On Dec. 30, 2009, Horizon Air Flight 2014 — a Bombardier Q400 twin turboprop — arrived at Seattle-Tacoma Airport using avionics with Wide Area Augmentation System (WAAS) enabled. It marked the first revenue-generating flight in the country to use the technology, which is seen as a less expensive, more accurate and more dependable alternative to ground-based precision navigation systems, such as ILS equipment. Later that day, another Horizon Q400 flight executed a Localizer Performance with Vertical (LPV) approach at Portland (KPDX). With low IMC prevailing and the ILS to Runway 10R out of service, the LPV approach was required to complete the flight. At the core of the Q400s' WAAS avionics installation is the WAAS-enabled UNS-1Ew Flight Management System (FMS) from Universal Avionics. Horizon is currently upgrading its fleet of 40 Q400s with the Universal FDSs. There are currently 1,884 WAAS approaches published, offering operators lower minimums and greater flexibility in airport choices, including available alternate airports for IFR flight planning.