Interpreting a Instrument Flight Rules (IFR) Approach Chart: A Guide

Interpreting a Instrument Flight Rules (IFR) Approach Chart: A Guide

Decoding the Instrument Flight Rules (IFR) Mess: Unraveling Approach Charts

Tackling an IFR approach chart can feel like entering a labyrinth, but don't fret, we've got your back. Squinting at an approach chart crowded with information may seem overwhelming, but these charts are your lifeline when visual cues vanish. Approach charts, or approach plates, are like navigational compasses, arming you with the necessary details to guide you through a complex approach when things are hazy.

So, grab your coffee, strap on your thinking hat, and let's dive into the nuts and bolts of deciphering an IFR approach chart.

What's this IFR Approach Chart All About?

An IFR approach chart is specifically designed to provide the details you need to execute a particular IFR approach. These charts, officially called Instrument Approach Procedure (IAP) charts, are often referred to as approach plates among pilots.

During an IFR approach, you need to keep track of several bits and bobs, such as the route, descent profile, missed approach procedure, communication frequencies, approach minima, airport details, and more. It's no small feat to cram all that onto a single page, but the result is a treasure trove of essential information.

Feeling bewildered? Let's sift through the four main sections of an approach plate and get acquainted with each section.

Sections of the IFR Approach Chart: A Quick Tour

Every approach plate consists of the following four sections:

• Approach Briefing Strip
• Plan View
• Profile View
• Landing Minimums

息息相传, check out what each section entails.

Approach Briefing Strip: Learn Smart, Fly Smart

Whenever you scrutinize an approach plate, your first task is to confirm that you're looking at the correct chart. To do this, peep at the large letters on the top and bottom right that indicate the approach type and the airport name.

Your next step is to ensure the chart is valid. You can find the validity period in the side margins of the FAA charts.

Once you're confident that you're examining the correct chart, delve into the briefing strip.

Airport/Runway Information Box: Basic But Important

This section serves as a brief rundown of essential information about the approach, including the approach course, the accessible landing distance, and the airport and touchdown zone elevations.

Utilize this box to assess whether the approach will be suitable for your plane and entry course. Most approaches rely on one primary NAVAID (Navigation Aid), and the identifier, and frequency, are presented here for convenience.

Requirements, Limitations, and Notes: Rules to (Safely) Play By

This section lists the equipment required to operate the approach, any limitations, and restrictions you must adhere to. Since this example chart showcases an ILS (Instrument Landing System) or LOC (Localizer) approach, it's a given that your aircraft needs a working ILS receiver.

However, check out the requirements section, and you'll notice you require Distance Measuring Equipment (DME) if entering from a particular waypoint. The notes section informs you of what to do in specific conditions, such as when the visibility requirements increase if the runway approach lights are not functioning.

The notes box can also include symbols to signify situations where standard rules don't apply. Here's what they mean:

• The A Triangle: This airport or runway has non-standard alternate minimums. If you opt for this airport as an alternate, check the airport minimums section in the Terminal Procedures Publication (TPP).
• The T Triangle: This airport or runway has non-standard takeoff minimums. Peruse the airport in the TPP's Takeoff Minimums and Departure Procedures section.
• The Snowflake Symbol: Icy condition- alert! If the temperature drops below the limit, apply altitude corrections for cold temperatures.

Decoding the Plan View: Picture Your Way Through

Simply put, the plan view resembles a map with arrows depicting the route of the approach. Here's how to make heads and tails of it all.

Understanding Fixes: Navigating Like a Pro

The initiation of an approach commences when reaching the Initial Approach Fix (IAF). The plan view marks these points as IAF above the fix identifier.

Progressing beyond the IAF ushers you into the initial approach phase. Many approaches include fixes in between called Intermediate Fixes (IF). If present, the plan view will mark them as IF.

Intersections at fixes are labeled INT. They present the DME distance in a D symbol. These intersections help you cross-check your position. For example, if you're undertaking the approach shown, you can confirm reaching the fix RRTOO if your DME shows 7.9 and you are on the 233 radial from the CWK VORTAC.

Altimeter Readings: Maintaining Altitude Awareness

Many approaches have altitude or airspeed restrictions at specific fixes. The plan view shows these as numbers underneath the fix name.

• When a number is underscored, you need to fly at or above that altitude.
• When a number is overscored, you must fly at or below that altitude.
• When a number is underscored and overscored, it's a mandatory altitude.

If you're flying a non-precision approach, like a localizer approach, heed step-down altitudes. When flying a precision approach, adhere to the restrictions only until you intercept the glideslope.

Some fixes have airspeed limitations as well, and these are represented similarly to altitude restrictions in the plan view.

MSA: Emergency Alert Sign

FAA charts depict an MSA (Minimum Safe Altitude) circle in the plan view. The MSA circle guarantees 1,000 feet of obstacle clearance when employed in emergencies.

The MSA circle centers around the primary NAVAID for the approach, and it segments the surrounding airspace up to 25 NM from the airport. Every segment boasts its MSA label.

Missed Approach Inset: Fallback Plan

The missed approach section starts beyond the missed approach point. The plan view illustrates this as dashed lines leading out from the runway.

For most approaches, the fix for the missed approach holding point is too distant from the airport. Therefore, the plan view illustrates the missed approach hold in an inset.

When you witness a dashed line leading out from the boundary, no worries! Peek for the inset to find where the holding fix is situated.

Breaking Down the Profile View: Charting a Course

The profile view offers a side-on perspective of the approach, making the descent path easier to understand. This view commences at the IAF and depicts the same waypoints as the plan view down to the missed approach segment.

Final Approach Fix: Precision Points

One of the profile view's essential features is that it marks the Final Approach Fix (FAF) distinctively.

• Precision approaches, such as ILS, employ a jagged arrow to mark the FAF. This is the juncture where you should intercept the glideslope.
• Non-precision approaches, such as a localizer, employ a Maltese cross ✠ for the FAF. Once at this point, begin your descending towards the Minimum Descent Altitude (MDA).

These two icons are not always adjacent. Always follow the icon that aligns with the type of approach you're piloting.

VDP: Visual Descent Aid

You'll notice a bold V on many straight-in non-precision approaches. This symbol represents the Visual Descent Point (VDP). If you encounter the runway by the VDP, you're authorized to descend beneath the MDA. This will help you establish a stable, controllable descent to the runway.

Missed Approach Point: Final Decision Point

The Missed Approach Point (MAP) is the final point at which you must make a decision on whether or not to touch down or execute a missed approach.

Precision Approaches: Continuous Descent

When you're piloting a precision approach, your descent remains continuous. The DA becomes your missed approach point. That's why the profile view for precision approaches doesn't have a specified missed approach point marked.

The solid approach path line merely changes into the dashed missed approach path line.

Non-Precision Approaches: Stepped Descent

During a non-precision approach, you cease your descent when you reach the MDA. Maintain altitude here until you reach the MAP.

Since the MAP is a designated point for non-precision approaches, it's easy to identify here.

The crucial tip to recognizing the MAP is acknowledging where the solid approach path line shifts to the dashed missed approach line.

Missed Approach Icons: SOS Signals

As in the previous sections, the profile view also offers guidance for implementing the missed approach. Here, the instructions are laid out in an inset using graphical cues.

While the inset isn't always comprehensive, you can learn to interpret these symbols during practice. For example, this approach describes the following sequence:

• Climb to 1,000 feet, then conduct a climbing left turn to 3,000 feet and set a heading of 040 degrees. Continue flying on the 088 radial from the CWK NAVAID until reaching the intersection HOOKK.

Understanding the Minimums Section: Essential Details

The previous sections mentioned descending to DA or MDA but failed to specify these altitudes for this approach. The minima table provides these critical altitudes, as well as the minimum visibility requirements for the approach.

Let's dive into the data found in the table.

Aircraft Categories

The columns in the minima table signify aircraft categories, categorized according to their approach speed, specifically V.

Slower-moving aircraft have a wider turning radius and lower minima. Category A, for instance, includes planes such as the Cessna 172 or the Piper PA-28.

Approach Types

Different approaches carry different minima based on the type of guidance they offer and their accuracy.

• Precision approaches, such as ILS, have the lowest minima.
• Non-precision approaches, such as the localizer approach mentioned earlier, have slightly higher minima.
• Circling approaches boast the highest minima compared to other instrument approaches since they demand visual contact with the airport while circling to land.

Understanding Landing Minima

Allow us to elucidate an example minima from the table:

1. The minima for the 18L ILS approach is 692/18 200 (200-1/2)
2. The first number, 692 feet, denotes the DA.
3. 18 is the visibility (RVR in hundreds of feet). That equates to an RVR of 1800 feet.
4. 200 feet is the HAT. This abbreviation stands for Height Above Touchdown Elevation. This value indicates that you'll be 200 feet above the runway when you decide whether to continue the approach or go around.

Let's consider another example from the table:

1. The circling minima for Category A is 1041-1 498 (500-1)
2. The first number, 1041 feet, signifies the MDA (since circling approaches are non-precision).
3. The second number, 1, denotes the required visibility in statute miles.
4. 498 is the HAA or Height Above Airport.

You may ponder why we haven't considered the numbers in the parentheses. These numbers are not applicable to civilian pilots; they are intended for the military, who follow their own regulations.

Remember, minima in this section can become invalid if the situation matches one of the conditions stated in the notes section on the briefing strip.

For example, if the approach lighting system is out, you'll need to abide by the visibility limits written in the notes for the approach.

Conclusion: Mastering the IFR Approach Chart

Once you've learned to read IFR approach charts, you transform these intricate diagrams into invaluable tools. Make it a point to familiarize yourself with each section - the briefing strip, plan view, profile view, and landing minimums.

Remember, these charts provide guidance and offer information for every phase of your approach, ensuring you have the information you need to navigate safely and confidently when relying on instruments in poor visibility conditions.

If you wish to delve further into IFR approaches, peruse our aircraft instruments course. Additionally, we recommend reviewing the documentation provided by the FAA on instrument approaches.

In the realm of aviation and transportation, navigating IFR approach charts is essential to execute a safe approach within the aerospace industry. These important documents, called Instrument Approach Procedure (IAP) charts, serve various purposes during a flight. Among pilots, they are commonly referred to as approach plates.

When embarking on an IFR approach, it is crucial to monitor multiple facets, such as the route, descent profile, missed approach procedure, communication frequencies, approach minima, airport details, and more. Fortunately, those details can be gleaned from the approach plate's four sections: Approach Briefing Strip, Plan View, Profile View, and Landing Minimums. So, let's dive into each section for a thorough understanding.

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