‘Green needles’

The official guidance even enables this wholesale switch to satellite-based navigation. A switch that’s been in high gear ever since the first panel-mounted GPS unit—Garmin’s GPS 155—was certified in 1994. In fact, the practical test standards (PTS) and airman certification standards (ACS) for the instrument rating speak only of demonstrating proficiency in precision and nonprecision approaches.

The current guidance lets an instrument rating candidate pass a checkride flying a mix of approaches that could include only one non-GPS approach, say, a VOR approach. But the other approaches could be a nonprecision RNAV (GPS) approach and an RNAV (GPS) approach with LPV (localizer performance with vertical guidance) having a decision altitude (DA) at or below 300 feet. These LPV approaches are considered precision approaches for checkride or instrument proficiency check purposes, even though many believe that ILSs still rule when it comes to precision approaches. When it comes to checkrides and IPCs, pilots can come away demonstrating minimal “green needle” (VHF) skills.

Bottom line: Although most flight instructors and flight training companies are diligent in teaching VOR, ILS, and localizer procedures to proficiency, strictly speaking it’s possible to meet today’s certification standards by learning GPS-only procedures. And the FAA’s plan to eliminate many VORs to create a minimum operating network (MON) emphasizes the increasing prominence of GPS navigation in the years to come.

All of this goes a long way to diminish the perceived utility of VHF-based navigation. It’s easy to understand. GPS navigation equipment is highly accurate, provides a wealth of capability and information, and can be intuitive to operate—once you’ve come to terms with the avionics manufacturers’ “knobology.” But many are concerned about an overreliance on GPS. According to traditional aeronautical engineering principles, single-point failures are to be avoided at all costs. In this case, if the GPS system should somehow become unreliable, or fail, the VHF-driven MON would be the backup.

Today’s sophisticated cockpits may have it all, but if history teaches us anything, it’s to be prepared for the unexpected.There are several ways GPS could let us down. Our onboard GPS equipment could malfunction. GPS signals could be jammed by aggressors hoping to disable tracking by military weapons—or our own military could jam signals in practice exercises. GPS satellite malfunctions could cause outages, and solar storms could affect accuracy. Recent news coverage following Russia’s practice destruction of one of its dead weather satellites—creating a 1,500-particle debris field—hints at expanding threats in a new kind of space warfare. Evidence suggests that Russia and China are constantly attacking U. S. satellites using lasers, jammers, and cyberbreaches.

To keep us aware of signal disruptions, the FAA publishes GPS notams. They’re worth checking. You can see them in published notams, or you can view notams.aim.faa.gov/notamSearch, click on the “location” dropdown menu, select the “predefined queries” entry, hit the “GPS Notams” button, and then the search bar. In airplanes with glass cockpits, a degradation or loss of GPS signal integrity should also be annunciated on a multifunction or other display, giving you an instant alert of a signal issue.

Let’s say you’re flying in instrument conditions and entering an area where GPS jamming exercises are in effect, and the approach you had planned to use is unavailable. You need to navigate away from the area, or perhaps land. What’s your Plan B? Calling ATC for a new clearance is an option, but that clearance may include a rerouting via Victor airways (the “V” stands for the “V” in VHF) followed by a clearance to fly an ILS or VOR approach to minimums. Are your VHF interception and tracking skills rusty after years of flying with GPS on direct routes to GPS-only approaches?

If you receive AOPA Pilot with the added Turbine Edition content, you probably recognize Neil Singer’s name. He writes the “Mentor Matters” regular series of articles. Singer is a high-time designated pilot examiner who specializes in recurrency and mentoring flights in technically advanced piston aircraft and light- and mid-size jets. He likes to check on pilots’ non-GPS navigation skills by simulating an U.S. Air Force “jamming” exercise, and then disabling a cockpit’s GPS-driven features. Those flying airplanes with three big screens are in for a surprise. He deprives his charges of synthetic vision, present position, moving maps, GPS-based pseudo-distance measuring equipment, terrain awareness warning system, and—of course—GPS nav guidance, including flight plan information.

Now it’s time for green, not magenta needles. And for calling up VORs and other VHF navaids to comply with a clearance to intercept and track the outbound course of a VOR or ILS approach, followed by a procedure turn or other course reversal, an intercept and tracking of the inbound course, along with a descent to minimums. Even though he allows pilots to use their autopilots, Singer says only about a third of the pilots can successfully manage the drill.

It’s like instrument flying in the 1970s. Back then, vacuum instruments and a single nav/com were standard-issue. If you had dual VOR heads, a heading bug, a Stormscope, and a wing leveler you had it made. Now all that’s history. Today’s sophisticated cockpits may have it all, but if history teaches us anything, it’s to be prepared for the unexpected. Some lessons from the 1970s still have value—if we keep them in mind.

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