An ILS that Requires GPS

You can still fly IFR in the U.S. without an IFR-approved GNSS (i.e., GPS), but being “slant G” (/G in the soon-to-be obsolete FAA domestic flight plan format) increasingly offers advantages, even if you fly only conventional procedures based on ground navaids. And sometimes an IFR-approved GNSS is required to fly even an ILS.

Consider the ILS Z OR LOC Z RWY 16R approach at Reno/Tahoe International Airport (KRNO). This procedure is not an Authorization Required approach–RNP doesn’t appear in the title, and you won’t find that restrictive note on the chart. (For more information about RNP procedures, see RNP Procedures and Typical Part 91 Pilots.)


But the equipment required notes for this ILS approach include “RNAV-1 GPS required.”

A review of the plan view and missed approach track show why GPS is necessary to fly this procedure.


First, you need GPS to fly transitions from most of initial fixes, which are RNAV waypoints marked by a star symbol.


Only LIBGE, directly north of the runway, is a non-RNAV IAF.

For example, HOBOA, KLOCK, BELBE, and WINRZ are all RNAV waypoints that serve as IAFs or IFs. Now, NORCAL Approach might provide vectors to the final approach course, but if you want to fly this procedure you should be prepared for a clearance direct to one of those fixes (see Avoiding the Vectors-to-Final Scramble).

Note also that entire missed approach track requires use of GNSS.

Two of the transitions are of special note. The “arcs” that begin at ZONBI and SLABS are radius-to-fix (RF) legs that are part of the transitions that begin at HOBOA and KLOCK. Each of those fixes is distinguished by the notes “RNP-1 GPS REQD” and “RF REQD.”

The first note means that your GPS must meet the RNP 1 standard, which is used for terminal procedures such as SIDs and STARs, the initial phases of approaches, and missed-approach segments. (For more information about RNP, see RNP Procedures and Typical Part 91 Pilots.)

Until recently, RF legs were included only in Authorization Required (AR) procedures. But as I explained in Garmin GTN Avionics and RF Legs, certain RF legs are now available if you have an appropriate GNSS navigator, updated system software, an electronic HSI, and other equipment. Some limitations on flying such RFs also apply, as described in that earlier post.

Suppose that you choose the less intimidating ILS X or LOC X RWY 16R to the same runway. A review of the notes and the plan view shows that even this conventional-looking ILS also requires RNAV 1 GPS, both to fly the transition from WINRZ and the missed approach track.




New Edition of the Aeronautical Chart Users Guide

FAA has published a new edition of the Aeronautical Chart Users Guide, effective October 12, 2017.

The new edition is available as a free PDF at the FAA website, here. This update includes a What’s New section, starting on page 5, that highlights changes from the previous edition.

The guide explains the symbols and terms used on VFR and IFR charts published by the FAA, including sectionals, IFR enroute charts, and terminal procedure charts (SIDs, STARs, and IAPs).

Clearances to GNSS Equipped Aircraft Below the MEA

FAA recently updated Air Traffic Control (JO 7110.65W) to allow IFR clearances to GNSS (i.e., GPS) equipped aircraft on airways below the published minimum en route altitude.

N JO 7110.741, published on September 25, 2017 (now incorporated in Air Traffic Control paragraph 4-5-6), explained that:

This notice…allow[s] IFR certified Global Navigation Satellite System (GNSS) equipped aircraft to be cleared below published Minimum En Route Altitudes (MEA)…

The notice explained that:

MEAs are based in part on ground-based navigational aid reception. The advent of satellite technology provides the opportunity for lower minimum altitudes along certain airways, allowing more altitudes to be usable for more aircraft. This change will facilitate IFR certified GNSS equipped aircraft to fly below published MEAs, but no lower than Minimum Obstruction Clearance Altitudes, Minimum IFR Altitudes, or Minimum Vectoring Altitudes, regardless of radar coverage. This would apply to all applicable airways, rather than being limited to those published with GNSS MEA minimums.

Note that the rule (in 14 CFR §91.177 Minimum altitudes for IFR operations) about flying at the MOCA  when you are using VORs still applies:

For aircraft using VOR, VORTAC or TACAN for navigation, this [i.e., flying at the MOCA] applies only within 22 miles of that NAVAID.

The low-altitude en route chart below points out examples of MEAs and MOCAs. (Click here to see the chart at


For example, along a segment of V187 between MOG and MSO, the MEA is 13000. The MOCA is 9900. There is no published GPS MEA (which would appear in blue with a G appended to the altitude). But if you are flying with an IFR-approved GPS, ATC could clear you to 9900, if, for example, you encountered ice.

Similarly, along V120 east of MLP, the MEA is 13000 and the MOCA is 9600, potentially giving you more than 3000 feet to work with if necessary.

Note, however, that not all airway segments have published MOCAs. For example, the only published IFR altitude between PUW and MLP is the MEA of 9100. You still might be cleared below that MEA if ATC has a lower minimum IFR altitudes or minimum vectoring altitudes available in that area, but those altitudes are not typically published on charts that pilots use.* You would just ask for a lower altitude, and the controller could clear you to the appropriate MVA or MIA.

The updated FAA handbook specifically notes that controllers may clear you to an MVA or MIA, but they must also issue lost communications instructions:

(a) In the absence of a published MOCA, assign altitudes at or above the MVA or MIA along the route of flight, and

(b) Lost communications instructions are issued.

*You can download MVA and MIA charts as PDFs from the FAA website, here. But at present, these charts are not available in a format that allows for easy integration with apps that pilots typically use or straightforward comparison with other aviation charts.

FAA Proposes Cuts to Circling Approach Minimums

The FAA has announced the early stages of plan to evaluate and then cut the number of circling minimums published for instrument approaches. According to a notice in the Federal Register on October 6, 2017:

In early 2015, the FAA requested the RTCA’s Tactical Operations Committee (TOC) with providing feedback and recommendations on criteria and processes for cancelling instrument flight procedures. Among the many recommendations provided by the TOC were criteria on how to identify circling procedures that would qualify as candidates for cancellation. As of the beginning of 2017, there are approximately 12,000 IAPs in publication, and there were nearly 10,600 circling lines of minima. Circling procedures account for approximately one-third of all lines of minima in the NAS.

In its continued effort to right-size the NAS through optimization and elimination of redundant and unnecessary IAPs, the FAA proposes the following criteria to guide the identification and selection of appropriate circling procedures to be considered for cancellation…

Proposed Policy

All circling procedures will continue to be reviewed through the established IAP periodic review process.As part of that review process, the FAA is proposing that each circling procedure would be evaluated against the following questions:

—Is this the only IAP at the airport?

—Is this procedure a designated MON airport procedure?

—If multiple IAPs serve a single runway end, is this the lowest circling minima for that runway? Note: If the RNAV circling minima is not the lowest, but is within 50′ of the lowest, the FAA would give the RNAV preference.

—Would cancellation result in removal of circling minima from all conventional NAVAID procedures at an airport? Note: If circling minima exists for multiple Conventional NAVAID procedures, preference would be to retain ILS circling minima.

—Would cancellation result in all circling minima being removed from all airports within 20 NMs?

—Will removal eliminate lowest landing minima to an individual runway?

The following questions are applicable only to circling-only procedures:

—Does this circling-only procedure exist because of high terrain or an obstacle that makes a straight-in procedure unfeasible or which would result in the straight-in minimums being higher than the circling minima?

—Is this circling-only procedure (1) at an airport where not all runway ends have a straight-in IAP, and (2) does it have a Final Approach Course not aligned within 45 degrees of a runway which has a straight-in IAP?

Further consideration for cancellation under this policy would be terminated if any of the aforementioned questions are answered in the affirmative. If all questions are answered in the negative, the procedure would be processed as described in the following paragraph.

Flying the Extra: Seattle to Las Vegas

Each year around the end of September, I fly the Extra 300L from Boeing Field (KBFI) in Seattle to its winter base at Boulder City, NV (KBVU) outside Las Vegas. The video below shows highlights from the flight this year. Enjoy the dramatic changes in the landscape from the well-watered Puget Sound region to the desolate desert in southern Nevada.

BruceAir-Extra-009.jpgPhoto: Felix Knaack

The Extra isn’t designed for long-distance journeys, and I have to make two fuel stops to complete the journey of about 900 nm (1670 km). I usually stop at Bend, OR (KBDN) and Yerrington, NV (O43). The flight itself typically requires 5.5 – 6.0 hours; with the two stops the total block time is usually about 8 hours.

You can view the route that I flew at here.

FAA Changing Notes on Instrument Charts

The FAA is gradually changing notes on instrument procedure charts (SIDs, STARs, and approaches) to consolidate and clarify equipment required and PBN-related information.

AOPA has published a detailed summary with background on the changes here.

The AOPA summary also includes tables that can help pilots who use Garmin equipment understand the capabilities of the avionics installed in their aircraft.


FSS Reducing RCO Network

The network of remote communications outlets (RCO) used by FSS is shrinking, in part because of the elimination of Flight Watch, but mostly due to a dramatic drop in radio contacts between pilots and FSS.

According to documents at the FSS website:

Our goal is to retain a minimum of 90% of the current RCO coverage at 1,000 feet AGL. Graphical representations of RCO coverage areas at different altitudes are available on our website…The removal of the frequencies is scheduled to begin in the fall of 2017 and be completed by the end of 2018.

FSS plans to retune some RCOs from 122.0 (the frequency formerly used for Flight Watch) to the most common FSS frequencies (122.2, 122.3, 122.4, 122.5 and 122.6).

To see a list of RCOs and those scheduled to be decommissioned, open the Microsoft Excel workbook available at the FSS website, here.

More Evidence of Adoption of Apps

According to an FAQ document on this topic (PDF), the number of radio contacts with FSS has dropped from about 4.5 million in 1993 to about 321,000 in 2016.

If you want evidence that pilots have rapidly adopted apps and avionics that provide near-real-time weather in the cockpit, and that they use web-enabled devices and services to brief and file flight plans, this graph may be exhibit one.