Thursday, October 1, 2009
Recently, we’ve talked about the FAA’s NextGen Roadmap and many of the new tools that are being made available to us. Due to accuracy errors inherent to GPS, two methods have been created to augment the GPS signal to improve position accuracy from approximately 10 meters to two meters. One of the most promising NextGen technologies to accomplish this and support IFR domestic helicopter operations is WAAS, or wide area augmentation system. You may also hear WAAS referred to as a space based augmentation system, or SBAS, since the signal augmentation is broadcast from a geostationary satellite to a wide area, unlike its ground-based NextGen cousin LAAS, or local area augmentation system.
WAAS can provide a precise vertical path similar to an ILS known as localizer performance with vertical guidance (LPV). WAAS LPV approaches provide approach minimums similar to a Category I ILS along with signal monitoring and alerting to the flight crew. WAAS uses a system of ground-based wide area reference stations (WRS) that communicate clock and signal errors to a master reference station (MWS). The augmentation is uplinked to a geostationary satellite and broadcast to your WAAS-enabled GPS navigation receiver. Check out FAA’s Navigation Services website to discover more about the technology and get updates on the various satellite navigation programs at http://gps.faa.gov.
A new project based on a government and industry partnership has recently begun in New York City. This historic project is for the development of WAAS LPV vertical flight instrument approach procedures and a supporting IFR structure in arguably the most congested airspace in the country.
To learn more about the FAA’s plans for developing performance based navigation procedures, we spoke with Dave Peterson, the FAA’s GNSS operational implementation team lead in Washington. Peterson, an experienced helicopter pilot himself, provided a unique opportunity to better understand the projects he is leading. "The FAA and vertical flight community have come together in a government/industry partnership to address some of the significant issues associated with development of an integrated vertical flight IFR structure," he said. "The vertical flight community in the northeast region is committed to working with the FAA and NextGen technology in the application of proven space-based augmentation systems. This structure will support the development of a fully integrated helicopter IFR navigation system."
Peterson added: "Due to a lack of tailored vertical flight criteria, helicopter operators experience many common problems such as circuitous routing, excessive approach minimums, and lack of onsite weather reporting, which affects destinations and alternates. Even today, there is an absence of procedures necessary to minimize rotorcraft and fixed-wing interaction in today’s constrained airspace."
To gain a better understanding of the operational benefits of WAAS, I spoke with Ray Dauphinais, director and vice president of operations for CareFlite. The Dallas, Texas-based operator is the eighth oldest air medical transportation service in the nation and the second oldest in Texas. Dauphinais (76-36 Royal Blue) is an 11-year veteran of CareFlite and an avid proponent of WAAS, and specifically WAAS LPV approaches. CareFlite operates a fleet of A109 helicopters and has 18 FAA-approved instrument approach procedures (five WAAS LPV) at hospitals in Texas. "We require our pilots to obtain their ATP if they don’t already have one, as a condition of employment," he said.
Dauphinais went on to explain that his SOP for inadvertent IMC is to begin an immediate climb away from the ground and enter the IFR system. He is spearheading a project at CareFlite working with the FAA’s Satellite Navigation office to develop STCs and WAAS LPV approaches. The goal is to create a system of dedicated vertical flight airways and approaches to support all weather helicopter flight operations in the Dallas-Fort Worth area.
The next several years will be an exciting time for the helicopter community as we transition from legacy ground-based navigation aids designed primarily for fixed-wing use, toward a space-based system that provides opportunity for tailored, performance-based navigation architecture for helicopters.