AC 91-92: Pilot’s Guide to a Preflight Briefing

FAA has published AC 91-92: Pilot’s Guide to a Preflight Briefing (March 15, 2021), which:

…[P]rovides an educational roadmap for the development and implementation of preflight self-briefings, including planning, weather interpretation, and risk identification/mitigation skills. Pilots adopting these guidelines will be better prepared to interpret and utilize real-time weather information before departure and en route, in the cockpit, via technology like Automatic Dependent Surveillance-Broadcast (ADS-B) and via third-party providers. This AC provides guidance for required preflight actions under Title 14 of the Code of Federal Regulations (14 CFR) part 91, § 91.103, which states, “Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight.” This AC will also encourage pilots to utilize Flight Service in a consultative capacity, when needed.

The AC supplants the General Aviation Pilot’s Guide to Preflight Weather Planning, Weather Self-Briefings, and Weather Decision Making (PDF) published in 2006.

The AC includes checklists to help you collect and use weather reports and forecasts, NOTAMs, and other information required by 14 CFR § 91.103, and the AC updates references to sources such as FSS (via Leidos), ADS-B, and websites that provide supplemental information about special-use airspace, charts, and other data.

The first two background paragraphs of the AC include language that encourages pilots to use FSS as “a consultative resource that can be utilized when needed.”

6.1 Flight Service ( provides service and value to users of the NAS, leveraging advanced technologies to safely and efficiently deliver Flight Services in the continental United States (CONUS), Hawaii, Puerto Rico, and Alaska. Flight Service provides continuous assessment of Flight Services based on feedback and continued research and development of new aviation technology to enhance efficiency and add value for pilots. Flight Service increases aviation safety by making aeronautical information and METI accessible where and when you need it with the evolution of pilot weather briefings conducted using automated resources.

6.2 The FAA encourages innovation in the delivery of services to pilots. User preferences for automation and new distribution methods make communication with pilots easier and faster. Pilots are encouraged to utilize online automated weather resources to conduct self-briefings prior to contacting Flight Service. Pilots who have preflight weather/risk assessment and risk mitigation skills are better prepared to make in-flight decisions as real-time weather information is consumed. This allows Flight Service to become a consultative resource that can be utilized when needed.

In section 7 GENERAL OPERATING PRACTICES, paragraph 7.1 Preflight Actions also notes that:

However, most pilots have become more accustomed to performing a self-briefing than calling an FSS. The FAA considers that a self-briefing may be compliant with current Federal aviation regulations. By self-briefing, pilots can often improve their knowledge of weather and aeronautical information. Flight Service personnel are available should a pilot need assistance.

These statements align with the FAA Plans for FSS Modernization:

The FAA’s Future Flight Services Program (FFSP) vision is to transform and modernize the delivery of flight services over a 15-year period. The FAA believes that costs can be reduced by focusing on changing user behavior and migrating to automated, self-assisted service delivery models, while still maintaining quality of service and safety.

For more background about preflight briefings, see What Qualifies as an Official Preflight Briefing?

Using GPS on Conventional Procedures

I get many questions from pilots about how they can use an IFR-approved GPS while flying departures, airways, arrivals, and approaches that are based on or include navaids—VORs, DME, localizers—and sometimes even NDBs. The current guidance from avionics handbooks, instructors, and FAA publications, such as AC 90-108 and AIM 1-2-3, isn’t always easy to understand, and some details have evolved as new avionics have become available.

The video presentation below takes a close look at the FAA guidance on the topic and uses specific examples to help you understand how you can use a suitable RNAV system–for most GA pilots, that means an IFR-approved GPS–to fly all or parts of departures, airways, arrivals, and approaches that are based on navaids.

For more information on this topic, see the following posts here at BruceAir:

To see more presentations for pilots, check this playlist at my YouTube channel, BruceAirFlying.

Webinar: Briefing IFR Procedures

On February 9, I presented a webinar about Briefing IFR Procedures. The event was hosted by the American Bonanza Society (I’m an instructor for the Beechcraft Pilot Proficiency Program at ABS).

You can watch the recording of the webinar on the ABS website, here (ABS membership is not required).

For more information about how I annotate electronic charts, see Annotating IFR Charts and Stylus for iPad and ForeFlight ScratchPads and Annotations.

The Final Approach “Fix” on an ILS

Consider the ILS RWY 26 at Lewiston, ID (KLWS). This approach is a “pure” ILS; it doesn’t offer an “or LOC” option.

Here’s a question that came up recently during a presentation that I gave to a group of IFR pilots:

“Where’s the final approach fix?”

The profile view does not include the familiar “Maltese cross” that marks the FAF on charts for procedures that include minimums for both a full ILS (a precision approach with a glideslope) and a localizer-only, nonprecision approach to an MDA, as on the ILS RWY 20 at KPWT.

But because the chart for KLWS is only for a precision approach, it doesn’t have a charted “final approach fix.”

AIM 5−4−5. Instrument Approach Procedure (IAP) Charts includes a note that explains the situation:

The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude. This point marks the PFAF [precision final approach fix] and is depicted by the ”lightning bolt” symbol on U.S. Government charts. Intercepting the glide slope at this altitude marks the beginning of the final approach segment and ensures required obstacle clearance during descent from the glide slope intercept altitude to the lowest published decision altitude for the approach.

The Aeronautical Chart User’s Guide also explains:

Non-Precision Approaches
On non-precision approaches, the final segment begins at the Final Approach Fix (FAF) which is identified with the Maltese cross symbol. When no FAF is depicted, the final approach point is the point at which the aircraft is established inbound on the final approach course. Stepdown fixes may also be provided between the FAF and the airport for authorizing a lower minimum descent angle (MDA) and are depicted with the fix or facility name and a dashed line. On non-precision only approach procedures, the approach track descends to the MDA or VDP point, thence horizontally to the missed approach point.

The ACG offers the following additional distinction:

Precision Approaches
On precision approaches, the glideslope (GS) intercept altitude is illustrated by a zigzag line and an altitude. This is the minimum altitude for GS interception after completion of the procedure turn. Precision approach profiles also depict the GS angle of descent, threshold crossing height (TCH) and GS altitude at the outer marker (OM) or designated fix.

The plan and profile views for the KLWS approach may further confuse matters because they include a computer navigation fix (CNF); in this case (CFLSK). The Pilot/Controller Glossary explains CNF thus:

COMPUTER NAVIGATION FIX (CNF)- A Computer Navigation Fix is a point defined by a latitude/longitude coordinate and is required to support Performance-Based Navigation (PBN) operations. A five-letter identifier denoting a CNF can be found next to an “x” on en route charts and on some approach charts. Eventually, all CNFs will be labeled and begin with the letters “CF” followed by three consonants (e.g., ‘CFWBG’). CNFs are not recognized by ATC, are not contained in ATC fix or automation databases, and are not used for ATC purposes. Pilots should not use CNFs for point-to-point navigation (e.g., proceed direct), filing a flight plan, or in aircraft/ATC communications… (REFER to AIM 1-1-17b5(i)(2), Global Positioning System (GPS). [See below for a more detailed explanation.]

Back to AIM 5-4-5. If you’re flying an ILS, make sure you observe any altitude restrictions outside the published GS intercept altitude. The AIM cautions that:

Interception and tracking of the glide slope prior to the published glide slope interception altitude does not necessarily ensure that minimum, maximum, and/or mandatory altitudes published for any preceding fixes will be complied with during the descent. If the pilot chooses to track the glide slope prior to the glide slope interception altitude, they remain responsible for complying with published altitudes for any preceding stepdown fixes encountered during the subsequent descent.

More about CNFs from AIM 1-1-17b5(i)(2):

A Computer Navigation Fix (CNF) is also a point defined by a latitude/longitude coordinateand is required to support Performance−Based Navigation (PBN) operations. The GPS receiver uses CNFs in conjunction with waypoints to navigate from point to point. However, CNFs are not recognized by ATC. ATC does not maintain CNFs in their database and they do not use CNFs for any air traffic control purpose. CNFs may or may not be charted on FAA aeronautical navigation products, are listed in the chart legends, and are for advisory purposes only. Pilots are not to use CNFs for point to point navigation (proceed direct), filing a flight plan, or in aircraft/ATC communications. CNFs that do appear on aeronautical charts allow pilots increased situational awareness by identifying points in the aircraft database route of flight with points on the aeronautical chart. CNFs are random five-letter identifiers, not pronounceable like waypoints and placed in parenthesis. Eventually, all CNFs will begin with the letters “CF” followed by three consonants (for example, CFWBG). This five-letter identifier will be found next to an “x” on enroute charts and possibly on an approach chart. On instrument approach procedures (charts) in the terminal procedures publication, CNFs may represent unnamed DME fixes, beginning and ending points of DME arcs, and sensor (ground-based signal i.e., VOR, NDB, ILS) final approach fixes on GPS overlay approaches. These CNFs provide the GPS with points on the procedure that allow the overlay approach to mirror the ground-based sensor approach. These points should only be used by the GPS system for navigation and should not be used by pilots for any other purpose on the approach. The CNF concept has not been adopted or recognized by the International Civil Aviation Organization (ICAO).

Note that a modern GPS-based navigator like the Garmin GTN 750 includes the CNF fix CFLSK in the flight plan when you load the ILS RWY 26. And it conveniently labels it as the FAF; that fix corresponds to the GS intercept altitude and marks the beginning of the final approach segment.

Garmin PC Trainer Suite Update

Garmin has updated the free the PC Trainer Suite for GTN, G500/G600 TXi, GDU 620, GNX 375, GNC 355/355A, and GPS 175. You can find the new download here.

Note that the date on the web page is January 4, 2020; it should be 2021.

The PC Trainer Suite is a great tool for learning about, teaching, and practicing with Garmin’s latest panel-mount avionics for light GA aircraft. The key display elements and logic for navigating, flying procedures, etc. is essentially the same across the Garmin line, so this trainer can also help you teach about and learn the G1000, G5, and various panel-mount GPS navigators.

The web page shows the updates and system requirements for this version, which includes navigation/procedure/chart databases from May 2020.

New T-Routes in Las Vegas

FAA will establish several new T-routes (and high-altitude Q-routes) in the Las Vegas area on February 25, 2021 (notice in the Federal Register here). The final rule explains:

These Q and T routes facilitate the movement of aircraft to, from, and through the Las Vegas terminal area. Additionally, the routes promote operational efficiencies for users and provide connectivity to RNAV enroute procedures while enhancing capacity for adjacent airports.

Below are some details about the new low-altitude T-routes (T-338, T-357, T-359, T-361, and T-363) from the FAA announcement. The notice, however, does not include the minimum IFR altitudes for the routes (MEAs). To see how these routes connect to IFR departures, arrivals, and approaches, check the new procedure charts when they are published. (The new VFR charts are now available as large PDFs at the FAA website, here. The IFR charts are also available for download.)

For more information about T-Routes, see AIM 5-3-4 Airways and Route Systems.

Below are excerpts from the new sectional, TAC, and IFR low-altitude enroute charts effective 25 February 2021.

T-338 is established between the DSIRE, NV, WP to the BOEGY, AZ, WP. T-338 provides a lateral path for arrivals and departures to the North Las Vegas Airport (KVGT), Boulder City Municipal Airport (KBVU) and KLAS. Additionally, it serves propeller aircraft arriving at KVGT and KLAS from points east or that are departing from KVGT and KLAS to points east.

T-357 is established between the KONNG, NV, WP to the DSIRE, NV, WP. T-357 provides a predictable and repeatable path for overflights through the Las Vegas TRACON airspace and serves as an arrival/departure airway for KVGT, Henderson Executive Airport (KHND), KBVU, and KLAS aircraft.

T-359 is established from the DANBY, CA, WP to the DSIRE, NV, WP. T-359 provides a predictable and repeatable path for overflights through the Las Vegas TRACON airspace and serve as an arrival/departure airway for KVGT, KHND, KBVU, and KLAS aircraft. T-359 reduces the current requirement for air traffic control facilities to issue radar vectors or itinerant routing for KVGT arrivals/departures or overflights.

T-361 is established from the BOEGY, AZ, WP to the Mormon Mesa, NV, VORTAC (MMM). T-361 provides a predictable and repeatable flight path for aircraft flying through the Las Vegas TRACON airspace and to serve as an arrival/departure airway for KLAS, KVGT, KBVU, and KHND. T-361 reduces the current requirement for air traffic control facilities to issue radar vectors or itinerant routing for KLAS and KHND.

T-363 is established from the DICSA, NV, FIX to the Mormon Mesa, NV, VORTAC (MMM). T-363 provides a predictable and repeatable path for propeller-driven arrivals and departures to and from KHND, KBVU, and KLAS to and from points north and northeast.

AIM Updates Navaid Service Volumes

The December 31, 2020 edition of the AIM is out. This edition includes only a few updates, but section 1−1−8 NAVAID Service Volumes, provides a detailed explanation of new navaid standard service volumes (SSV) for VORs and DME, largely to support the change to performance based navigation (PBN).

Paragraph (a) of the section explains that:

The FAA publishes Standard Service Volumes (SSVs) for most NAVAIDs. The SSV is a three−dimensional volume within which the FAA ensures that a signal can be received with adequate signal strength and course quality, and is free from interference from other NAVAIDs on similar frequencies (e.g., co−channel or adjacent−channel interference). However, the SSV signal protection does not include potential blockage from terrain or obstructions. The SSV is principally intended for off−route navigation, such as proceeding direct to or from a VOR when not on a published instrument procedure or route. Navigation on published instrument procedures (e.g., approaches or departures) or routes (e.g., Victor routes) may use NAVAIDs outside of the SSV, when Extended Service Volume (ESV) is approved, since adequate signal strength, course quality, and freedom from interference are verified by the FAA prior to the publishing of the instrument procedure or route.

Details follow in paragraph (2):

With the progression of navigation capabilities to Performance Based Navigation (PBN), additional capabilities for off−route navigation are necessary. For example, the VOR MON (See paragraph 1−1−3 f.) requires the use of VORs at 5,000 feet AGL, which is beyond the original SSV ranges. Additionally, PBN procedures using DME require extended ranges. As a result, the FAA created four additional SSVs. Two of the new SSVs are associated with VORs: VOR Low (VL) and VOR High (VH), as shown in FIG 1−1−4. The other two new SSVs are associated with DME: DME Low (DL) and DME High (DH), as shown in FIG 1−1−5. The SSV at altitudes below 1,000 feet for the VL and VH are the same as FIG 1−1−3. The SSVs at altitudes below 12,900 feet for the DL and DH SSVs correspond to a conservative estimate of the DME radio line of sight (RLOS) coverage at each altitude (not including possible terrain blockage).

TBL 1−1−1, SSV Designator Altitude and Range Boundaries, and a couple of figures provide the details. ATH=Above Transmitter Height.

SSV DesignatorAltitude and Range Boundaries
T (Terminal)From 1,000 feet ATH up to and including 12,000 feet ATH at radial distances out to 25 NM.
L (Low Altitude)From 1,000 feet ATH up to and including 18,000 feet ATH at radial distances out to 40 NM.
H (High Altitude)From 1,000 feet ATH up to and including 14,500 feet ATH at radial distances out to 40 NM. From 14,500 ATH up to and including 60,000 feet at radial distances out to 100 NM. From 18,000 feet ATH up to and including 45,000 feet ATH at radial distances out to 130 NM.
VL (VOR Low)From 1,000 feet ATH up to but not including 5,000 feet ATH at radial distances out to 40 NM. From 5,000 feet ATH up to but not including 18,000 feet ATH at radial distances out to 70 NM.
VH (VOR High)From 1,000 feet ATH up to but not including 5,000 feet ATH at radial distances out to 40 NM. From 5,000 feet ATH up to but not including 14,500 feet ATH at radial distances out to 70 NM. From 14,500 ATH up to and including 60,000 feet at radial distances out to 100 NM. From 18,000 feet ATH up to and including 45,000 feet ATH at radial distances out to 130 NM.
DL (DME Low)For altitudes up to 12,900 feet ATH at a radial distance corresponding to the LOS to the NAVAID. From 12,900 feet ATH up to but not including 18,000 feet ATH at radial distances out to 130 NM
DH (DME High)For altitudes up to 12,900 feet ATH at a radial distance corresponding to the LOS to the NAVAID. From 12,900 ATH up to and including 60,000 feet at radial distances out to 100 NM. From 12,900 feet ATH up to and including 45,000 feet ATH at radial distances out to 130 NM.

Standard-Rate Turns

Here’s my latest Tip of the Week for Pilot Workshops:

Standard-Rate Turn Secret.

Theories of Lift

I just completed giving two end-of-course checks to flight instructor applicants during which the candidates explained lift, at least in part, by presenting the so-called equal transit time theory. That is, when a pair of air molecules encounters the leading edge of an airfoil, the molecule flowing over the curved top of the wing must travel a longer distance than its companion moving beneath the wing. The molecule on top must therefore move faster to meet its companion at the trailing edge. Pressure drops as a fluid’s speed increases, Bernoulli’s principle, and so forth.

Unfortunately, the equal transit time explanation is wrong, and has long been recognized as an error (see, e.g., Babinsky’s Demonstration: The Theory of Flight and Its Historical Background [PDF]). There’s no physical process that would require the two molecules to meet (we’re not talking quantum entanglement here). In fact, numerous wind tunnel studies and other demonstrations confirm that, while the air flowing over the top of the wing does indeed speed up, and its pressure does in fact drop, particles that start together at the leading edge don’t meet. A molecule taking the (typically slightly) longer upper path in fact ends up far ahead of its cohort that follows the shorter path below. The video below shows the physical reality.

This longer video provides additional details. This one’s good, too.

Indeed, as Doug MacLean (see below) explains, the typical difference in the length of the pathways above and below an airfoil is about an order of magnitude too small to produce the actual observed lift. Moreover, symmetrical airfoils, and even flat planes, provided they meet a stream at an angle of attack, produce lift (more or less efficiently, to be sure) despite the fact that the distances the molecules must travel are effectively equal.

Clearly something (or somethings) else is (are) going on.

Doug MacLean, a retired Boeing aerodynamicist, quotes a former colleague, Philipe Spalart, who said: “It’s easy to explain how a rocket works, but explaining how a wing works takes a rocket scientist.”

(See MacLean in this YouTube video. Warning: There’s math late in the presentation. Triple integrals…)

Here’s a recent, accessible article from Scientific American about various theories of how airfoils create lift. It’s a good read that explains several key points. A teaser:

…Adding to the confusion is the fact that accounts of lift exist on two separate levels of abstraction: the technical and the nontechnical. They are complementary rather than contradictory, but they differ in their aims. One exists as a strictly mathematical theory, a realm in which the analysis medium consists of equations, symbols, computer simulations and numbers. There is little, if any, serious disagreement as to what the appropriate equations or their solutions are. The objective of technical mathematical theory is to make accurate predictions and to project results that are useful to aeronautical engineers engaged in the complex business of designing aircraft.

But by themselves, equations are not explanations, and neither are their solutions. There is a second, nontechnical level of analysis that is intended to provide us with a physical, commonsense explanation of lift. The objective of the nontechnical approach is to give us an intuitive understanding of the actual forces and factors that are at work in holding an airplane aloft. This approach exists not on the level of numbers and equations but rather on the level of concepts and principles that are familiar and intelligible to nonspecialists.

It is on this second, nontechnical level where the controversies lie. Two different theories are commonly proposed to explain lift, and advocates on both sides argue their viewpoints in articles, in books and online. The problem is that each of these two nontechnical theories is correct in itself. But neither produces a complete explanation of lift, one that provides a full accounting of all the basic forces, factors and physical conditions governing aerodynamic lift, with no issues left dangling, unexplained or unknown. Does such a theory even exist?

Read the article for a more complete discussion. You can also find excellent visualizations and explanations via the Lippisch videos, discussed in The Secret of Flight–Dr. Alexander Lippisch.

In the meantime, it seems the best we can do as flight instructors is explain that airfoils are shapes that efficiently produce lift as they move through the air (or the air moves over them). Pressure does in fact drop above an airfoil at a positive AoA resulting in an upward force. The air around an airfoil also is deflected and therefore accelerated (it has a change in velocity, by definition an acceleration), and, as MacLean argues, Newton’s Second Law (F=ma), not so much the Third Law (equal and opposite forces) applies. Lift and drag are the results, and we as pilots can control lift and drag by using the elevator control to change AoA, extending flaps, etc.

But the smart people who try to understand what causes these phenomena still can’t agree on complete theory of lift. As the Scientific American article concludes:

“One apparent problem is that there is no explanation that will be universally accepted,” [Drela] says. So where does that leave us? In effect, right where we started: with John D. Anderson, who stated, “There is no simple one-liner answer to this.”

Redefining Designated Mountainous Areas

FAA is working on a long-term project to redefine Designated Mountainous Areas, a change that could allow lower IFR altitudes in many parts of the western U.S. and in sections of higher terrain in the East. The project was a topic at the October 2020 session of the Aeronautical Charting Meeting; the images below come from an FAA presentation at that meeting.

First, some background. The current Designated Mountainous Areas (DMA) are described in 14 CFR Part 95 Subpart B (originally published in 1963). The references that apply to the continental U.S. are:

  • §95.13   Eastern United States Mountainous Area.
  • §95.15   Western United States Mountainous Area.

Figure 5-6-3 from the AIM shows these areas highlighted in blue. In general, the western third of the U.S., with a couple of exceptions in the Central Valley of California and part of the Puget Sound region near Seattle, is designated as a mountainous area. Another swath covers the high terrain from Alabama to New England, with exceptions in New York and Maine.

In a DMA, the minimum altitudes for IFR flight (explicitly defined in 14 CFR §91.177) must be 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown. Because the current DMA, especially in the West, covers such a large area, the MEAs for airways and minimum IFR altitudes that ATC must use can be unnecessarily high in regions such as central Washington and Oregon and similar wide valleys and basins in other states. This issue has become more important as we evolve to GPS navigation that supports direct RNAV routes and as ATC applies ADSB to its surveillance capabilities.

The FAA project seeks to redefine mountainous areas more specifically as:

Designated mountainous areas include those areas having a terrain elevation differential exceeding 3,000 feet within 10 nautical miles within those one arc-second quadrangles overlying terrain or U.S. territorial waters.

This new definition would also align with that used by ICAO.

Illustrations from the presentation at the ACM meeting help clarify the proposed change. These images (not to scale) show how the terrain in each quadrangle is evaluated.

For example, here’s a depiction of how the DMA in the West would change under the new rule. The shaded blue area shows the current DMA. The new definition would require the designation only for the orange-brown areas.

The DMA in the East would also shrink.

The practical effects of the change would alter the requirements for different phases of IFR flight. For example, pilots of piston-powered aircraft could have more flexibility in choosing IFR routes at comfortable altitudes, whether flying airways or RNAV direct. The new DMA could also provide more options when avoiding icing and allow new IFR departure procedures.

For example, when planning an off-airways route under IFR, you must consider the OROCA (although an OROCA is not, in itself, a legal minimum IFR altitude; see 14 CFR §91.177). The AIM defines OROCA thus:

OROCA is an off−route altitude which provides obstruction clearance with a 1,000 foot buffer in non-mountainous terrain areas and a 2,000 foot buffer in designated mountainous areas within the U.S. This altitude may not provide signal coverage from ground−based navigational aids, air traffic control radar, or communications coverage.

ATC must also apply minimum IFR altitudes when clearing you direct off-airways and other published route segments. As the AIM explains:

The minimum vectoring altitude [or minimum IFR altitude (MIA)] in each sector provides 1,000 feet above the highest obstacle in non-mountainous areas and 2,000 feet above the highest obstacle in designated mountainous areas. Where lower MVAs are required in designated mountainous areas to achieve compatibility with terminal routes or to permit vectoring to an IAP, 1,000 feet of obstacle clearance may be authorized with the use of Airport Surveillance Radar (ASR). The minimum vectoring altitude will provide at least 300 feet above the floor of controlled airspace.

Departure procedures are also constrained by DMA. When FAA develops ODPs and SIDs, the AIM explains, planners must evaluate obstacles around an airport:

The 40:1 obstacle identification surface (OIS) begins at the departure end of runway (DER) and slopes upward at 152 FPNM until reaching the minimum IFR altitude or entering the en route structure. This assessment area is limited to 25 NM from the airport in non-mountainous areas and 46 NM in designated mountainous areas.

The expanded OIS required in current DMA can result in steep climb gradients, course changes, and other requirements that can make IFR departures challenging, even when an airport is located in a broad valley or basin.

The effort to redefine DMA is a long project. The timeline below shows that work began in 2017.

A draft NPRM is scheduled for publication in February 2021, but the date may slip due to COVID. And at present, there’s no date for implementation. Changing the DMA would require extensive coordination and updates to legally defined routes, all types of IFR charts, databases, ATC resources and procedures, and FAA publications, including IFR training handbooks. Nevertheless, the effort is a welcome sign of progress as we adopt new navigation technologies and avionics.