IN FOCUS: Bringing NextGen avionics to the business-jet set

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Teterboro airport in New Jersey, just 27km (17 miles) northwest of New York City's financial district, is to business aviation what Atlanta Hartsfield is to airlines - the busiest airport in the USA. With 122,340 operations logged between October 2010 and September 2011, Teterboro is more than twice as busy as business aviation's number two airport - nearby Westchester County, with 60,494 operations over the same period, according to US Federal Aviation ­Administration statistics.

Unlike busy hubs like Atlanta, however, ­Teterboro itself has not traditionally been a focus area when it comes to the marketing of next-generation air transportation system (NextGen) bedrock components, such as automatic dependent surveillance-broadcast (ADS-B), technologies that can boost capacity, reduce delays and increase situational awareness and safety. ADS-B is now active in the Gulf of Mexico - largely to help helicopter operators with constant surveillance and to avoid delays in instrument flight rules weather.

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 © Theo Van Vliet

Teterboro: busy business-aviation hub

However, business aviation has not been the focus of a directed government programme to demonstrate NextGen results as a way to get operators to voluntarily invest in equipment in advance of a 2020 mandate for ADS-B "out" equipment, which transmits information from the aircraft to ground ­stations and to other ADS-B-equipped aircraft

"Many people in the industry, many [business aviation] flight operations managers have read about ADS-B, but they conceptually don't understand what it means to them," says Greg Sumner, original equipment manufacturer (OEM) and integrator sales manager for ACSS.

A joint venture between US-based aerospace manufacturer L-3 and France's Thales, ACSS builds safety avionics equipment including transponders and ADS-B equipment. Sumner - who previously worked in ACSS's SafeRoute group, and before that flew Bombardier Learjets out of Teterboro - had a keen interest in seeing how the company's products could help at a facility where he personally experienced the effects of higher-density airline traffic heading to and from Newark and the other New York airports.

Given that Newark, particularly in summer months, can be the most delayed arrival and departure airport in the USA, it follows that Teterboro is capacity-limited and delay-abundant. In terms of NextGen, ACSS is perhaps best known for its SafeRoute suite of ADS-B-based surveillance applications, developed originally for launch customer UPS. Along with flightdeck computers running ACSS software, SafeRoute includes an electronic flight bag (EFB) function that displays ADS-B "in" traffic information, maps and other data that supporters of the technology say will allow for cockpit-centred traffic control and self-separation. The practice will be made possible precise wide area augmentation system-enhanced GPS position information. This is then broadcast by ADS-B "out" equipped aircraft.

ADS-B "in" features a receiver that brings the position and associated aircraft identification information into the cockpit for a variety of uses. For UPS, the traffic information is shown on a universal cockpit display of traffic information (U-CDTI) hosted on an Astronautics EFB, though other airlines can choose ­different EFBs or display methods. ACSS SafeRoute applications for airline customers to date include merging and spacing, in-trail ­procedures (ITP), CDTI-assisted visual separation (CAVS) and surface area movement ­management (SAMM). Why not for business aviation, and why not at Teterboro?

In 2009, Sumner contacted the National Air Traffic Controllers Association to get first-hand knowledge of the issues at Teterboro from controllers working there. "One of the problems at Teterboro is where it's located - on the final approach for runway 22 at Newark. There's not a lot of room to operate."

For controllers, this translates into labour-intensive departure and arrival corridors for the business jets that must be weaved with airlines heading to Newark just 19km (10nm) to the south.

CHANGING APPROACHES

He found that a popular offset-angle very high frequency (VHF) omnidirectional radio (VOR) instrument approach into Teterboro had been discontinued, cutting capacity by 20% - from 75 operations per hour down to 60.

"It caught my attention," Sumner says. "That approach gets the business jets out of the way [of Newark traffic] and into the airport." Controllers explained that they stopped using the approach after the 2008 economic downturn - when traffic had let up anyway - because of the high workload it required on their part. "It was a lot of instructions from controllers for speed and guidance," he adds. "Our idea was to use CDTI traffic separation to give the crews better ability to space off the traffic ahead of them and let the controllers focus on other things."

The practice could help both on the arrival and departure corridors to Teterboro, he says, in addition to boosting safety by improving situational awareness on and above the airport, thanks to having a highly accurate own-ship position overlaid on the 2D airport diagram of the CDTI.

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ACSS's SafeRoute suite of ADS-B-based surveillance applications can be hosted on an Astronautics EFB

Experience from a small set of operators had shown the validity of the idea. Sumner says UPS, which now has 11 aircraft equipped with SafeRoute, has found that voice transmissions when using merging and spacing on average decreased, and the cargo carrier eventually plans to equip its entire fleet. For departures, Sumner believers CAVS could be used to allow aircraft to self-separate, based on a time delay between aircraft. For example, during pre-departure clearance the tower would tell a Learjet pilot to fly a standard instrument departure (SID) course profile, while maintaining a 60s buffer behind a leading aircraft - with unique a identifier - on the same SID.

With SafeRoute's self-spacing functions, the pilot sees the position and identification of the leading aircraft on the CDTI, and has a separate indicator in the forward field of view showing real-time target speeds. Like UPS, passenger airlines are beginning to dabble in the technology, primarily with government help. US Airways, under a $6 million FAA programme, tested out SafeRoute's surface indicating and alerting capabilities at Philadelphia international airport in late 2009, with a temporary installation on one Airbus A330 and one ACSS aircraft.

The carrier is now in the process of ­installing ACSS's TCAS 3000SP surveillance processors, loaded with SafeRoute SAMM on 20 Airbus A330s. SAMM operations with SafeRoute will begin in January, ACSS says, with interval management and ITP added to the 3000SP processors by summer 2012.

The FAA also gave JetBlue ­Airways $4.2 million to install TCAS 3000SP equipment in 35 A320s. Initially the ACSS systems will be used in ADS-B "out" mode to fill in ground radar coverage gaps - allowing for more direct routes in the Caribbean - but later will begin using the ADS-B "in" SAMM function for airport operations in Boston and New York JFK. Sumner says the retrofit work will be complete in the second quarter of 2012.

PERSONAL SPACE

ITP is particularly beneficial for oceanic flights, where remote surveillance currently requires large in-trail spacing due to position uncertainty, and flight-altitude changes to net more favourable winds require numerous radio calls to co-ordinate. This is because aircraft do not have accurate position estimates of nearby traffic using traditional (non-ADS-B) transponders. Delta Air Lines plans by the end of the year to begin using ACSS ITP applications, with British Airways to do the same by early 2013, as part of Eurocontrol's "CASCADE" ADS-B programme for Europe. United Airlines, under an FAA programme, is installing Honeywell surveillance equipment for ITP trials as well.

Recent moves that bring business aviation into the advance planning phase of future pilot projects could in theory directly benefit the sector. The FAA, under the auspices of the Radio Technical Commission for Aeronautics, set up a NextGen advisory committee (NAC) in September 2010, charged with coming up with recommendations for "outcome-based" ­performance metrics for NextGen projects. Steve Brown, senior vice-president operations and administration for the National Business Aviation Association (NBAA), is co-chair of the NAC subcommittee and work groups.

In the NAC's initial set of recommendations, issued in September, Teterboro is specifically mentioned regarding incentives to get operators to equip required navigation performance (RNP) avionics. A navigation technology, RNP provides customised, precise approaches to an airport, but is not related to advanced ­surveillance practices such as self-spacing. "In general, operators of these aircraft are motivated to equip their aircraft to gain the advantage in time saved through reduced track miles," the group writes of the possibility of the FAA building new RNP instrument approaches with curved segments into Teterboro and several other key business aviation airports.

US-headquartered Honeywell - an FAA-approved provider of RNP procedures to the industry - has received FAA approval for one such approach it had developed, with the required aircraft components and training, into the corporate headquarters airport in Morristown, New Jersey. Teterboro is also likely to be the focus of recommendations from an FAA-chartered aviation rulemaking committee, tasked with defining a strategy for incorporating ADS-B "in" technologies - some of which SafeRoute is already demonstrating.

The committee's initial recommendations will likely include some "low-hanging fruit" with rapid results - one of which could be a test of ADS-B departure spacing at Teterboro. "[The] industry is telling the FAA they want this early in the NextGen programme," Sumner concludes.