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 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.

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.

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.

Yoke Mount for iPad Mini

When I fly the A36 Bonanza, I mount my iPad Mini on the yoke using a RAM X-Grip with the large strap hose clamp and ball and a short RAM arm to connect the clamp to the X-Grip.

This arrangement works with 1984 and later Beechcraft Bonanzas and Barons, which use conventional yokes, not the big crossbar or throw-over yokes installed in earlier models. The tube that connects the Beechcraft yokes to the mechanisms behind the panel has a larger diameter than the tube used in other aircraft, such as Cessnas, so the large strap hose clamp is necessary to secure the mount.

The X-Grip holds an iPad securely while allowing air to circulate around the tablet, reducing the likelihood that it will overheat in flight. The X-Grip works even when an iPad is in a low-profile case. But it might not hold a tablet that is in a heavier, bulkier case.

How is an LPV Glidepath Created?

Most of us understand how paired LOC and GS signals provide a course and a glideslope to follow when flying an ILS to a decision altitude (DA). (If you’d like a detailed review, see, for example, How ILS Works on the FlightInsight YouTube channel).

But the glidepath you see when flying an RNAV (GPS) approach to LPV minimums (usually shown as a magenta diamond on the vertical deviation scale) is more mysterious.

As this excellent explanation from Honeywell explains:

To make an LPV mimic an ILS’s behavior, LPV relies on programmed coordinates and instructions contained in a Final Approach Segment (FAS) data block. The FAS data block contains instructions for the approach, including coordinates for the runway, threshold crossing height, elevation, glidepath angle, and horizontal and vertical alert limits. The GPS receiver computes both linear and angular deviation but, as previously mentioned, only angular is displayed. They can be thought of as instructions to provide a pseudo localizer and glideslope. 

In other words, the IFR-approved navigation receiver in your panel receives GPS-WAAS signals from space, and then creates a glidepath. The GP that you see and your AP/FD follows doesn’t emanate from a transmitter on the ground. That’s one reason we have so many RNAV (GPS) approaches with LPV minimums, even at small, quiet airports. Except for runway lights and (optional) approach lights, an approach with LPV minimums that mimics an ILS does not require expensive transmitters on the ground.

You GPS-WAAS receiver uses the same principles to create the advisory glidepaths (e.g., LNAV+V and LP+V) that you can use to help you descend to the MDA when flying a 2D (non-precision) approach, or to fly the vertical guidance on the visual approaches available with the latest GPS navigators.

VNAV with a GFC 600 Autopilot

I recently flew the Beechcraft A36 Bonanza from Boeing Field (KBFI) to Aurora State (KUAO) just south of Portland for system software updates at Pacific Coast Avionics.

The IFR flight was in benign weather, but I did need to fly the RNAV (GPS) RWY 35 approach at KUAO. It was a good opportunity to exercise the VNAV capability of the Garmin GFC 600 autopilot. Enjoy the scenery en route and observe the autopilot in action as I explain and use the VNAV feature.

For more information about using VNAV, see Using VNAV During an Instrument Approach.

The departure was pretty, including a nice view of KSEA, but if you want to focus on the approach, start at about 22:10.

And here’s video of the trip back to KBFI via the LOC RWY 32L approach.

“Long IFR XC”: FAA Changes Guidance

FAA recently updated its guidance for instructors and DPEs about the types of approaches that must be accomplished during the so-called long IFR cross-country described in 14 CFR Part 61.65(d)(2)(ii)(C).

That rule requires:

Instrument flight training on cross country flight procedures, including one cross country flight in an airplane with an authorized instructor, that is performed under instrument flight rules, when a flight plan has been filed with an air traffic control facility, and that involves –

(A) A flight of 250 nautical miles along airways or by directed routing from an air traffic control facility;

(B) An instrument approach at each airport; and

(C) Three different kinds of approaches with the use of navigation systems.

Paragraph (C) has caused confusion. For example, some DPEs have said that flying an ILS and then a LOC approach on that “long IFR xc” doesn’t meet the requirement for three different approaches, because both of those procedures are based on a localizer.

The new guidance, described in NOTC2305 (excerpt below) and in a more formal legal memorandum (PDF) dated February 28,2022, distinguishes between types of approaches and types of navigation systems. The notice explains that “the requirements for an instrument rating may be met by performing three different approaches, regardless of the source of navigation.”

The Federal Aviation Administration (FAA) recently reviewed two legal interpretation and determined they were overly restrictive. The Glaser (2008) and Pratte (2012) legal interpretations focused on the requirements of an instrument rating under § 61.65.  Specifically, the requirement to use three different kinds of approaches with the use of navigation systems to meet the requirements of § 61.65(d)(2)(ii)(C).  These interpretations inaccurately concluded that an applicant for an instrument rating must use three different kinds of navigation systems to meet these requirements.

On February 28, 2022, the FAA rescinded both the Glaser and Pratte legal interpretations, stating the regulation’s plain language requires three different types of approaches, not three different navigation systems.  Certificated flight instructors (CFI) and designated pilot examiners (DPEs) should be aware that the requirements for an instrument rating may be met by performing three different approaches, regardless of the source of navigation.  

It’s important to understand, however, that this policy change affects only the specific regulation cited above. That rule describes one of the requirements that an IFR applicant must meet during training, specifically while completing the “long IFR xc,” a flight of at least 250 nm with approaches flown at three different airports.

The new guidance does not change types of approaches flown during a practical test. The requirements for flying precision and non-precision approaches are in the ACS for the instrument rating, and are based in part on the equipment installed in the aircraft used for the practical test.

To clarify the requirements for the long IFR cross-country and the instrument rating practical test, I suggest that FAA publish guidance like the following:

During the cross-country flight required by § 61.65(d)(2)(ii)(C), you must fly three approaches at three airports along the route. The approaches must include:

  • One approach to a DA flown with approved vertical guidance (i.e., an ILS glideslope or a glidepath provided on an RNAV (GPS) approach with LPV or LNAV/VNAV minimums).
  • Two approaches with lateral guidance to an MDA, such as LOC-only, LOC BC, VOR, or RNAV (GPS) procedures. If you are flying an aircraft with avionics capable of displaying advisory vertical guidance while flying non-precision approaches, typically annunciated as +V (e.g., LNAV+V, LP+V, or VOR LNAV+V), you may display and use the advisory vertical guidance as allowed in the AFM and supplements for the avionics installed in the aircraft.
  • A PAR approach may be substituted for an ILS or RNAV (GPS) approach with approved vertical guidance, and an ASR approach may be substituted for one of the non-precision approaches.

We need to be careful, however, about using the terms precision approach and non-precision approach.

As I noted in a blog post about the forthcoming AC 90-119, FAA plans to adopt the new(ish) ICAO definitions for procedures that include 2D (lateral navigation) and 3D (lateral and vertical navigation).

In the past, precision approach applied only to procedures based on ground facilities that provide a glideslope or other approved vertical guidance to a DA–viz., an ILS or PAR. That obsolete definition required the creation of a new term, APV (approaches with vertical guidance), for RNAV procedures that offer approved vertical guidance to LPV or LNAV/VNAV decision altitude minimums.

Today, ICAO has updated its definition of precision approach by describing procedures that include approved vertical guidance to a DA, so-called 3D navigation. ICAO also describes so-called 2D approaches to MDAs.

A Low IFR Approach at KOLM

After a long stretch of widespread fog and icy clouds, the skies in the Puget Sound area cleared—mostly—creating a good opportunity to fly an instrument approach in LIFR conditions at Olympia, the state capital southwest of Seattle.

Ride along in this video at my YouTube channel as I make the short hop in the A36 Bonanza from Boeing Field to fly the RNAV (GPS) RWY 17 approach at KOLM.

The approach offers LPV minimums to the same 200 ft DA and ½ mile visibility as the ILS, and I broke out only a couple of hundred feet above the decision altitude.

The sophisticated avionics and Garmin GFC 600 autopilot in the Bonanza make it easy to fly such approaches. But the skies were busy with training flights, and ATC had its hands full. As you’ll see, one confusing instruction from Seattle Approach had me scratching my head until the controller and I got on the same page.