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What is the Visual Descent Point (VDP) on a non precision approach? The little black V on some approach plates causes a lot of big arguments. Learn about it here.
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Visual Descent Point (VDP): What is it Exactly? – PilotMall.com
The visual descent point (VDP) is a reference point used by pilots who are flying a non-precision instrument landing. This point lies at the minimum descent …
Source: www.pilotmall.com
Date Published: 1/24/2021
View: 4860
What is a Visual Descent Point (VDP)? – Aero Corner
The Visual Descent Point (VDP) is a point that tells the pilot when to descend below the Minimum Descent Altitude (MDA), even if they can’t see the runway.
Source: aerocorner.com
Date Published: 5/14/2022
View: 5063
What Is Visual Descent Point (VDP) – SkyTough
The visual descent point (VDP) is a key concept in aviation, and it’s something that every pilot needs to understand. The VDP is the point on an …
Source: www.skytough.com
Date Published: 8/9/2022
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Should You Go Missed If You Fly Past The VDP On An …
Visual Descent Point (VDP), Defined … According to the AIM, “the VDP is a defined point on the final approach course of a non-precision straight …
Source: www.boldmethod.com
Date Published: 9/6/2021
View: 465
Library Contents – FAA – FAASTeam – FAASafety.gov
The Visual Descent Point (VDP) is a defined point on a straight-in, non-precision approach from which you can descend below the MDA, as long as you have the …
Source: www.faasafety.gov
Date Published: 11/17/2022
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Instrument Tip: Going visual – AOPA
The visual descent point (VDP) is a tool to stop the madness and bring some stability to nonprecision approaches. Missed approach points are …
Source: www.aopa.org
Date Published: 12/20/2022
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Visual Descent Point (VDP) – Aviation Glossary
Visual Descent Point (VDP): A defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from …
Source: dictionary.dauntless-soft.com
Date Published: 5/10/2022
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Using a VDP – BruceAir, LLC – WordPress.com
Most IFR pilots and students can entify a visual descent point (VDP) on the profile view of an instrument approach chart, as highlighted on …
Source: bruceair.wordpress.com
Date Published: 11/17/2021
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Visual Descent Points (1983)
A Visual Descent Point is found by subtracting the touchdown zone from the Minimum Descent Altitude and diving the result by 300. Everything …
Source: code7700.com
Date Published: 11/8/2022
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주제에 대한 기사 평가 what is a visual descent point
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What is the purpose of a visual descent point?
The visual descent point (VDP) is a tool to stop the madness and bring some stability to nonprecision approaches. Missed approach points are often near the end of the runway. This gives you the latitude to drop down to the minimum descent altitude and then drone along until the bitter end.
How do you find the visual descent point?
The formula for calculating the VDP is simply the MDA divided by the normal rate of descent. So, if the MDA is 500 feet and the normal rate of descent is 400 ft/nm, then the VDP would be at 0.75 nautical miles from the runway threshold.
Is VDP mandatory?
The VDP is a great way to fly a stabilized approach from MDA to the runway, but it’s not a legal requirement for going missed.
What is a visual descent angle?
Visual Descent Angles (VDAs) are the angle between the runway threshold at the crossing height (TCH) and the minimum altitude at the final approach fix. Stepdown fixes are normally located so the VDA crosses the fix at or above the fix minimum altitude.
What is the difference between PDP and VDP?
Well-Known Member. As previously said, VDP can either be charted or derived from a formula (HAT/300). A PDP is a planned descent point, and isn’t a specific angle.
What does RVR mean in aviation?
The RVR (Runway Visual Range) is required to support precision landing and takeoff operations in the NAS . The system measures visibility, background luminance, and runway light intensity to determine the distance a pilot should be able to see down the runway.
What is a MOCA in aviation?
Minimum Obstruction Clearance Altitude (MOCA). The MOCA is the lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments that meets obstacle clearance requirements for the entire route segment.
What is LOM in aviation?
Locator outer marker
An LOM is a navigation aid used as part of an instrument landing system (ILS) instrument approach for aircraft. Aircraft can navigate directly to the location using the NDB as well as be alerted when they fly over it by the beacon.
What does MSA mean in aviation?
MINIMUM SAFE ALTITUDE (MSA)- The Minimum Safe Altitude (MSA) specified in 14 CFR Part 91 for various aircraft operations. Altitudes depicted on approach charts or departure procedure (DP) graphic charts which provide at least 1,000 feet of obstacle clearance for emergency use.
Can I descend below VDP?
The Visual Descent Point (VDP) is a defined point on a straight-in, non-precision approach from which you can descend below the MDA, as long as you have the required visual reference. If a VDP is available, it will be indicated by a “v” on the profile view portion of the instrument approach procedure chart.
Can I descend on a feeder route?
Once you are established (i.e. after FIXXX) you may descend in accordance with the published approach procedure. I have not experienced this, but an instructor brought up this possibility during a discussion on feeder routes.
Can you descend below MDA?
Here’s hoping that the weather is on your side. If the reported visibility at the airport is below published minimums, you may not be able to descend below the decision altitude (DA), decision height (DH), or minimum descent altitude (MDA) for the approach you’re attempting.
What is angle of descent?
Angle of descent is the angle between the longitudinal axis of pubic bone and a line joining the lowest edge of the pubis to the lowest convexity of the foetal skull.
What is the difference between DA and MDA?
As the names suggest, DA is a decision point while MDA is the lowest altitude allowed without visuals. The difference between DA vs MDA is reflected in the regulations, Practical Test Standards (PTS, soon Airman Certification Standards) and TERPS.
When can you descend on an ILS?
If you can see the white approach light system and nothing else, you can descend down to 100′ above touchdown zone elevation, regardless of the type of approach you’re flying (even if it’s a non-precision approach). But at the 100′ point, you need other visual references to descend lower.
What is LOM in aviation?
Locator outer marker
An LOM is a navigation aid used as part of an instrument landing system (ILS) instrument approach for aircraft. Aircraft can navigate directly to the location using the NDB as well as be alerted when they fly over it by the beacon.
What does MSA mean in aviation?
MINIMUM SAFE ALTITUDE (MSA)- The Minimum Safe Altitude (MSA) specified in 14 CFR Part 91 for various aircraft operations. Altitudes depicted on approach charts or departure procedure (DP) graphic charts which provide at least 1,000 feet of obstacle clearance for emergency use.
What is the difference between DA and MDA?
As the names suggest, DA is a decision point while MDA is the lowest altitude allowed without visuals. The difference between DA vs MDA is reflected in the regulations, Practical Test Standards (PTS, soon Airman Certification Standards) and TERPS.
Visual Descent Point (VDP): What is it Exactly?
Pilots flying a precision instrument approach have both course and glidepath deviation data to guide them the whole way down. But what guides a non-precision approach and how do pilots flying that type of approach know when and where to begin their final descent so they can execute a safe landing? The visual descent point is part of that equation.
What is a Visual Descent Point (VDP)?
The official AIM definition of a Visual Descent Point or VDP is “a defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the approach threshold of that runway, or approach lights, or other markings identifiable with the approach end of that runway are clearly visible to the pilot.”
As a refresher, in the above definition, the MDA is the minimum descent altitude – the lowest altitude to which you can descend on final during a standard instrument approach procedure (SIAP) with no electronic glideslope provided.
During your descent, you must remain at or above the minimum descent altitude until you have the necessary visibility to safely descend and you have acquired one of the approved visual references. You must also be in position to make a “normal” (read: not unsafely steep) descent. The visual descent point is the position from which you can descend from MDA while maintaining a 3-degree glidepath and landing at the touchdown point.
Types of Instrument Approach Procedures
When you are on a final approach and are setting up for landing, you need a controlled, orchestrated means of coordinating both your course and glidepath during the descent so that you land safely at the touchdown point on the runway.
For pilots who are flying under Instrument Flight Rules (IFR), there are three types of terminal instrument procedures (TERPS) or instrument approach procedures (IAPs) that can be used during an instrument landing.
Precision Approach (PA)
A precision approach (PA) is, as one would expect given the name, the most precise. It uses a navigation system that supplies both course and glidepath deviation data. An ILS (Instrument Landing System) is commonly used to guide precision approaches.
Approach with Vertical Guidance (APV)
The second type of TERPS is the approach with vertical guidance (APV). The navigation system used for an APV approach provides both course and glidepath deviation data similar to the PA, but not to such a carefully calibrated standard. Therefore, the vertical guidance supplied by an APV is less precise than that of a PA. Approach with Vertical Guidance is supported by LNAV/VNAV systems.
Non-Precision Approach
The final type of TERPS is the non-precision approach (NPA). For this instrument-based approach, the pilot’s navigational system provides feedback on course deviation, but no data on glidepath deviation. The VOR system is commonly used to support and guide non-precision approaches.
A Continuous Descent Final Approach (CDFA) is the newer, preferred method of guiding descent rate on a non-precision approach and CDFAs have been published for most non-precision approaches. Where a CDFA is not available, pilots can land using a step-down approach or the “dive and drive” method of descending to the minimum descent altitude immediately upon reaching the final approach fix (FAF).
In either the CDFA or the dive and drive method, the visual descent point (VDP) is located on the glidepath and plays a key role in guiding the landing process.
What is the purpose of the Visual Descent Point (VDP)?
Making a non-precision approach can be dangerous. The FAA and NTSB have identified unstabilized approaches to be one of the key contributing factors to non-precision approach accidents.
When executing a non-precision approach, some of the potential dangers include:
Diving too steeply and being unable to pull up to level off
Hitting an obstacle while descending
Going below the minimum descent altitude (MDA) too soon
Landing beyond the safe landing point
By beginning your final descent from the minimum descent altitude (MDA) as you reach the visual descent point and acquire visual reference, you will normally put yourself on a 3-degree glide path to the touchdown point. This is the same glideslope used by most precision approaches. Using the visual descent point to begin your final descent helps you to avoid a too steep or too shallow final descent angle.
How do you find the Visual Descent Point (VDP)?
If published, the Visual Descent Point (VDP) is identified with a “V” on the vertical profile of many approach plates. Pilots can also calculate it manually. If you need to manually determine the location of the VDP for your approach, use the below equation which will give you the distance from the touchdown point to the visual descent point in nautical miles (nm).
Note that the above equation is a “rule of thumb” pilot math estimation which assumes roughly 300 feet per nautical mile for a 3-degree glidepath. The actual trigonometric value is 318 feet, but the easier to work with estimation is only 18 feet or 6% off, and that is sufficiently accurate and conservative for the purposes of calculating VDP. The height above touchdown or HAT, should be indicated on your chart and can be calculated using:
Once you know the distance from the visual descent point to the touchdown zone, you can subtract the distance from the runway threshold to the touchdown zone. This gives you the VDP’s distance from the approach end of the runway.
In most cases, you will use your distance measuring equipment (DME) to alert you to the location of the VDP. If your DME is inoperable, it is recommended to fly the approach as though a VDP was not provided since you have no equipment to locate it.
A visual glide slope indicator (VGSI) can also be used as a visual aid for pilots flying a non-precision instrument approach. Note that if visibility is at or just above minimums, pilots may be unable to view the VGSI when they reach the visual descent point since the VGSI is located past the missed approach point (MAP).
It is important to realize that in many cases, if the VDP is not published, it is because there are terrain or other obstacles that could interfere with a safe descent. In this case, calculate your visual descent point location, but be absolutely certain that you have enough visibility to see any potential hazards before you begin your descent from MDA. If known obstacles are present, the chart will state “visual segment – obstacles” to alert you that you may need to modify your approach to avoid hazards.
What happens if you miss the Visual Descent Point (VDP)?
Remember that to be cleared to descend below the minimum descent altitude, the following three criteria must be met:
Be in a continuous position to make a normal descent and land on your intended runway
Have the necessary visibility to safely descend
Have the runway environment in sight
If all the above criteria are met, you can begin your descent upon arriving at the visual descent point. If not, you must not drop below the MDA until the criteria are met. If the criteria are not met by the time your reach the visual descent point, this is referred to as missing or flying past the VDP.
If you miss the visual descent point, you can technically continue flying at the minimum descent altitude (MDA) until you reach the missed approach point (MAP). If you are still lack the visibility, are out of position, or are unable to pick up at least one of the visual reference points and begin your final descent by the time you reach the MAP, then you must execute a missed approach procedure and do a go around. Never begin your descent from minimum descent altitude (MDA) beyond the missed approach point (MAP). First, it is illegal, and second, your angle will be too steep, or your touchdown point will be shifted too far down the runway for safety.
For added margin, some pilots like to use the visual descent point as a missed approach point. By making the decision to call a missed approach if they do not have enough visibility, are out of position, or cannot see their visual indicators at the VDP, pilots give themselves plenty of time to abort the landing attempt prior to passing the missed approach point.
Ultimately the decision of whether to call a missed approach at the VDP or at the MAP is up to the pilot. If you are unable to descend at the VDP because you do not meet the three necessary criteria, but conditions improve and you meet the criteria prior to arriving at the MAP, it is within pilot discretion to continue landing. Realizing that any descent begun beyond the visual descent point will be steeper than the normal 3-degrees, pilots must take into account their airplane type, configuration, speed, altitude, descent rate, rate of turn, and runway length, then make an appropriate decision. When in doubt, err on the side of caution and call missed.
Can you descend below the minimum descent altitude before reaching the VDP?
There has been much debate between pilots regarding whether you absolutely must wait until you reach the visual descent point before you descend below the MDA or whether waiting until the VDP is merely a guideline and suggestion that pilots are free to disregard if the situation warrants.
The AIM wording in CFR 91.175 c3 regarding when pilots can descend below the MDA confirms that pilots may descend only when they have meet the three criteria for descent below MDA. It does not specify anything about how that relates to the visual descent point.
In their Descent to MDA or DH and Beyond publication, however, while describing when to descend, the FAA specifically states, “Do not descend below MDA before reaching the VDP.”
Takeaways
The visual descent point (VDP) is a reference point used by pilots who are flying a non-precision instrument landing. This point lies at the minimum descent altitude (MDA) and indicates the position from which the pilot may begin a final descent for landing provided they are in position to land, have the necessary visibility, and have acquired visual references with the runway environment. A continuous rate of descent from the VDP to the touchdown point will usually set the pilot up with the same 3-degree glideslope used by pilots flying a precision approach.
If you are not in position, do not have the visibility, and/or you have not acquired visual references by the time you reach the visual descent point, you can continue flying at the minimum descent altitude until you reach the missed approach point (MAP) at which time you must call a missed approach and execute a go-around. Depending on their aircraft, experience level, and conditions, some pilots choose to fly more conservatively and call missed if they are unable to descend upon reaching the visual descent point rather than waiting until they arrive at the missed approach point.
Pilots may descend below the minimum descent altitude at the visual descent point or between the visual descent point and the missed approach point if they are able to do so safely. The FAA instructs pilots to avoid descending below the minimum descent altitude until they have reached the visual descent point. This helps minimize the risk of impacting terrain and obstacles due to an early descent.
A solid understanding of the purpose, location, and use of the visual descent point will help IFR pilots flying a non-precision approach to do so in a safe, smooth manner. Review your instrument approach procedures and other IFR specifics with the Instrument Pilot Handbook. For a clear, straightforward visual presentation of understanding and using the visual descent point, watch Larry Epley’s quick and concise VDP explanation.
Read more about Visual Descent Point (VDP) and other flight training topics in our Flight Training Material: Private Pilot collection.
Instrument Tip: Going visual
It seems that for forever, the advice was to chop the power at the final approach fix and dive for the minimum descent altitude, with the goal of seeing the runway as early as possible, and then starting a descent.
The visual descent point (VDP) is a tool to stop the madness and bring some stability to nonprecision approaches. Missed approach points are often near the end of the runway. This gives you the latitude to drop down to the minimum descent altitude and then drone along until the bitter end. If you don’t see the runway, the decision to start the missed approach is easy. But what if you do see the runway? Now you have to decide if you want to dive down in order to make it. In a slow, draggy airplane, this might not be a problem. But as you step up to bigger and faster airplanes, it’s easy to see how you could skid off the end of the runway in such a scenario.
The VDP is a marker on the approach from which a normal descent and landing can be made, and in certain applications takes away the needs for such a hasty last-minute decision. It generally reflects the intersection of a 3-degree glideslope with the missed approach altitude.
When you arrive at the VDP you have three options:
Ignore it. The VDP isn’t the missed approach point. There’s no requirement that you do anything at the VDP, so you have the option to keep buzzing along until you reach the MAP. Start a descent. The VDP does not give you a clearance to descend below the minimum descent altitude before seeing the runway. It’s not a license to ignore the requirements of FAR 91.175 (the conditions by which you’re allowed to descend below the minimum descent altitude). But, if you’ve already broken out of the clouds and the visibility is good enough that you can see the runway, the VDP is a good point from which to begin the final descent to the runway. Even though it isn’t regulatory, it’s also good to think of the VDP as the absolute initial point of the final descent. As the Aeronautical Information Manual says, “The pilot should not descend below the MDA prior to reaching the VDP.” Go missed. Although we’re trained to continue an approach to the missed approach point, there’s nothing that says we can’t break it off early. Doing so could be the safest course of action. If you think of the VDP not as a point from which a decent can begin, but instead as the primary missed approach point, you’ll never be faced with the choice of whether or not to dive for the runway at the last moment. Rather, when you don’t see the runway at the VDP, begin the missed approach, knowing that you can’t make a normal stabilized approach beyond that point.
Not every nonprecision approach has a VDP. If an obstruction rises into the visual segment of the approach, a VDP won’t be published, for example. In these cases you can mentally create your own VDP by taking the difference between the minimum descent altitude and the touchdown zone elevation and dividing by 300. This will give you a general point at which to begin the descent or go missed, but remember that the absence of the VDP may mean there’s an obstruction to avoid. Also keep in mind that for this calculation you are looking for distance from the end of the runway, not the GPS center point or DME of the airport. Usually these are in the middle of the airport. You may need to subtract this distance from your VDP to make sure you end up with a stabilized approach to the runway and not a phantom marker in the middle of the airport.
With the VDP there’s no longer a reason to dive for the runway at the missed approach point. Especially in instrument conditions, stability is the goal, and a VDP offers just that.
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What Is Visual Descent Point (VDP)
SkyTough has quickly become one of the leading aviation sites on the web by focusing on producing high-quality content that our readers actually want to read. All of the information that we post has been thoroughly researched and vetted so that you can read with the confidence you’re getting accurate information. By the time you’re done reading this, you’ll know all about the VDP.
In this article, we will explain everything you need to know about the VDP. We’ll discuss what it is, how to find it on approach plates, and how to use it safely during a landing. We’ll also talk about what happens if you miss the VDP. So if you’re ready to dive in and learn about this vital part of non-precision approaches, then strap in and continue reading!
The Visual Descent Point (VDP) is an important part of any non-precision instrument approach. It’s a point on the approach where the aircraft should be at or below the minimum descent altitude. Pilots use the VDP to help them make a safe landing, even if they can’t see the runway.
Knowing how to make safe approaches and landings is without a doubt one of the most important parts of becoming a pilot. As you get more and more advanced in your flying, you’ll eventually start making non-precision approaches where you don’t have as much data to rely on as other planes might provide. That’s where the Visual Descent Point comes in.
While making a non-precision approach, you’ll need to know what the Visual Descent Point is. Learn everything about the VDP in aviation in this expert guide.
What is a Visual Descent Point (VDP) in Aviation?
When you take a look at some non-precision approach plates, you’ll see a small black “V”, often on the localizer approach section of the plate. But what is this little black “V” and what does it really mean? This is the Visual Descent Point (VDP), and it’s one of the most misunderstood and misused aspects of approach plates.
So what is the VDP?
Let’s start by taking a look at the official definition from the Federal Aviation Administration (FAA). In Section 4 of the Aeronautical Information Manual (AIM), Arrival Procedures are outlined in detail. Subsection 5-4-5 Instrument Approach Procedure (IAP), paragraph (h) details exactly what the VDP is.
According to the AIM, the VDP is a “defined point on the final approach course of a nonprecision straight-in approach”. Right off the bat, this means that you won’t have to worry about the VDP on a circling-only approach since it’s only used for straight-in approaches.
The AIM goes on to say that it’s the point from which a stabilized descent from the MDA to the decision height (DH) or touchdown can be made using normal landing configuration and approach speed. So basically, it’s the point where you should be able to see the runway and make a normal landing.
Now that we know what the VDP is, let’s talk about how to find it on an approach plate.
How to Find the Visual Descent Point (VDP)
The VDP can be found on the final approach fix (FAF) or localizer back course (LBC) segment of non-precision approach plates. It will be marked with a small black “V” and will have a corresponding note next to it. This note will give you the decision altitude (DA), which is the same as the decision height (DH) on a precision approach.
The VDP will also have a minimum descent altitude (MDA) associated with it. This is the lowest altitude that you can go down to and still maintain visual contact with the runway. If you can’t see the runway at the MDA, then you must go around and try again.
Now that we know what the VDP is and how to find it on an approach plate, let’s talk about how to use it during a landing.
How Can Pilots Calculate the VDP on the Fly?
Now that we know what the VDP is and how to find it on an approach plate, let’s discuss how pilots can calculate the VDP on the fly. This is important because sometimes the VDP isn’t explicitly called out on an approach plate and pilots need to be able to calculate it themselves.
There are two main variables that go into calculating the VDP: the MDA and the rate of descent. The MDA is simply the minimum altitude that you’re allowed to descend to on an approach. This is usually given in feet above mean sea level (MSL). You can find the MDA on the approach plate under the “Descend” or “Initial Descent” heading.
The rate of descent is a bit more complicated. There are two different rates of descent that you need to be aware of: the normal rate of descent and the maximum rate of descent. The normal rate of descent is simply the average rate at which you’ll descend on an approach. This is usually given in feet per nautical mile (ft/nm). You can find the normal rate of descent on the approach plate under the “Rate” or “Normal Descent” heading.
The maximum rate of descent, on the other hand, is the fastest rate at which you’re allowed to descend on an approach. This is usually given in feet per minute (ft/min). You can find the maximum rate of descent on the approach plate under the “Max Descent” or “Maximum Descent” heading.
Now that we know all of the variables that go into calculating the VDP, let’s put it all together. The formula for calculating the VDP is simply the MDA divided by the normal rate of descent. So, if the MDA is 500 feet and the normal rate of descent is 400 ft/nm, then the VDP would be at 0.75 nautical miles from the runway threshold.
It’s important to note that you should always use the normal rate of descent when calculating the VDP. The maximum rate of descent is only to be used if you’re descending at a faster rate than normal for some reason (e.g., you’re trying to make up for lost time).
Why is it Important to Understand What the VDP is?
The visual descent point (VDP) is a key concept in aviation, and it’s something that every pilot needs to understand. The VDP is the point on an approach plate where the pilot begins their final descent towards the runway. This point is calculated based on the aircraft’s rate of descent, and it’s marked on the approach plate so that pilots can easily find it.
The VDP is used on non-precision instrument approaches, and it’s a key part of making a safe and successful landing. If you miss the VDP, you may not have enough time or altitude to make a proper landing. That’s why it’s so important to understand how to calculate the VDP and where to find it on approach plates.
Here’s a quick overview of what you need to know about the VDP:
The VDP is the point on an approach plate where the pilot begins their final descent towards the runway.
It is calculated based on the aircraft’s rate of descent and MDA.
The VDP is marked on the approach plate so that pilots can easily find it.
This point is used for straight-in non-precision instrument approaches.
If you miss the VDP, you may not have enough time or altitude to make a proper landing.
With such a technical concept as the VDP, it’s best if you go and check out an approach plate yourself after this to see if you can apply the concepts you just learned here. At the very least, keep these bullet points in mind and you’ll know more about the VDP in aviation than the vast majority of people out there!
Should You Go Missed If You Fly Past The VDP On An Instrument Approach?
You’ve passed the VDP on an instrument approach, and you start to see the runway, but you’re high. What should you do?
Visual Descent Point (VDP), Defined
According to the AIM, “the VDP is a defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced.”
VDPs are only published for straight-in instrument approaches to specific runways, and if your approach has one, you shouldn’t descend below MDA prior to reaching the VDP.
When you reach VDP, you’ll typically be able to follow a 3-degree glide path to the runway, which is the same glide path as most precision approaches.
So how do you know if your approach has a VDP? It’s denoted by a bold V, like the image below.
What To Do If A VDP Isn’t Published
When instrument procedure designers survey land during the creation of an approach, they’ll analyze what obstructions penetrate safety clearance tolerances. If obstructions are present, a VDP might be denied during the creation of the instrument approach. This is why you won’t find a “V” published on every non-precision approach, like the image below.
If that’s the case, you can use a rule-of-thumb to find the approximate distance where you would start a descent from MDA to the runway: Take the AGL value of the MDA and divide it by 300.
For example, on the Crookston (KCKN) VOR/DME Approach to Runway 13, the lowest MDA takes you to 344 feet above the TDZE. Divide this by 300, and you’ll get 1.15, which is the approximate distance from the runway where you can start a 3-degree descent to the runway.
Remember that the resulting value is NOT DME. It is the VDP’s distance from the runway. You’ll need to add or subtract this from DME readings to properly locate your descent point.
And there’s another thing to keep in mind. In many cases, the VDP wasn’t published because of terrain or obstacles. Before you start your descent down from MDA to the runway, be sure you have enough visibility not only see the runway, but also see any obstructions that might be in your path (more on this in a bit).
What Is “Continuous Position To Land”?
VDP does not define a point necessary for a “continuous position to land” under FAR 91.175. A variety of descent angles can provide you with a stabilized approach, which is important for a safe descent below MDA.
Click here to learn when you can go below minimums on an instrument approach.
You Just Flew Past VDP. Now What?
If you flew past VDP because the required items for descent weren’t met, but you’re not to the missed approach point yet, you’re faced with a decision: Should you plan to go missed? Should you continue to the MAP?
The closer you get to the missed approach point at MDA, the higher the descent angle you need to get to the runway. However, if you see the runway environment past VDP, you may still be able to make a safe descent to landing.
Whether you can safely make a steeper than normal descent comes down to what kind of airplane you’re flying, your configuration, and the speed you fly the final approach segment at.
In something like a light, single-engine piston, you’ll have a lot more leeway than a jet. The faster you fly, the faster descent rate you’ll need to make the same descent angle work. Because of this, many pilots plan to go missed if the runway environment isn’t in-sight by the VDP.
No matter what you fly, you don’t want to put yourself in a situation where you need a rapid descent to make the runway. If you’re not used to flying steep, high descent-rate approaches in clear weather, attempting one when you’re shooting an approach in poor visibility isn’t a great idea.
That said, the VDP isn’t a required decision point (the required decision point is the missed approach point). The VDP is a great way to fly a stabilized approach from MDA to the runway, but it’s not a legal requirement for going missed.
How do you use VDP? Tell us in the comments below.
Protect your certificate with AOPA Pilot Protection Services. Learn more and get started here.
Advisory Glidepaths
What’s in Your Database?
Properly flying a continuous descent on approach requires a glidepath indication, which is computed based on the VDA and TCH values stored in a GPS database. We spoke to Jeppesen to learn about how they process instrument procedures into their aeronautical databases.
Jeppesen receives its US source data from the FAA and encodes the data in ARINC 424 format, the standard aeronautical data format used in aircraft. This data is then provided to vendors, such as Garmin. Although the format includes a lot of information, some of the details found on the actual approach chart are omitted – minimums, in particular – which is why pilots must still have a chart for the procedure being flown.
Jeppesen will include VDAs that are supplied in the source data, and compute then if not in the source data, unless the source data specifically deletes them by showing a zero angle as the FAA has begun to do. Jeppesen also ensures that supplied VDAs will meet all stepdown fixes. When the FAA’s VDA is computed based on a stepdown fix, Jeppesen data applies that VDA back to the altitude of the FAF. A pilot level at the published FAF minimum altitude will intercept this vertical angle after the FAF resulting in a delayed, but continuous, descent.
Inside Garmin Navigators
We also talked to Garmin about how they use the navigation data. Garmin receives navigation data from Jeppesen and converts it into a format for the actual devices in the cockpit. This is what you install.
Garmin requires specific conditions before the depict an advisory glidepath. Advisory glidepaths will only be displayed for GPS approaches (including overlay approaches) that have LNAV minimums and no charted LNAV/VNAV or LPV minimums. There is currently no support for advisory glidepath to LP minimums. The unit must also be receiving WAAS and integrity at the same level as is required for LNAV/VNAV minimums. Finally, the procedure must have a non-zero VDA. The last requirement means that LNAV+V will be unavailable for procedures that have had VDAs removed by the FAA.
Procedures that meet these criteria will depict a derived glidepath. Because the VDA is relative to the runway threshold and independent of the MAP or approach minimums, the glidepath is shown all the way down to the threshold. This is where pilots might get into trouble if they continue to follow the glidepath without regard to potential obstacles.
Why not discontinue display of a VDA below the MDA? Unfortunately, minimums are not included in the ARINC 424 source data. Additionally, the avionics could not know the applicable minimums for a given approach. The published minimums might be raised, for example by NOTAM or due to a remote altimeter source in use or even just circling vs straight in.
Glidepath Interpretation
Pilots must realize that once past the MAP, they are responsible for their own obstacle clearance and should not assume they will be safe on the glidepath, as they are with an ILS. Any glidepath provided on a non-precision approach is for advisory use only. The AIM reflects this, avionics manuals and aircraft flight manual supplements reflect this, yet it remains a source of confusion.
This is a classic human factors problem with pilots being pulled in conflicting directions. Many pilots have been conditioned to follow the glidepath by tears of flying ILSes and human nature is to remember best what we learned first. Since there are now glidepaths for advisory use only, it’s not surprising that a pilot under stress toward the end of an instrument approach might fall back onto their familiar ILS glidepath mindset.
At the same time, continuous descent final approaches on non-precision approaches offer very real safety benefits and are working their way into general aviation, as evidenced by LNAV+V capabilities in WAAS GPS navigators. How can we take advantage of the benefits of CDFA while avoiding obstacles if following an advisory glidepath below MDA is currently a hot topic within the FAA and industry; expect to hear more once the dust settles.
What is a Visual Descent Point (VDP)?
For most pilots, the most difficult part of flying is executing a safe landing. To help you, there are several tools you can use, the Visual Descent Point, or VDP, is one of them. But what exactly is it, and how can you use it?
The Visual Descent Point (VDP) is a point that tells the pilot when to descend below the Minimum Descent Altitude (MDA), even if they can’t see the runway. It is typically displayed on the profile view section of the approach chart with a “V”.
Brought about to improve pilot safety, the VDP is designed to prevent a pilot by descending too quickly and hitting an obstacle of some kind by remaining at the MDA until they have acquired one of the approved visual references.
FAA VDP visual Descent Point on RNAV approach
Why Is It Important to Know About the Visual Descent Point?
A visual descent point is an important tool in aviation and it is something every pilot needs to know about. It is a point on the approach chart where the pilot begins their final descent towards the runway. It enables the pilot to know when to start descending instead of using the usual “dive and drive” concept.
According to the FAA and the National Transportation Safety Board (NTSB), most accidents while making a non-precision approach are linked to an unstabilized landing process. This is why every pilot should know how to use the VDP.
It is also calculated based on the aircraft’s rate of descent and it is indicated on the chart so that pilots can easily find it.
Why Is the Visual Descent Point Not Published?
Knowing how to calculate the visual descent point is also an important factor to consider while flying because sometimes it is not called out on the approach chart and pilots will have to calculate it themselves.
Use the equation below to find the visual descent point if it is not published on the chart.
What we are trying to identify with the visual descent point is where the pilot will leave the MDA to be able to have a stabilized gliding of three degrees.
Visual descent point (VDP) = height above touchdown (HAT)300 feet
If the HAT is 562, divide it by 300, and you will get 1.88NM. This means that while descending from the final approach fix, you will get a three-degree glideslope to the runway when you get to 1.88NM.
Keep in mind that the above equation is a “rule of thumb.” This means that it is not based on the exact calculations. The accurate calculation is HAT divided by 318, but we use 300 because it is easier to understand.
It is important to know that if the VDP is not published, it is because there are obstacles like terrain that could interfere with a safe descent.
In this situation, calculate your visual descent point, but make sure you have enough visibility to see any potential risks before you begin your descent from the MDA.
If there are obstacles, the chart will display “visual segment obstacles,” indicating that you may need to change your approach to avoid risks.
What Happens if I Miss a VDP?
You can continue to fly when you miss the VDP at the minimum descent altitude till you get to the missed approach point.
But if you still lack visibility, or you are unable to pick up at least one of the visual reference points and begin your final descent by the time you reach the missed approach point, then you must turn around and execute a missed approach procedure.
Never start your descent from the minimum descent altitude (MDA) and go beyond the missed approach point (MAP) because it is prohibited and your touchdown point will be shifted too far down the runway for safety.
Keep in mind that some pilots like to use the visual descent point as a missed approach point. By deciding to call a missed approach if they do not have enough visibility or they are out of position, pilots give themselves enough time to abort the landing attempt before crossing the missed approach point.
Finally, it is up to the pilot to call a missed approach at the visual descent point or the MAP. If they are unable to descend at the visual descent point because they initially failed to meet the necessary criteria, but conditions changed and they met the criteria before arriving at the MAP, it is within the pilot’s decision to continue landing.
Given that any aircraft starting a descent before the visual descent point will not meet up to the standard three-degree glideslope, pilots must consider the type of airplane they use, its configuration, speed, descent rate, and runaway length before making a choice.
Is the VDP Mandatory?
The visual descent point is not a legal requirement; however, it is a good way to fly a stabilized approach from the MDA to the runway.
There are three options for you when you get to the visual descent point and they include:
Ignore it: The visual descent point is not the missed approach point and there is no rule that you do anything at the VPD. So, you have the option to keep moving until you reach the MAP.
The visual descent point is not the missed approach point and there is no rule that you do anything at the VPD. So, you have the option to keep moving until you reach the MAP. Start descending: The visual descent point does not permit you to go below the minimum descent altitude before you can see the runway. It is not legal to disregard the rules that guide you before descending below the MDA.
However, it is a suitable point to start your final descent to the runway if you’ve gotten through the clouds and you have enough visibility to see the runway.
Go missed: Although pilots are trained to continue an approach to the missed approach point, no rule says they can’t break it off early. It is possible that doing this might be the safest course of action.
If you think of the visual descent point as the primary missed approach point and not as a point from which a descent can begin, then you will not have the problem of choosing between diving or not diving for the runway at the last moment.
Is It Possible to Go Below the Minimum Descent Altitude Before Getting to the Visual Descent Point?
The question of whether you should wait until you get to the visual descent point before descending below the MDA has sparked much controversy among pilots. Or if it is only a guideline that pilots can ignore whenever they want.
According to the rules from the Code of Federal Regulations (CFR), pilots are only allowed to descend when they’ve met the necessary conditions for descent below the minimum descent altitude. It does not state anything about how that relates to the visual descent point.
However, while describing how to descend in a recent publication, the FAA states that you should not descend below the MDA before reaching the visual descent point.
What Are the Criteria for Descending Below the Minimum Descent Altitude?
You must meet the following conditions before you are eligible to descend below the minimum descent altitude.
Must have the necessary visibility to descend safely
Aircraft must be in a continuous position to make a normal descent and land on the intended runway
Must have the runway environment insight
You can start your descent when you reach the visual descent point if you meet all the above criteria. But if you did not, you must drop below the MDA until you meet all the criteria.
If you did not meet up to the criteria by the time you reach the visual descent point, it is referred to as missing or flying past the VDP.
Does a VDP Guarantee Obstacle Clearance?
Any approach with a visual descent point ensures a pilot’s safety from obstacles below the MDA to the runway threshold. While anyone without a visual descent point gives no assurance of the pilot’s safety from obstacles once they descend below the MDA.
What Is the Difference Between a Precision Approach and a Non-Precision Approach?
A precision approach uses a ground station and they send information about your position and your final approach. The benefit of flying a precision approach is that you have instant information about your position during the last part of the descent.
This is crucial because you get close to the ground and terrain in the last part of your final descent, so it helps maintain a stabilized landing procedure.
A non-precision approach on the other hand doesn’t have all the information that helps the pilot. What happens in a non-precision approach is that the pilot has close information.
For example, they might have a localizer that tells them if they are moving to the left or the right but they do not receive any information on their final approach.
The main challenge of flying a non-precision approach is that because you get so busy on the final stage of your flight, where you have to configure the plane, make sure you put the terrain and weather into account, you might get overloaded with work and this can lead to a major crash.
It is more challenging to descend while using a non-precision approach compared to a precision approach where you have all the information you need.
What Approaches Have a Visual Descent Point?
A visual descent point is a point on a straight-in, non-precision approach. It does not provide more value to other approaches because they have enough information that tells the pilot how to proceed at any time.
Related Posts
What Is Visual Descent Point (VDP)
SkyTough has quickly become one of the leading aviation sites on the web by focusing on producing high-quality content that our readers actually want to read. All of the information that we post has been thoroughly researched and vetted so that you can read with the confidence you’re getting accurate information. By the time you’re done reading this, you’ll know all about the VDP.
In this article, we will explain everything you need to know about the VDP. We’ll discuss what it is, how to find it on approach plates, and how to use it safely during a landing. We’ll also talk about what happens if you miss the VDP. So if you’re ready to dive in and learn about this vital part of non-precision approaches, then strap in and continue reading!
The Visual Descent Point (VDP) is an important part of any non-precision instrument approach. It’s a point on the approach where the aircraft should be at or below the minimum descent altitude. Pilots use the VDP to help them make a safe landing, even if they can’t see the runway.
Knowing how to make safe approaches and landings is without a doubt one of the most important parts of becoming a pilot. As you get more and more advanced in your flying, you’ll eventually start making non-precision approaches where you don’t have as much data to rely on as other planes might provide. That’s where the Visual Descent Point comes in.
While making a non-precision approach, you’ll need to know what the Visual Descent Point is. Learn everything about the VDP in aviation in this expert guide.
What is a Visual Descent Point (VDP) in Aviation?
When you take a look at some non-precision approach plates, you’ll see a small black “V”, often on the localizer approach section of the plate. But what is this little black “V” and what does it really mean? This is the Visual Descent Point (VDP), and it’s one of the most misunderstood and misused aspects of approach plates.
So what is the VDP?
Let’s start by taking a look at the official definition from the Federal Aviation Administration (FAA). In Section 4 of the Aeronautical Information Manual (AIM), Arrival Procedures are outlined in detail. Subsection 5-4-5 Instrument Approach Procedure (IAP), paragraph (h) details exactly what the VDP is.
According to the AIM, the VDP is a “defined point on the final approach course of a nonprecision straight-in approach”. Right off the bat, this means that you won’t have to worry about the VDP on a circling-only approach since it’s only used for straight-in approaches.
The AIM goes on to say that it’s the point from which a stabilized descent from the MDA to the decision height (DH) or touchdown can be made using normal landing configuration and approach speed. So basically, it’s the point where you should be able to see the runway and make a normal landing.
Now that we know what the VDP is, let’s talk about how to find it on an approach plate.
How to Find the Visual Descent Point (VDP)
The VDP can be found on the final approach fix (FAF) or localizer back course (LBC) segment of non-precision approach plates. It will be marked with a small black “V” and will have a corresponding note next to it. This note will give you the decision altitude (DA), which is the same as the decision height (DH) on a precision approach.
The VDP will also have a minimum descent altitude (MDA) associated with it. This is the lowest altitude that you can go down to and still maintain visual contact with the runway. If you can’t see the runway at the MDA, then you must go around and try again.
Now that we know what the VDP is and how to find it on an approach plate, let’s talk about how to use it during a landing.
How Can Pilots Calculate the VDP on the Fly?
Now that we know what the VDP is and how to find it on an approach plate, let’s discuss how pilots can calculate the VDP on the fly. This is important because sometimes the VDP isn’t explicitly called out on an approach plate and pilots need to be able to calculate it themselves.
There are two main variables that go into calculating the VDP: the MDA and the rate of descent. The MDA is simply the minimum altitude that you’re allowed to descend to on an approach. This is usually given in feet above mean sea level (MSL). You can find the MDA on the approach plate under the “Descend” or “Initial Descent” heading.
The rate of descent is a bit more complicated. There are two different rates of descent that you need to be aware of: the normal rate of descent and the maximum rate of descent. The normal rate of descent is simply the average rate at which you’ll descend on an approach. This is usually given in feet per nautical mile (ft/nm). You can find the normal rate of descent on the approach plate under the “Rate” or “Normal Descent” heading.
The maximum rate of descent, on the other hand, is the fastest rate at which you’re allowed to descend on an approach. This is usually given in feet per minute (ft/min). You can find the maximum rate of descent on the approach plate under the “Max Descent” or “Maximum Descent” heading.
Now that we know all of the variables that go into calculating the VDP, let’s put it all together. The formula for calculating the VDP is simply the MDA divided by the normal rate of descent. So, if the MDA is 500 feet and the normal rate of descent is 400 ft/nm, then the VDP would be at 0.75 nautical miles from the runway threshold.
It’s important to note that you should always use the normal rate of descent when calculating the VDP. The maximum rate of descent is only to be used if you’re descending at a faster rate than normal for some reason (e.g., you’re trying to make up for lost time).
Why is it Important to Understand What the VDP is?
The visual descent point (VDP) is a key concept in aviation, and it’s something that every pilot needs to understand. The VDP is the point on an approach plate where the pilot begins their final descent towards the runway. This point is calculated based on the aircraft’s rate of descent, and it’s marked on the approach plate so that pilots can easily find it.
The VDP is used on non-precision instrument approaches, and it’s a key part of making a safe and successful landing. If you miss the VDP, you may not have enough time or altitude to make a proper landing. That’s why it’s so important to understand how to calculate the VDP and where to find it on approach plates.
Here’s a quick overview of what you need to know about the VDP:
The VDP is the point on an approach plate where the pilot begins their final descent towards the runway.
It is calculated based on the aircraft’s rate of descent and MDA.
The VDP is marked on the approach plate so that pilots can easily find it.
This point is used for straight-in non-precision instrument approaches.
If you miss the VDP, you may not have enough time or altitude to make a proper landing.
With such a technical concept as the VDP, it’s best if you go and check out an approach plate yourself after this to see if you can apply the concepts you just learned here. At the very least, keep these bullet points in mind and you’ll know more about the VDP in aviation than the vast majority of people out there!
Should You Go Missed If You Fly Past The VDP On An Instrument Approach?
You’ve passed the VDP on an instrument approach, and you start to see the runway, but you’re high. What should you do?
Visual Descent Point (VDP), Defined
According to the AIM, “the VDP is a defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced.”
VDPs are only published for straight-in instrument approaches to specific runways, and if your approach has one, you shouldn’t descend below MDA prior to reaching the VDP.
When you reach VDP, you’ll typically be able to follow a 3-degree glide path to the runway, which is the same glide path as most precision approaches.
So how do you know if your approach has a VDP? It’s denoted by a bold V, like the image below.
What To Do If A VDP Isn’t Published
When instrument procedure designers survey land during the creation of an approach, they’ll analyze what obstructions penetrate safety clearance tolerances. If obstructions are present, a VDP might be denied during the creation of the instrument approach. This is why you won’t find a “V” published on every non-precision approach, like the image below.
If that’s the case, you can use a rule-of-thumb to find the approximate distance where you would start a descent from MDA to the runway: Take the AGL value of the MDA and divide it by 300.
For example, on the Crookston (KCKN) VOR/DME Approach to Runway 13, the lowest MDA takes you to 344 feet above the TDZE. Divide this by 300, and you’ll get 1.15, which is the approximate distance from the runway where you can start a 3-degree descent to the runway.
Remember that the resulting value is NOT DME. It is the VDP’s distance from the runway. You’ll need to add or subtract this from DME readings to properly locate your descent point.
And there’s another thing to keep in mind. In many cases, the VDP wasn’t published because of terrain or obstacles. Before you start your descent down from MDA to the runway, be sure you have enough visibility not only see the runway, but also see any obstructions that might be in your path (more on this in a bit).
What Is “Continuous Position To Land”?
VDP does not define a point necessary for a “continuous position to land” under FAR 91.175. A variety of descent angles can provide you with a stabilized approach, which is important for a safe descent below MDA.
Click here to learn when you can go below minimums on an instrument approach.
You Just Flew Past VDP. Now What?
If you flew past VDP because the required items for descent weren’t met, but you’re not to the missed approach point yet, you’re faced with a decision: Should you plan to go missed? Should you continue to the MAP?
The closer you get to the missed approach point at MDA, the higher the descent angle you need to get to the runway. However, if you see the runway environment past VDP, you may still be able to make a safe descent to landing.
Whether you can safely make a steeper than normal descent comes down to what kind of airplane you’re flying, your configuration, and the speed you fly the final approach segment at.
In something like a light, single-engine piston, you’ll have a lot more leeway than a jet. The faster you fly, the faster descent rate you’ll need to make the same descent angle work. Because of this, many pilots plan to go missed if the runway environment isn’t in-sight by the VDP.
No matter what you fly, you don’t want to put yourself in a situation where you need a rapid descent to make the runway. If you’re not used to flying steep, high descent-rate approaches in clear weather, attempting one when you’re shooting an approach in poor visibility isn’t a great idea.
That said, the VDP isn’t a required decision point (the required decision point is the missed approach point). The VDP is a great way to fly a stabilized approach from MDA to the runway, but it’s not a legal requirement for going missed.
How do you use VDP? Tell us in the comments below.
Protect your certificate with AOPA Pilot Protection Services. Learn more and get started here.
Library Contents
Call Flight Service When talking to an Automated Flight Service Station (AFSS) briefer, be sure to get all notices to airmen (NOTAMs) pertaining to your flight. These include local NOTAMs (NOTAM-L) for departure and destination, distant NOTAMs (NOTAM-D), and – vital for IFR flight – flight data center (FDC) NOTAMs. Be sure to get not only current NOTAMs, but also those already published in the bi-weekly NOTAMs. If you are using direct user access terminal (DUAT) for your weather briefing information, you will need to use a site-specific airport identifier to get FDC NOTAMs. It may be necessary to call the AFSS to be sure that you have the NOTAMs already published in the bi-weekly NOTAM publication. You might also want to call your destination airport to see if there are any special local “Letters to Airmen” that could affect your flight. Review Charts After obtaining a weather briefing and determining which runway is likely to be in use at your destination, review all possible approach charts. Be sure to note any obstructions and their location relative to the airport. Make sure that you have current enroute, approach, and sectional charts on board. It is not a good idea to switch back and forth between National Aeronautical Charting Office (NACO) and Jeppesen charts; choose one format and use it on a regular basis to ensure that you know exactly where to look for the information you need at any given time. An aircraft cockpit is not the place to familiarize yourself with a chart format that you are not accustomed to using! You will also want to have all of the approach charts for your destination airport (and also your alternate, if one is required) readily available. Trying to find the right chart when you are also flying the aircraft in instrument meteorological conditions (IMC), especially in single pilot operations, is not consistent with either good judgment or good planning. Know what your options are with respect to the approach procedures. If the ILS glideslope (GS) fails, are you ready to fly the localizer (LOC) approach? Are you proficient enough with your equipment to fly a GPS approach? Is your equipment legal to use on a GPS approach? Are you equipped — and proficient — enough for VOR/DME or NDB approaches? Think through these points in advance. If you do not have the equipment required or the training needed to fly one or more of the approaches at your destination, the best time to figure that out is on the ground. Now is a good time to ensure that all the navigational aids in your aircraft — VOR, GPS, DME, ADF — are working properly. LPV, LNAV, VNAV? With the advent of satellite navigation, instrument pilots today have a number of new terms to understand on instrument approach procedure charts. It is extremely important for you to understand what these terms mean, and whether your aircraft is equipped to use these minimums. The graphic below is from Figure 5-15 in FAA-H-8261-1, Instrument Procedures Manual.
It is a good idea to review the FAA Instrument Procedures Manual (FAA-H-8261-1) to be sure that you fully understand these terms, but here are a few definitions: RNAV: This term refers to “area navigation.” There are many different levels of authorizations for use of RNAV approach systems. Factors determining the level of authorization include the type of equipment installed in the aircraft, the redundancy of that equipment, its operational status, the level of flight crew training, the level of the operator’s FAA authorization, etc. APV: Approach with vertical guidance. VNAV: VNAV stands for “vertical navigation.” Authorization to use VNAV on a conventional nonprecision approach, RNAV approaches, or LNAV/VNAV approaches is found in that operator’s OpsSpecs, AFM, or other FAA approved document. Important: Do not assume that a GPS navigator with VNAV capability will produce glideslope-like vertical guidance. On many common GPS navigators, the VNAV function is only a descent planning and situational awareness tool. Know your equipment! LNAV: LNAV stands for “lateral navigation” LNAV minimums are provided for RNAV systems that do not produce any VNAV information. Because vertical guidance is not provided, the procedure minimum altitude is published as an MDA. These minimums are used in the same manner as conventional nonprecision approach minimums. Other RNAV systems require special approval. LPV: LPV is not an acronym, but you might think of it as “localizer performance with vertical guidance.” The term refers to APV minimums that use Wide Area Augmentation System (WAAS) to provide electronic vertical guidance capability. Important: Your aircraft must have WAAS avionics equipment approved for these approaches in order to fly to LPV minimums. LNAV/VNAV: Minimums listed as LNAV/VNAV are APV minimums used by aircraft with RNAV equipment that provides both lateral and vertical information in the approach environment, including WAAS avionics approved for LNAV/VNAV approaches, certified barometric-VNAV (Baro-VNAV) systems with an IFR approach approved GPS, certified Baro- VNAV systems with an IFR approach approved WAAS system, or approach certified RNP 0.3 systems. Minimums are shown as DAs because the approaches are flown using an electronic glidepath. Other RNAV systems require special approval. List Your Information Sources From the approach charts and the Airport/Facility Directory A/FD, determine whether radar is available. You may also want to know the Minimum Vectoring Altitude for the destination area, to determine if a visual or contact approach is possible. Find out what sources of weather reporting exist at your destination: ATIS, AWOS, ASOS, etc. and be sure that you have the frequencies for each one readily available. Review Personal Minimums Before departing, review your personal minimums and compare them to conditions you expect at departure, while enroute, and at your destination. Take into account how current and proficient you are, your experience level, and your familiarity with the aircraft and its systems. If you are a relatively new instrument pilot, set your minimums high – possibly even VFR or MVFR conditions – until you gain experience in the system, and in the type of aircraft and equipment you will operate. In addition, keep in mind that personal minimums may need to change on any given day. If, for example, you are flying an unfamiliar airplane, or if you are tired from a long day at work, you may not want to attempt low approaches. Make an Escape Plan One of the most important things to do in your preflight planning for IFR flight is to find, and plan, your escape route. Don’t launch your flight without knowing where to find the nearest present, or forecast, VFR weather that is within range of your aircraft. You might also find it helpful to identify a suitable airport for each 20-30 mile segment of your route. The VFR escape plan could also be very useful in a lost comm situation. (Note: It’s a good idea to review lost comm procedures from time to time.)
Instrument Tip: Going visual
It seems that for forever, the advice was to chop the power at the final approach fix and dive for the minimum descent altitude, with the goal of seeing the runway as early as possible, and then starting a descent.
The visual descent point (VDP) is a tool to stop the madness and bring some stability to nonprecision approaches. Missed approach points are often near the end of the runway. This gives you the latitude to drop down to the minimum descent altitude and then drone along until the bitter end. If you don’t see the runway, the decision to start the missed approach is easy. But what if you do see the runway? Now you have to decide if you want to dive down in order to make it. In a slow, draggy airplane, this might not be a problem. But as you step up to bigger and faster airplanes, it’s easy to see how you could skid off the end of the runway in such a scenario.
The VDP is a marker on the approach from which a normal descent and landing can be made, and in certain applications takes away the needs for such a hasty last-minute decision. It generally reflects the intersection of a 3-degree glideslope with the missed approach altitude.
When you arrive at the VDP you have three options:
Ignore it. The VDP isn’t the missed approach point. There’s no requirement that you do anything at the VDP, so you have the option to keep buzzing along until you reach the MAP. Start a descent. The VDP does not give you a clearance to descend below the minimum descent altitude before seeing the runway. It’s not a license to ignore the requirements of FAR 91.175 (the conditions by which you’re allowed to descend below the minimum descent altitude). But, if you’ve already broken out of the clouds and the visibility is good enough that you can see the runway, the VDP is a good point from which to begin the final descent to the runway. Even though it isn’t regulatory, it’s also good to think of the VDP as the absolute initial point of the final descent. As the Aeronautical Information Manual says, “The pilot should not descend below the MDA prior to reaching the VDP.” Go missed. Although we’re trained to continue an approach to the missed approach point, there’s nothing that says we can’t break it off early. Doing so could be the safest course of action. If you think of the VDP not as a point from which a decent can begin, but instead as the primary missed approach point, you’ll never be faced with the choice of whether or not to dive for the runway at the last moment. Rather, when you don’t see the runway at the VDP, begin the missed approach, knowing that you can’t make a normal stabilized approach beyond that point.
Not every nonprecision approach has a VDP. If an obstruction rises into the visual segment of the approach, a VDP won’t be published, for example. In these cases you can mentally create your own VDP by taking the difference between the minimum descent altitude and the touchdown zone elevation and dividing by 300. This will give you a general point at which to begin the descent or go missed, but remember that the absence of the VDP may mean there’s an obstruction to avoid. Also keep in mind that for this calculation you are looking for distance from the end of the runway, not the GPS center point or DME of the airport. Usually these are in the middle of the airport. You may need to subtract this distance from your VDP to make sure you end up with a stabilized approach to the runway and not a phantom marker in the middle of the airport.
With the VDP there’s no longer a reason to dive for the runway at the missed approach point. Especially in instrument conditions, stability is the goal, and a VDP offers just that.
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Visual Descent Point (VDP)
Aviation Glossary :: Visual Descent Point (VDP) Welcome to the Dauntless Aviation Glossary! At Dauntless, our editorial staff maintains the web’s largest unified glossary of aviation terms. This glossary is built from a combination of official, quasi-official, and proprietary sources (including original material that we develop oursselves). Uniquely, we often provide multiple definitions of a given term so that you can find that which best applies to you. In order to maximize your learning efficiency, this glossary (and similar ones for our international users) is incresingly fully integrated into our aviation learning apps, including our FAA written test prep and FAA practical test prep software and apps. If you like this glossary, you’ll love them with their polished learning environments and world’s best and clearest content (please do give them a try.). Visual Descent Point (VDP) Visual Descent Point (VDP)
Terms and Definitions Visual Descent Point (VDP)
Request a Term Visual Descent Point (VDP) Visual Descent Point (VDP): A defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the runway environment is clearly visible to the pilot. source: FAA Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25A) VISUAL DESCENT POINT (VDP): A defined point on the final approach course of a non-precision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the approach threshold of that runway, or approach lights, or other markings identifiable with the approach end of that runway are clearly visible to the pilot. source: ICAO Aviation Chart Glossary
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