Performance-Based Navigation Is Gaining Momentum

 - December 2, 2012, 3:25 AM
On a 2000 flight into Juneau, Alaska, AIN saw firsthand the value of RNP. Commencing from the south above 10,000 feet, the aircraft flies a straight descent path along the center of Gastineau Channel, with a 30-degree left turn at 500 feet onto final for Runway 26.

At ICAO’s General Assembly of world aviation nations in 2010, individual member states were requested to commit to national performance based navigation (PBN) implementation plans covering their en route and terminal airspace, plus approach procedures with vertical guidance (LPV/APV) for all their instrument runway ends–as primary or back-up for precision approaches–by 2016, with 70 percent completion targeted by 2014.

By the time of ICAO’s PBN Symposium in Montreal this fall, 110 of the world’s 147 nations had made that commitment, thereby including most of the relevant global airspace and just about every major and midsize airport.

By any measure, this was an unprecedented level of support to an un-mandated ICAO request that most operators invest in new avionics equipage by 2016 at the latest. By comparison, operator investment in, say, the FAA’s 2020 ADS-B avionics mandate appears to be sluggish. The difference lies in just one word: benefits. PBN promises–and delivers–enhanced safety, shortened routes, continuous climbs and descents, reduced fuel burn and emissions, noise abatement and increased airspace capacity and route flexibility leading to eventual 4-D operations.

The benefits are not only for pilots. They also affect aircraft operators, controllers, ANSPs, regulators, airspace planners, aircraft manufacturers and airports (and their non-flying neighbors), while PBN will dovetail into ICAO’s growing block airspace concept (see AIN, November 2011, page 52).Most of aviation’s “alphabet” organizations, including IBAC, IATA, Ifalpa, Ifatca and IAOPA, have endorsed ICAO’s proposal.

The key to the widespread industry acceptance of a universal PBN suite is that it embraces a wide range of standardized procedures from SBAS Lnav through LPV, and on to basic GNSS RNP through to its most demanding authorization required (AR, which has replaced special aircraft and aircrew authorization required [SAAAR]) applications that typically include radius-to-fix (RF) curved segments and track-keeping “containment” values as low as RNP-0.1 nm. It will also bring welcomed international uniformity to procedure descriptions and their characteristics, such as in upgrading Europe’s BRnav and PRnav to PBN standards.

In October, ICAO’s PBN Symposium in Montreal drew more than 400 attendees representing virtually all aspects of the aviation industry, from Europe, China, Japan, Brazil, South Africa, Australia and Canada, each of which, plus several other nations, have active PBN procedures in place.

Corporate Operations

The symposium included presentations from a wide range of industry participants, but prior commitments prevented two important industry members from attending. These were the representatives of the corporate aviation and ATC communities, both of whom are at the cutting edge of new technology applications, yet each sometimes find themselves handicapped in applying in mixed environments the full operator and traffic handling advantages that are potentially available. It’s often–and quite correctly–said that high-end corporate aircraft have more advanced avionics capabilities than the vast number of airline jets built before the Airbus A380 and Boeing 787, and many new corporate jets can match even their capabilities. Yet Part 91 aircraft, however well equipped, are excluded from the FAA’s Rnav visual flight procedures (RVFP), thus calling into question the agency’s “best equipped, best served” mantra. In addition, at locations such as Chicago Midway (MDW), the FAA has no efficient way of identifying Part 91 aircraft equipped for RNP/AR, making use of the RNP/AR procedures at MDW by Part 91 unlikely.

Bob Lamond, NBAA director of air traffic services and infrastructure, has long been insistent that as we move toward NextGen, “We must ensure that the FAA provides a level playing field that balances the needs of all operators by allowing equal access to airspace and airports. Lamond also suggested, “We have to remember that while “performance-based navigation” is a common reference used by aviation stakeholders, the whole of NextGen, not just its ‘navigation’ applications, will ultimately be performance based, so the broader acronym PBO, for ‘performance-based operations,’ is where we need to remain focused.

Performance-based thinking has also turned a money-losing South African airport into a profitable enterprise. At Pietermaritzburg, the capital of Natal State, the airport’s single, NDB-served runway lies within a bowl surrounded by high ground, with its prevailing southeasterlies frequently bringing low ceilings and visibilities. Scheduled operations were not cost effective, due to frequent diversions, causing decreasing passenger numbers, a decline in aircraft movements and contraction in the local economy. In 2010, RNP Approach procedures were introduced, resulting in schedule reliability, increased passengers, the arrival of a second air carrier, airline upgrading from turboprop twins to larger, four-turbofan BAe RJ85s, lower fares, a rejuvenation of the airport’s related aviation service businesses and an unprecedented waiting list for hangar space.

Yet despite the current acceleration of commitment to PBN, it’s still worth remembering the long route to industry’s acceptance of the concept, originally proposed in 1996 by Alaska Airlines Capt. Steve Fulton, now a senior GE Aviation executive. AIN’s first exposure to Fulton’s RNP work was a jump seat flight into Juneau, Alaska, in 2000 that, on a VMC day, was deeply impressive, as we descended below the 3,000-feet-high rocky walls of the Gastineau Channel on either side of the aircraft, on our way down to a 30-degree left turn onto a DH final at 500 feet. And if proof of PBN’s enhanced safety were needed, that pioneering RNP procedure–the world’s first–has been repeated every day since then, in good weather or bad, with never a single incident, as have its many derivatives in use worldwide today.