Flying an Approach with only an iPad

You’re suddenly having a bad IFR day. As you approach your destination, Huron, SD, after a routine departure and a comfortable cruise in IMC, most of your panel abruptly goes dark. You still have basic flight instruments, including an electronic PFD and an HSI, which run on backup batteries. Your last communications with ATC included a clearance to an initial approach fix and “expect the ILS RWY 12 approach.” But your GPS navigator, which includes navigation receivers, is now kaput, along with your second nav/com. In other words, you have no moving map or course guidance in the panel–just attitude, airspeed, altitude, and heading. You can’t even see a GPS track indicator.

The good news is, you have an iPad with a built-in GPS (or a tablet connected to an external GPS source) running ForeFlight or a similar app. The EFB confirms that your blue “own ship” symbol is tracking toward HUMSO, an initial approach fix that marks the beginning of a feeder route that takes you to the final approach course.

Using just your track shown on the approach chart, and your basic instrument flying skills, can you fly the approach?

I practice such scenarios periodically during recurrent training. In my A36 Bonanza, operating under VFR with a safety pilot, I switch the navigation screen on my GTN 750Xi to the traffic page, which provides no navigation information, and then I practice getting to an airport and flying an approach using only the iPad for guidance.

Of course, an iPad isn’t a “suitable RNAV system” as defined in the AIM and FAA advisory circulars, but in IMC under IFR, this scenario qualifies as an emergency, and you can bend the rules as necessary to arrive safely.

As you’ll see in this video, a challenge like this is also an excellent workout in an aviation training device. Galvin Flying, the flight school in Seattle where I instruct, has two ATDs made by one-G Simulations. They emulate C172s. You can connect ForeFlight to the Wi-Fi signals broadcast by each trainer, which send position, altitude, speed, and other information to your tablet. As far as ForeFlight is concerned, you’re flying.

Just as in the airplane, provided your EFB can receive GPS signals, you have a good 2-D navigation solution. If you can keep your blue airplane tracking along the lines on a geo-referenced approach chart, you’ll follow the intended path. What you don’t get, however, is any type of vertical guidance. It’s up to you to establish and maintain a steady descent that keeps you as close as possible to an ILS glideslope or a GPS glidepath for an approach to a DA, or to the profile for a non-precision approach to an MDA.

You may also want to practice using the synthetic vision feature, if your EFB app supports it. Although I prefer flying with the procedure chart visible, synthetic vision would be a terrific aid if you lose the basic flight instruments.

Flying an approach like this successfully requires mastery of fundamental instrument skills, what we used to call flying with only “needle, ball, and airspeed.” You must understand and be able to apply the control-performance method of instrument flying—establishing the appropriate attitude, setting power and configuration, monitoring your progress, and making constant, smooth adjustments as you proceed. In other words, it’s a good test that takes you back to drills like flying Pattern A and Pattern B that you practiced early in your IFR training.

Watch the video to see how accurately I flew two approaches in the ATD with just the airplane symbol on an approach chart for guidance.

A Practice Approach to a Long Runway

I recently flew the A36 Bonanza to Grant County Airport (KMWH) at Moses Lake in central Washington state. This short video shows a practice ILS in visual conditions to runway 32R, which at 13,500 ft (4,116 m) is one of the longest runways in the U.S. In fact, this runway at the former Larson Air Force Base was an alternate landing site for the Space Shuttle.

A Scenic Approach to Boeing Field

I recently flew the A36 Bonanza from Boeing Field (KBFI) in Seattle to Grant County Airport (KMWH) at Moses Lake, WA and back, taking advantage of a break in the weather to cross the Cascade Mountains again before winter weather makes such trips increasingly rare.

The return to KBFI included a visual approach that passed over Seattle-Tacoma International Airport (KSEA) to a swooping descent over Puget Sound and through Elliott Bay to runway 14R.

I also captured videos of the flight to and from KMWH, which you can watch on my YouTube channel here and here.

Mixing RNAV and an ILS

If you fly an airplane with a suitable RNAV system (for most of us, that’s an IFR-approved GPS navigator in the panel), you’re accustomed to flying RNAV (GPS) approaches and other procedures, such as RNAV departures and arrivals. And since most RNAV navigators currently in use also support flying ILS and VOR procedures, you also probably still fly the occasional ILS or VOR approach, even if you prefer all-GPS procedures.

But as the shift to Performance-Based Navigation (PBN) continues, the FAA is publishing more approaches that include–and sometimes require–using both GPS-based RNAV systems and ground-based navaids.

For other examples, see An ILS that Requires GPS, and the ILS OR LOC RWY 21 at KSTE in WI.

Consider the ILS or LOC RWY 12 at Huron (KHON), a small town in South Dakota.

In many respects, this is a typical ILS. It offers a DA at 200 AGL and requires 1/2 sm visibility (the RNAV (GPS) approach to RWY 12 offers the same LPV minimums). It also has an old-school locator outer marker (LOM) at BEADY that serves as the final approach fix for the LOC-only version of the approach and as the anchor for the missed-approach holding pattern.

But read the note in the required equipment box.

In most light aircraft these days, you must also have an IFR-approved GPS to fly the feeder routes and to identify BEADY, because your panel probably doesn’t include DME or an ADF.

ATC could provide vectors to steer you from the enroute environment to the final approach course. But as I’ve noted elsewhere, if you filed IFR as an RNAV/PBN-capable aircraft, a controller can clear you direct to any initial approach or intermediate fix, even if you’re flying a conventional procedure like an ILS.

The enroute chart for the area around Huron shows why you might expect such a clearance. The closest VOR at Watertown (ATY) is nearly 40 nm away, and the airways that converge at KHON are all GPS-based T-routes. The VOR at HON has been decommissioned; only the DME component remains (for more information, see Stand-Alone DMEs on Charts).

A controller can avoid issuing a series of vectors and altitudes as you fly toward the airport and offer one simple instruction, “Cross HUMSO [or WEDEM] at or above 3000, cleared for the ILS RWY 12 approach.”

Your task is to brief the plan for changing from GPS guidance to fly the feeder route from either HUMSO or WEDEM to “green needles” to intercept and track the localizer as you turn inbound toward the airport. And decide, if necessary, how you’ll fly the missed approach.

So today, even if you’re flying to a GA airport far from the big city, you should be prepared to load and fly such hybrid procedures if, for training or practice, you want to fly an ILS, LOC, or VOR approach.

Special Military Activity Routes

Here’s an airspace puzzle for SUA aficionados: What’s a SMAR (or Special Military Activity Route), as shown on this part of a sectional chart in Nevada, near the Wilson Creek VOR (ILC)?

SMAR look similar to other SUA (e.g., MOAs) on VFR charts. The areas they enclose are outlined with blue hash marks, and they have top and bottom altitudes. Unlike MOAs, restricted areas, and controlled firing areas, however, SMAR don’t have names or numerical designations.

A note on a sectional chart that includes a SMAR explains their purpose.

The chart identifies IFR Military Training Routes and Military Operations Area within which the Department of Defense conducts periodic operations involving Unmanned Aircraft Systems. These aircraft may be accompanied by military or other aircraft which provide the pilots of the Unmanned Aircraft Systems visual observation information about other aircraft operations near them.

In other words, they’re…special, as I learned while attending (virtually) the October 2022 session of the Aeronautical Charting Meeting hosted by the FAA.

A recommendation document submitted by a pilot for discussion (PDF) explained his confusion when he encountered a SMAR on a flight. As he explained to the group, he contacted Flight Service for information, but the specialist couldn’t help, because the pilot couldn’t provide a name for, or other details about, the airspace.

SMARS are noted on the border (but not the legend) of a sectional chart (see below).

And p. 31 of Aeronautical Chart User’s Guide also notes how SMAR are depicted:

But SMAR aren’t described in AIM Section 4. Special Use Airspace, and as the discussion at the meeting revealed, most pilots don’t understand how to get information about the status of a SMAR.

Experts at the ACM did reveal one important detail that’s essential when you want to check the status of a SMAR. These areas are associated with IFR Military Training Routes.

IFR MILITARY TRAINING ROUTES (IR)− Routes used by the Department of Defense and associated Reserve and Air Guard units for the purpose of conducting low-altitude navigation and tactical
training in both IFR and VFR weather conditions below 10,000 feet MSL at airspeeds in excess of 250 knots IAS.

P/C Glossary

In the example here, the SMAR outlines the lateral and vertical boundaries of IR200 when it’s being used for SMAR-related activities. So if you want to find out whether a SMAR is in use, check NOTAMS (active IR routes should be included in your preflight briefing) and use the IR number when you contact ATC or FSS.

Video: Tips for IFR Flights

Fall weather finally arrived in Seattle, so I took advantage of IFR-and MVFR conditions to fly the Bonanza on a short hop from Boeing Field (KBFI) to Arlington (KAWO).

A glitch meant that I didn’t capture ATC or intercom audio on this flight, so instead this video describes some of the techniques and procedures that I use on a typical IFR flight. And I explain how I dealt with an unexpected curve during the approach at Arlington.

A flight from Boeing Field to Arlington in the Bonanza typically involves only about 20 minutes in the air. Under IFR, it’s important to manage the workload—updating the preflight briefing with the latest information, obtaining an IFR clearance, setting up the airplane and avionics, flying a departure procedure, and being ready to begin an approach as soon as you level off.

For example, before I even start the engine, I call the phone numbers for the ATIS or AWOS at my departure and destination and fill in the ForeFlight scratchpads. That way, I have the basic information and I can quickly confirm the current ATIS letter and update the one-minute weather when I contact ATC before takeoff and as I begin the approach that I want to fly, based on the wind and other details.

See the video for other tips, such as annotating charts and loading–but not activating–approaches.

VOR Service Volumes on IFR Charts

The September 8, 2022 edition of the Aeronautical Chart User’s Guide notes that:

Beginning with the September 8, 2022, publication date, all Standard Service Volume designations will be shown for VOR, VOR/DME, VORTAC, DME, and TACAN NAVAIDs on both the IFR Enroute Low and High Attitude charts.

Publishing this information is part of the FAA plan to implement the Minimum Operational Network (MON) of VORs (see also AIM 1-1-3-f), which will leave some 589 VORs still in operation after the program is complete, now scheduled in FY2030.

As the FAA decommissions VORs, mostly in the East and Midwest, it is expanding the service volumes of the navaids to help ensure signal coverage for aircraft not equipped with GPS or during GPS outages. The table below, from the Aeronautical Chart User’s Guide, shows both the new service volumes and the codes used on IFR charts to identify the service volume associated with each VOR.

Here’s a section of a low-altitude IFR chart that shows navaid information boxes with some of the new standard service volume classifications.

You can find more information about the new VOR service volumes in AIM 1−1−8. NAVAID Service Volumes.

Slowing Down in Time

I recently wrote a Tip of the Week for Pilot Workshops called The Right Time to Slow Down. That tip describes a technique I that I teach to help pilots learn how long it takes their aircraft to decelerate from normal cruise to a good speed for initial approach when IFR or to enter the traffic pattern when VFR.

The basic idea is simple:

  • Set up your airplane at its normal cruise power and configuration.
  • If you have an autopilot, set it to hold altitude and heading (or to track to a fix directly ahead).
  • Start a timer.
  • Reduce power to your normal initial approach or pattern MP and RPM.
  • Note how long it takes for the airplane to stabilize at your target initial approach/pattern speed.

In an airplane like a Cessna 172, start the exercise at a typical cruise setting of 2300-2400 RPM. The airspeed should be 100-105 KIAS. Smoothly reduce power to 2000-2100, and in about 30 seconds, (as shown in the video below, captured in Microsoft Flight Simulator) the airplane will slow to about 90 KIAS, a good speed for initial approach or the traffic pattern. You’re stable, below the speed where you can extend the first 10 degrees of flaps and manage other tasks.

When I instruct in Beechcraft Bonanzas, I talk about the “happy place,” a stable configuration for initial approach and the VFR pattern. In a typical Bonanza, set the power at 17-18 in MP and 2300-2500 RPM, clean, for a speed of 125-130 KIAS. Slowing from normal cruise at about 23 in MP and 2300-2500 RPM to the “happy place” takes about 90 seconds, as you can see in the video below, also captured in Microsoft Flight Simulator.

Practicing this drill is a great exercise in an aviation training device (ATD) and in your airplane. You can experiment with several variations of speed, power settings, and flap settings (see also another Tip of the Week: Learning the Numbers) to help you quickly and consistently set up your airplane for common situations, reducing your workload and giving you more time for important tasks such as looking out for traffic, completing flows and checklists, briefing approaches, and following instructions from ATC.

I Survived a Downwind Turn

One of the most persistent misconceptions in aviation is that so-called downwind turns are dangerous. Proponents of this fallacy typically present the following basic argument:

Consider an airplane flying due north at, say, 100 KIAS into a 30 knot direct headwind. The airplane’s groundspeed is therefore 70 knots. If the airplane, still flying at an indicated airspeed of 100 knots, turns 180 degrees to a heading of due south, it needs to “gain” 60 knots to match its new groundspeed of 130 knots—that is, the sum of its airspeed and the wind velocity. A pilot who doesn’t take care to add power or push the nose down to help the airplane “gain energy” in the turn risks stalling and falling out the sky.

That argument may seem logical and consistent, but it doesn’t hold up when we actually do the experiment, as you can see in the video below.

I took advantage of an IFR training flight with a student in a C172 to capture the “downwind turn” phenomenon in action. We had flown an instrument approach and then climbed to 4000 ft to enter and fly the published hold at CARRO intersection, a fix located 24 nm southwest of the SEA VOR.

The track data shows that as we flew the outbound leg of the hold, we were cruising at about 100 KIAS almost directly into a wind of about 30 knots.

When we turned 180 degrees back inbound to CARRO, our airspeed remained essentially constant (the student was hand-flying the aircraft, which doesn’t have an autopilot).

Our groundspeed varied from about 80 knots outbound to some 120 knots on the inbound leg. But the pilot didn’t have to add power—or do anything else out of the ordinary—to keep the airplane flying. He just turned as if we were flying on a dead calm day. Because from the airplane’s perspective in the air, the 30-knot wind aloft didn’t exist.

And without looking outside at the ground or checking the groundspeed and wind displays on the PFD, we wouldn’t have sensed the wind, either.

We gained groundspeed thanks to the push from the wind.

As many experts have tried patiently to point out, the key to this situation is knowing that velocity and energy are measured with respect to specific frames of reference.

For example, the kinetic energy of an airplane that concerns us during takeoff, landing, and cruising to our destination—or when crashing into terrain—is a function of groundspeed, which is measured with respect to the earth.

If you are flying at, say, 60 KIAS in zero wind, when your wheels touch the runway you have the kinetic energy associated with 60 knots groundspeed and the aircraft’s mass.

Touch down at, say 60 KIAS into a 20 knot headwind, however, and you have the kinetic energy associated with a velocity of 40 knots, with respect to the earth.

But in both of those situations, your speed through the air remains 60 knots.

As the following excerpt from a column in AOPA Pilot by Catherine Cavagnaro succinctly explains, changes in the aircraft’s kinetic energy with respect to the ground are powered by the wind, and the change in groundspeed applies regardless of the aircraft’s mass or power, because the aircraft is always moving within and along with the air mass in which it is flying, just like a leaf, or a branch, or a boat floating downstream in a river.

A baseball that hits a wall gains no energy in the process. But when it hits a fast-swinging bat, it gains a significant amount before it soars toward the outfield. In the flight scenario, the airplane plays the role of the ball and the wind is the swinging bat. Without wind there is no change in energy from the departure leg to the downwind leg. But the 20-knot wind supplies the extra energy that increases the groundspeed of the airplane. It’s the same energy increase we enjoy as we travel cross-country with a strong tailwind. To avoid a stall in any turn, take the same precautions one does in an ordinary no-wind situation. (Proficiency: Relax and Go With The Flow, AOPA Pilot, August 1, 2019, by Catherine Cavagnaro)

In the air, your energy with respect to the airmass remains the same, regardless of which direction you fly and the presence of wind, if any. You can maneuver at will, and at a given airspeed, the airplane’s kinetic energy with respect to the airmass, regardless of the wind direction, doesn’t change. And when considering stall speeds, your airspeed (actually, angle of attack) measured with respect to the airmass is all that matters—because that velocity is what the wing experiences.

Of course, wind shear—an abrupt change in wind direction and/or speed—and vertical gusts–does affect an airplane. Those phenomena cause variations in angle of attack and G loads. But the myth of the downwind turn isn’t about wind shear. It’s an error caused by conflating frames of reference.

For more information about this topic, see the following articles and other videos:

And for a wonderful presentation about frames of reference and the fundamental principle of relatively (not limited to Einstein), see: Relativity Crash Course by Ramamurti Shankar, a professor of physics at Yale University.