How do I fly a 3-degree descent path for landing?

To fly a standard 3-degree descent path for landing, cross each nautical mile from the threshold about 318 feet above threshold elevation, plus the planned threshold-crossing height. Set an initial descent rate of groundspeed × 5 in feet per minute, then use PAPI, VASI or glidepath guidance to make small corrections.

For Aviation & Real-World Flying, three degrees is a conventional approach angle, not a rule for every runway. Always use the published approach angle, aircraft flight manual and applicable operating procedure when they specify something different.

What altitude should I be at on a 3-degree approach?

A 3-degree path descends approximately 318 feet per nautical mile. If the intended threshold-crossing height is 50 feet, use:

target altitude MSL = threshold elevation + 50 ft + (distance to threshold in NM × 318)

These figures assume a 50-foot threshold-crossing height. Use the charted TCH where one is published. Check what your distance source measures as well: airport-reference-point distance, displaced-threshold distance and DME from an offset antenna are not necessarily distance to the landing threshold.

What vertical speed gives a 3-degree descent?

The accurate calculation is approximately groundspeed × 5.3 in feet per minute. The familiar groundspeed-times-five rule is easier to perform mentally and provides a useful starting setting.

Use groundspeed, not indicated airspeed. A headwind reduces the required descent rate, while a tailwind increases it. Recalculate after a significant speed change rather than holding one vertical speed all the way down.

How do I fly the path step by step?

1. Become stable before descending. Establish the correct final-approach track, landing configuration and target speed early enough that configuration changes do not destabilise the path.
2. Identify the correct guidance. Use the published ILS or RNAV glidepath, PAPI or VASI where available. Without vertical guidance, use altitude-versus-distance checks and a stable visual aiming point.
3. Set an initial descent rate. Multiply groundspeed by 5.3, or by 5 for a quick estimate, and trim the aircraft so that speed and attitude settle.
4. Cross-check the result. Compare altitude at each distance checkpoint and monitor the visual or electronic path. Vertical speed is an initial prediction; the glidepath indication is the feedback.
5. Correct gradually. If high, reduce power as appropriate and permit a modest increase in descent rate without gaining excess speed. If low, add power and shallow the descent while protecting approach speed.
6. Transition to the flare. The 3-degree line guides the approach, but it is not flown through touchdown. Use the aircraft-specific flare and landing technique near the runway.

In many light aircraft, modest power changes are the easiest way to adjust the path while coordinated pitch changes maintain speed. Jets and automated flight-control systems may use different pitch-and-thrust logic, so follow the aircraft procedure rather than treating “pitch for speed, power for path” as an absolute law.

How can I tell if I am above or below the glidepath?

A PAPI normally shows two white and two red lights when the pilot's eye is on its designed path. More white means high; more red means low. A VASI normally shows red over white on path.

On an ILS, keep the glideslope indication centred and make small, measured corrections. Our explanation of how ILS vertical guidance shows path deviation covers interception and why chasing the indicator creates oscillations.

During a visual approach, the correct aiming point remains nearly stationary in the windscreen. If it moves upward, the aircraft is tending to undershoot; if it moves downward, the aircraft is tending to overshoot. See our guidance on selecting and holding a runway aiming point for the sight picture behind this technique.

A 50-foot threshold-crossing height on a 3-degree path geometrically projects to a point roughly 1,000 feet beyond the threshold. That does not mean every aircraft should touch down exactly there: cockpit eye height, flare technique and aircraft size affect the actual touchdown point. Large aircraft must also respect any PAPI eye-to-wheel-height limitations.

What causes an unstable 3-degree approach?

• Using airspeed instead of groundspeed: this produces the wrong descent rate whenever there is significant wind.
• Holding a fixed vertical speed: changing wind, speed or configuration changes the rate needed to remain on the path.
• Chasing the PAPI or glideslope: abrupt pitch and power inputs lead to alternating high and low deviations.
• Ignoring runway elevation: altitude checks must be based on threshold elevation and the correct altimeter setting.
• Measuring from the wrong point: an airport icon or DME station may not be located at the landing threshold.
• Forcing three degrees onto every approach: some runways use a different published angle because of terrain, obstacles or local procedure.
• Configuring late: flap, gear and speed changes alter drag and pitch, often creating a large path deviation close to the runway.

When should I stop correcting and go around?

Go around when the approach is not stabilised by the applicable decision gate, or when recovering the path would require large pitch, power, bank or descent-rate changes. Many operators use gates around 1,000 feet above touchdown in instrument conditions and 500 feet in visual conditions, but the controlling aircraft or operator procedure takes precedence.

A late dive from above the path, or pulling up from below while allowing speed to decay, is not a valid correction. In a simulator, use the same go-around discipline: it prevents poor techniques from becoming habits and gives a clearer indication of whether the original approach planning worked.