What is a Visual Descent Point (VDP) on a non-precision approach?

A Visual Descent Point, or VDP, is a defined point on the final approach course of a non-precision approach from which a normal, stabilized descent from the Minimum Descent Altitude (MDA) to the runway touchdown zone can be initiated. It is depicted on approach charts as a "V" symbol and is intended to help pilots avoid both Controlled Flight Into Terrain (CFIT) and unstabilized approaches. If the required visual references are not established by the VDP, pilots should not begin descending below the MDA. The VDP concept is discussed in the FAA's Instrument Flying Handbook as a key tool for executing safe non-precision approaches.

How do you calculate a Visual Descent Point when it is not published on an approach chart?

When a VDP is not published, pilots can calculate an approximate point by dividing the height above touchdown (HAT) — the MDA minus the touchdown zone elevation — by 300, which gives the distance in nautical miles from the runway threshold at which a standard 3-degree descent would begin. For example, if the HAT is 300 feet, the VDP would be approximately 1 nautical mile from the threshold. This calculation assumes a standard 300-foot-per-nautical-mile descent gradient, consistent with guidance in the FAA's Instrument Flying Handbook. Applying this technique supports a stabilized descent profile even when the VDP is not charted.

What's the difference between an MDA and a VDP on a non-precision approach?

The Minimum Descent Altitude (MDA) is the lowest altitude a pilot may descend to during a non-precision approach without having the required visual references to continue to a landing, as defined in 14 CFR Part 97 and the AIM. The Visual Descent Point (VDP), by contrast, is a specific lateral position along the final approach course — not an altitude — that identifies the optimal place to begin a descent from the MDA to the runway. Reaching the MDA before the VDP means the pilot should level off and fly at the MDA until the VDP is reached or visual references are acquired. Together, the MDA and VDP define both the vertical and horizontal boundaries of a safe non-precision approach profile.

Visual Descent Point Calculation and Use

On a non-precision instrument approach, pilots fly level at the Minimum Descent Altitude (MDA) until they either acquire the required visual references or reach the Missed Approach Point (MAP). That sounds simple enough — but there's a hidden danger: descending too late from the MDA can set up an uncomfortably steep, potentially unsafe dive toward the runway. The Visual Descent Point (VDP) solves this problem by marking the optimal location on the final approach course from which a normal, stabilized descent from the MDA will deliver the aircraft to the runway touchdown zone. Think of it as the non-precision approach's equivalent of the glideslope intercept point on an ILS.

The VDP is a defined point on the final approach segment of a non-precision approach from which a normal descent — using standard glide path geometry — may be made from the MDA to the runway threshold. When it appears on an approach chart, it is depicted as a small bold "V" symbol on the profile view. Understanding not just what the VDP is, but how it is calculated, when it may be absent, and how to use it operationally, is essential knowledge for the instrument rating knowledge test and for safe real-world flying.

How the VDP Works

Every non-precision approach has a final approach course at a specific angle relative to the runway. When you reach the MDA and look out at the runway, you need enough distance remaining to descend at a normal approach angle — roughly 3 degrees, which corresponds to approximately a 300-foot loss of altitude per nautical mile — without resorting to an extreme nose-low attitude or a dangerously high sink rate. The VDP is computed so that a standard 3-degree descent from that point, starting at the MDA, will intersect the runway at the threshold (or touchdown zone).

The FAA publishes VDPs on approach charts when the geometry of the approach allows it. When a VDP is depicted, it tells you: if you have the runway environment in sight by the time you reach this point, you can leave the MDA and fly a normal descent angle. If you do not have the required visual references at the VDP, it is a strong signal to prepare for a missed approach, because descending after the VDP means you will have to increase your descent rate beyond what is considered stabilized and safe.

Calculating the VDP

The VDP can be calculated manually when it is not published on the approach chart, or when you want to verify the published value. The standard formula is straightforward:

VDP Distance from the MAP = Height Above Touchdown Zone Elevation (HAT) ÷ 300

The result is in nautical miles. The HAT is simply the MDA expressed in feet above the touchdown zone elevation (TDZE), which is printed directly on the approach chart alongside the MDA. Divide that HAT value by 300 — the feet-per-nautical-mile descent rate for a 3-degree glide path — and you get how many nautical miles before the MAP the VDP lies.

Worked example: Suppose an approach has an MDA of 1,200 feet MSL and a TDZE of 600 feet MSL. The HAT is therefore 1,200 − 600 = 600 feet. Dividing 600 by 300 gives 2.0 nautical miles. So the VDP is located 2.0 NM before the MAP. If the MAP is at a DME fix, you would subtract 2.0 NM from the MAP DME to find the VDP location. If time-based, you convert that distance to time at your groundspeed.

This formula uses 300 feet per nautical mile as the standard conversion because a 3-degree glide path yields approximately 318 feet per nautical mile; 300 is the standard FAA approximation used in VDP calculations, making the math clean and slightly conservative.

When the VDP Is Not Published

Not every non-precision approach will have a published VDP. The FAA will omit the VDP from an approach chart when obstacles or terrain in the visual segment of the approach would be penetrated by a normal 3-degree descent from the MDA. In other words, if a straight-in, standard-angle descent from the MDA would fly through or uncomfortably close to obstacle surfaces, publishing a VDP could give pilots a false sense of security. In this situation, the approach does not depict a VDP, and pilots should recognize that extra caution is warranted in the visual segment.

When the VDP is absent, pilots must carefully manage their descent from the MDA. The absence of a VDP is itself a red flag: it signals that the visual segment may have obstacles, that the runway environment requires an unusual sight picture, or that the approach geometry does not allow a normal descent angle. In practice, if you cannot calculate a safe descent point, consider the missed approach point to be the final decision gate and be alert for the need for an early missed approach.

Why the VDP Matters for Safety

The VDP directly addresses one of the most serious threats on non-precision approaches: Controlled Flight Into Terrain (CFIT). CFIT accidents on non-precision approaches often involve an aircraft that is at or near the MDA but has not yet reached the runway and descends prematurely or too steeply. The VDP provides a structured, geometry-based constraint on when it is actually safe to begin descending.

A secondary safety benefit is that the VDP promotes stabilized approaches. Flying beyond the VDP before descending forces pilots into high sink rates close to the ground — a classic setup for a hard landing, runway overrun, or loss of control. The FAA's risk management guidance emphasizes that an unstabilized approach is a significant risk factor; the VDP prevents this by ensuring the descent angle is achievable at normal power settings and pitch attitudes.

Operationally, treating the VDP like a glideslope intercept reinforces disciplined instrument flying habits. A good technique is to brief the VDP during approach preparation and cross-check DME or timing against it on final. If you are not visual at the VDP, mentally commit to the missed approach procedure and execute it crisply at the MAP if visual contact has not been established.

Key Numbers and Rules

VDP Formula: HAT (feet) ÷ 300 = VDP distance (nautical miles) before the MAP.
Standard glide path angle: 3 degrees, equating to approximately 300 feet per nautical mile descent (FAA standard approximation).
HAT: MDA minus the Touchdown Zone Elevation; always printed on the approach chart in parentheses next to the MDA value.
VDP symbol on chart: A bold letter "V" on the profile view of an approach chart — not depicted in the plan view.
No VDP published: Means a normal descent from MDA would penetrate the obstacle identification surface in the visual segment; exercise extra caution.
Descent below MDA: Permitted only when the pilot has the required visual references, the aircraft is in a position to land using a normal rate of descent, and flight visibility is at or above the published minimum — per 14 CFR Part 91.175.
Missed approach: Must be executed no later than the MAP if visual references are not established; the VDP does not replace the MAP as the legal missed approach trigger.

Common Test Traps

Confusing VDP with MAP: The VDP is where you should begin descending if visual — the MAP is where you must execute a missed approach if not visual. They are different points, and descending at the MAP (not the VDP) is always too late for a stabilized approach.
Using MSL instead of HAT: The formula requires Height Above Touchdown (HAT) — the MDA relative to the TDZE — not the MDA in feet MSL. Using the MSL value produces a completely wrong answer.
Assuming all approaches have a VDP: The FAA omits VDPs when the visual segment contains obstacles that would be penetrated by a normal descent. The absence of a VDP is meaningful information, not an omission to ignore.
Thinking the VDP authorizes descent: Reaching the VDP does not legally authorize descent below the MDA. 14 CFR 91.175 conditions must be met — you must have the required visual references and appropriate flight visibility. The VDP is a geometry checkpoint, not a legal clearance to descend.
Misidentifying the VDP symbol: The FAA knowledge test occasionally asks about chart symbology. The VDP is shown in the profile (side-view) section of the chart as a bold "V," not in the plan view. Do not confuse it with other waypoint or fix symbols.

Mastering the VDP concept — its calculation, its chart depiction, its absence, and its proper use — is a mark of genuine instrument flying competency. It bridges the gap between the mechanical altitude and distance numbers on a chart and the real-world task of touching down safely in reduced visibility conditions. Brief it, calculate it, and respect it on every non-precision approach you fly.