleene.

According to DeCleene, the FAA is applying performance-based standards to four separate domains in airspace: communications, navigation, surveillance and intelligence. While the FAA official didn’t elaborate much on performance-based information — although he noted there was much going on with Airborne Access to System Wide Information Management (SWIM) — or AATS, he did speak to the successes as well as the progress being made in performance-based communications, navigation and surveillance.

Performance-Based Navigation (PBN) is one of the first domains in which performance-based technologies and procedures were implemented across the National Airspace System (NAS) in order to upgrade airspace from the VHF Omnidirectional Range (VOR) navigation system and, fixed-ground infrastructure routes to a more dynamic environment for aircraft. PBN equipment allows an aircraft to fly precisely on a desired flight path within coverage of ground- or space-based navaids or with onboard aircraft systems, all of which leads to increased traffic capacity as well as reduced delays, fuel bills, emissions and noise.

PBN procedures are currently being implemented in a wide swath of operations, such as Metroplex upgrades as well as specific route procedures, including Optimized Profile Descents (OPDs), Area Navigation (RNAV) and Required Navigation Performance (RNP). It is also a mainstay in the transformation of the NAS from ground-based to satellite-based navigation. And, according to DeCleene, PBN implementation has, thus far, been highly successful.

“We really have succeeded at deploying this PBN infrastructure,” said DeCleene. “Of all public airports in the United States that have any kind of instrument approach, 98 percent of them have a PBN approach.”

DeCleene goes on to note that, of these, 25 percent of PBN airports are equipped with only PBN approaches. This represents airports where operators were previously unable to fly Instrument Landing System (ILS) procedures, but, because of the low cost of implementing a PBN infrastructure at individual locations, the FAA was able to implement new instrument access through PBN.

The FAA is looking to double up on PBN success and, going forward, the organization has kicked off an effort to develop a broad umbrella performance-based navigation strategy over the next 15 years.

DeCleene hinted the new roadmap would focus on implementing the PBN operation over just rolling out the infrastructure. “It’s not enough to just have the infrastructure, we have to be flying it,” he said. It will also look to parcel out the PBN operations on a case-by-case basis for each airport. “You pick the tools that are right for the job you have to do.”

DeCleene hopes to have the 15-year strategy completed by the end of the year for the NextGen advisory committee to review, which, as with PBN, will allow for a certain amount of flexibility. “We need to build into our strategy that we’re going to get smarter over time,” said DeCleene.

While Data Communications (Data Com) are currently not operating under a performance-based standard, DeCleene notes there is a very active conversation along the lines of applying a performance-based standard.

“For Data Communications, interoperability is an absolute necessity. Data Com was designed to allow the ground and the air to talk to each other. It is not performance based in that sense, it is interoperability driven and all of its standards and execution is built around specific technologies,” DeCleene said.

The tables may be turning for Data Comm, however, with the FAA currently taking up an initiative to see if there is room for performance-based implementation of the radio link for Data Comm, which, at its current point, requires VDL Mode 2 technology to connect to the FAA’s network it is rolling out alongside prime contractor, Harris Corp. This may enable aircraft equipped with Future Air Navigation System (FANS 1/A) capability operating with legacy tech such as VDL Mode 0, ACARS, SatCom, etc., to use their existing technology to access the physical layer and send Data Comm.

“Can we open the door to say, ‘it doesn’t matter what radio you hop over for your Data Comm, as long as the performance requirements are met,’” said DeCleene.


In the vein of surveillance, Automatic Dependent Surveillance-Broadcast (ADS-B) Out technology is what DeCleene calls a “half performance-based and half technology-based” solution. He recalls that the technology requirement for a transponder or Universal Access Transceiver (UAT) to transmit the signal is a “prescriptive, old school rule.”

“That’s not performance-based, you can’t invent new technology; you must use a transponder 1090 MHz extended squitter, down to the precise bit pattern and pulse modulation technique where you must us a UAT modulation. Why do we do that, why do we not use a performance-based regulation? Because someone is listening to what you are transmitting. So it’s important to keep in mind not everything can be performance-based and sometimes interoperability drives us to be more prescriptive, so it’s not a panacea,” DeCleene said.

What does allow the regulation to be performance-based, however, is the quality/accuracy metrics of the navigation solution (NIC, NAC, and SIL) around the day that the operator sends them.

“We don’t care where you get your quality metrics… I don’t really care if you have a genie, it doesn’t really matter as long as the information is correct and you are appropriately characterizing the quality of the information,” said DeCleene. “That is a very intentional structure of that regulation to allow it to be performance based.”

DeCleene admits, however, that thus far the equipage numbers for ADS-B Out are far under where the FAA would like to be, but that the performance-based area of the regulation may help to work through some of the stalling they have seen in implementation.

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