Twenty years ago, the FAA commissioned the Wide Area Augmentation System (WAAS), opening the door to satellite-based GPS navigation with accuracy, integrity, and consistent availability for an array of business and general aviation.
Leading as much as then, WAAS had come under scrutiny—and criticism—after encountering several years of delays and mushrooming costs. Even so, groups resembling the Aircraft Owners and Pilots Association strongly backed it.
And now, when you are a business aviator and never using WAAS, then you definitely can count yourself in a minority. Most business aircraft rolling off the production line now are equipped to fly RNAV approaches with WAAS localizer performance with vertical guidance (LPV) minima.
Avionics repair shops also proceed to upgrade aging jets, turboprops, and IFR-capable piston singles and twins with WAAS LPV, often as a part of major full panel upgrades. It will probably cost $20,000 to $30,000 to upgrade a small aircraft with WAAS LPV and more like $200,000 to $300,000 for a business jet, in response to several avionics repair shops.
What do general aviation aircraft owners get for the cash? They get access to precision-like approaches with greater than 4,100 WAAS LPV procedures that may, in lots of cases, match Category 1 ILS minimums right down to 200 feet. LPV serves nearly 2,000 airports, including greater than 1,200 without ILS.
WAAS provides an accuracy of two to 4 meters for horizontal position by providing corrections to GPS from greater than two dozen precisely surveyed ground stations. These corrections are broadcast as much as geostationary orbit satellites after which sent from there to avionics aboard aircraft.
The Safety Profit
In keeping with the FAA, WAAS provides pilots with more stable vertical guidance for approaches and enhances safety in all weather conditions. The Flight Safety Foundation points out that controlled flight into terrain accidents are significantly reduced by vertically guided approaches. ILS approaches might be affected by bends within the signals that may result in a missed approach, the FAA noted.
WAAS localizer performance (LP) procedures provide for lateral accuracy much like ILS for approaches where terrain or obstructions don’t permit LPV. The FAA says some manufacturers include an advisory glideslope so pilots can fly a stabilized descent to the minimum descent altitude.
There are 734 WAAS LP approaches to 734 runways at 537 airports—most of which don’t have ILS. These RNAV approach procedures without vertical guidance have LP minima that can be helpful when there isn’t a precision-type approach available at an airport.
There are just one,290 ILS approaches within the U.S.—nearly one for each three LPVs.
NBAA points to the advantages of the lower minimums provided by WAAS. “Our members value the precision-like minimums WAAS technology brings to the table. Many aircraft owners have equipped to reap the benefits of the capabilities and lower minimums at many airports across the country that aren’t currently served by an ILS,” said NBAA senior director of air traffic services and infrastructure Heidi Williams.
The Costs
When the FAA announced in July 2003 that it had commissioned WAAS, there have been only 500 approaches with WAAS that had been certified at 200 airports. By 2003, the system had a value of roughly $2.5 billion, including the then-estimated lifecycle costs through 2020 (which just so happened to be when the pandemic began). This was up from the initial 20-year lifecycle cost estimate within the early Nineties, before a $1.4 billion contract had been awarded.
To this point, the prices incurred to develop and operate WAAS have reached nearly $3 billion, of which $2.7 billion is development costs, including satellite leases. The FAA said it costs $90 million to $110 million per yr to operate and sustain the WAAS system.
On the time WAAS was commissioned, it provided an accuracy of 1 to 1.5 meters compared with 7 to 10 meters (vertically and horizontally) obtained from GPS without augmentation.
The U.S. Air Force is modernizing GPS and has already launched six out of 10 GPS Block III satellites which are expected to enhance GPS accuracy by thrice. These satellites broadcast on three frequencies—L1, L2 and the newer L5. Nevertheless, the L5 signal won’t grow to be fully operational—expected later this decade—until it’s broadcast from 24 satellites; currently, it’s being broadcast from 17 satellites.
In 2022, Raytheon Intelligence and Space was awarded an indefinite quantity contract with a ceiling of $375 million over the subsequent decade for technical refresh and dual-frequency (L2 and L5) operation upgrades to WAAS. This may include more modern and sustainable processing, system security, and network architecture while adding dual frequency service in 2028.
The L5 frequency is designed to enhance accuracy, integrity, and availability using dual-frequency-enabled WAAS receivers. Dual frequency (L2 and L5) will likely be especially helpful during ionospheric disturbances, including solar storms. The FAA adds that dual frequency will enable further expansion of WAAS LPV service in Alaska, Hawaii, Puerto Rico, Canada, and Mexico.
Legacy avionics might have a firmware or software upgrade to reap the benefits of the L5 WAAS frequency when it goes fully operational, in response to Sam Pullen, a senior researcher on the Stanford GNSS laboratory. He holds a doctoral degree in aeronautics and astronautics from Stanford and an undergraduate degree from MIT.
Legacy WAAS equipment users will find a way to get the identical performance they’re getting now by counting on the unique L1 frequency.
Standalone GPS (without using WAAS corrections) can be adding the L5 frequency for aeronautical and other uses. The primary six of the initial 10 GPS III satellites at the moment are in orbit, and the opposite 4 will likely be launched by 2026 if things go in response to plan. Standalone GPS III receivers will find a way to counter ionospheric delay to cut back satellite error. The GPS ground control system is being upgraded, and this work must be accomplished before dual-frequency (L1 and L5) operations can begin.
“The operational profit will likely be higher availability, so that you usually tend to find a way to fly an approach to completion than before,” said Pullen. The boundaries on worst-case errors will likely be reduced, increasing each accuracy and availability. WAAS and other satellite-based augmentation systems (SBAS) can also provide corrections for the European Galileo system signals and potentially other Satnav systems. The European EGNOS version of SBAS already supports using GPS and can add Galileo support together with Galileo’s second frequency on E5a (the identical as GPS L5).
Aviation isn’t the one community using WAAS, which can be present in agriculture, surveying, and maritime sectors. In aviation, regional airlines SkyWest and Horizon Air have installed WAAS on their aircraft, and Delta, Airbus, and Boeing are moving ahead with equipage.
At DeltaFox Aviation at Manassas Regional Airport in Virginia, a Part 145 repair station, co-founder Charles Schefer still continuously installs avionics to upgrade general aviation aircraft to fly WAAS LPV approaches. DeltaFox is a dealer or service center for Cirrus, Textron, Garmin, Avidyne, and Aspen Avionics, amongst others.
“I feel like 70 percent of the overall aviation fleet is already upgraded to fly WAAS approaches, and a lot of the latest business aircraft rolling off the production line [are] also already equipped,” Schefer said.
Mass Equipage
There are greater than 200,000 lively general aviation aircraft, in response to the FAA, which cited greater than 140,000 WAAS-equipped aircraft within the NAS in a June 2021 presentation.
The FAA said 160,000 aircraft are equipped worldwide. The ADS-B mandate spurred WAAS equipage since it is the one navigation source that meets those requirements.
“Nevertheless, I see numerous older jets that aren’t yet equipped and to upgrade one to fly LPV costs so much,” Schefer said. “This often pertains to the constraints of the autopilot, flight director, or other equipment currently installed.”
Older Collins Pro Line 21 avionics don’t support flying LPV approaches, and it could require a $20,000 supplemental type certificate (STC) to essentially trick it into considering it’s flying an ILS so it might probably display the approach parameters. Universal FMS and Garmin GTN avionics are WAAS-capable.
In some cases, the needles on a display are color-coded so pilots can tell in the event that they are flying an ILS by seeing green needles, while magenta ones indicate flying a WAAS-guided approach.
Schefer did numerous Cessna Citation upgrades to WAAS LPV, but a lot of the aircraft in that product line have been outfitted. When an STC box shouldn’t be installed, the GPS is restricted to make use of for lateral navigation, so it isn’t possible to fly an LPV approach with vertical guidance. Smaller general aviation aircraft flown mostly under VFR are seldom equipped because they won’t be flying WAAS LPV or LP approaches. “It wouldn’t make any sense,” Schefer said.
Schefer also operates a Part 135 charter business and recalls one trip he needed to cancel with a Cessna Citation CJ2 to an airport without ILS. He said the previous owner of the aircraft installed WAAS but not LPV capability, so he couldn’t use the LPV on the airport he was planning to fly to.
Bill Forbes, the director of avionics sales for Elliott Aviation, recounts a WAAS story that’s posted online at the corporate’s website. Elliott works on a big selection of business jets at three service centers within the Midwest, one in Texas, and one in Georgia. A number of years ago, an Elliott customer was flying on a Hawker 800 on a business trip from Nashville to Lambert International Airport in St. Louis, the town’s important industrial airport. The ILS was out and the Hawker 800 pilot executed a missed approach but saw a Cirrus land right after that. A diversion led to the aircraft owner missing the essential meeting in the town, and he ordered a WAAS LPV installation for the Hawker the subsequent day.
In Lynchburg, Virginia, Jason Moorefield runs an avionics shop at Freedom Aviation that maintains Liberty University’s fleet of coaching aircraft and does avionics installations for other customers. The shop has three other technicians. Moorefield does WAAS LPV upgrades to aircraft several times per 30 days, either as a standalone job or as a part of a brand new panel. He notes that small business aviators like WAAS LPV for moving into airports which are situated near the positioning of their day’s work but aren’t equipped with VOR or ILS.
He likes installing the GNC 355 all-in-one touchscreen GPS navigator with comm radios for light aircraft, which provides WAAS GPS navigation for LPV approaches. It pairs with chosen Garmin flight displays or integrates with a course deviation indicator for a low-cost installation. Garmin lists the value of the GNC 355 as $7,695. Moorefield works on some jets annually and says a WAAS LPV retrofit for a jet starts at $200,000.
While the FAA is enabling satellite navigation, it shouldn’t be giving up on maintaining ILS systems and a few VORs for resilience. Jens Hennig, vp for operations on the General Aviation Manufacturers Association, said some air navigation service providers in Europe are considering eliminating some ground infrastructure. He thinks this approach is short-sighted.
Hennig notes that the FAA investment in WAAS has already been made. “America has a beautiful belt and suspenders system [with WAAS and ground-based navaids including ILS],” said Hennig.
“Now we do need to speculate in teaching flight crews how one can fly in that environment [without ground-based navaids] when there are possibly some challenges in the longer term,” he said, but added: “WAAS is an excellent technology and the FAA continues to speculate in it.”
FAA is working on an ILS Rationalization Program to decommission some ILS systems at smaller airports equipped for WAAS LPV approaches. It has not decommissioned any ILS systems yet or announced what number of will likely be chosen. However the agency has shut down 164 VORs and can shut down 139 more at a rate of 20 per yr, ultimately leaving 590 running in its minimal operational network.
Evaluation, coordination, and approval of the ILS program are required to discover candidate systems before any decommissioning begins. The FAA has contracts arrange to exchange aging ILS systems with state-of-the-art systems. ILS will likely be retained at airports where air carriers operate and together with VORs to make sure resiliency during GPS outages.
In Tulsa, Oklahoma, Joseph Hensley upgrades numerous long-out-of-service turboprops that will have sat on a ramp somewhere for 10 or more years. He’s the avionics manager for Intercontinental Jet Service Corp. Hensley said his shop installs WAAS LPV capability in these older aircraft together with completely latest panels.
After purchasing the aircraft and installing latest avionics, the brand new owners could have $1.5 to $3 million invested. But for an airplane just like the Mitsubishi MU2 that may carry eight passengers with a single pilot at greater than 300 knots, the associated fee per flight hour could also be around $2,000 per hour with fuel consumption at 80 gallons per hour.
“It is smart why these refurbished aircraft are so popular,” Hensley said. An analogous latest turboprop aircraft would cost $7 to $15 million. Most of his customers are doctors, lawyers, and salesmen who depend upon these aircraft to grow their businesses.
Intercontinental is a licensed Mitsubishi and Piaggio service center. Hensley has upgraded 100 Mitsubishi aircraft and 40 Piaggios with latest avionics systems, including most with WAAS LPV. Plenty of these aircraft fly into small airports without ILS, so that they need WAAS LPV capability to get there.