Learn why an aircraft sinks rapidly on final approach and how airspeed, power, flap, wind and stabilised-approach decisions prevent it.
An aircraft sinks rapidly on final when it has too little energy for its weight, drag and descent path, usually because airspeed or power is low, drag was not anticipated, or wind changed. Prevent it by flying the published approach speed, trimming properly, managing power early and going around whenever the approach becomes unstable.
For Aviation & Real-World Flying, the first distinction is between a genuinely unsafe sink and a normal vertical speed that merely looks high. On a three-degree glidepath, the approximate descent rate in feet per minute is groundspeed in knots × 5. At 140 knots groundspeed, about 700 feet per minute is normal; a tailwind raises the required descent rate for the same glide angle.
In an actual aircraft, the POH or AFM, checklist, instructor guidance and operator procedures take precedence over generic technique.
What causes excessive sink on final approach?
Excessive sink usually comes from low energy, an uncorrected increase in drag or a wind change close to the ground.
- Low airspeed and excessive angle of attack: As the aircraft slows, induced drag rises. Pulling the nose up without adding enough power can make the sink worse and may lead to a stall.
- Too little power: An aircraft can hold the correct-looking attitude while settling below the desired path. Turbine engines also need time to spool up, so a late thrust increase may not arrest the descent quickly.
- Gear or flap deployment: Configuration changes alter lift, drag and pitching moment. The exact response is type-specific, but failing to anticipate the net drag increase commonly produces a sink after an initial balloon or pitch change.
- Steep bank on base or final: Banking increases the lift required to maintain the flight path. A tightening turn close to the ground can produce rapid sink, especially if the pilot tries to hold altitude with back pressure.
- Wind gradient, downdraught or windshear: A decreasing headwind can cause an abrupt loss of indicated airspeed and lift. A tailwind also increases groundspeed and therefore the vertical speed needed to remain on the glidepath.
- Incorrect speed or loading data: A memorised speed may be unsuitable for the actual weight, configuration or aircraft variant. Ice or other contamination can also increase drag and stall speed.
The mistake we see most often is trying to cure every sink with extra back pressure. That converts airspeed into a brief reduction in descent, followed by an even lower-energy condition.
How can I identify the cause?
The airspeed trend, pitch attitude, aiming point and timing of the sink usually reveal what changed.
| What you observe | Likely cause | Correct response |
|---|---|---|
| Falling airspeed, high nose attitude or stall warning | Excessive angle of attack and low energy | Apply approved power, reduce angle of attack as required and go around if the approach is not immediately stabilised |
| Airspeed near target, but the aiming point rises or the PAPI shows more red | Aircraft descending below the intended path | Make an early, coordinated power and pitch correction; do not wait until the threshold |
| Sink begins immediately after gear or flap extension | Configuration drag was not anticipated | Use the expected power and pitch change, then retrim |
| Rapid airspeed fluctuations with an abrupt vertical-speed change | Gust, downdraught or windshear | Go around or use the aircraft's published windshear escape procedure |
| High indicated descent rate but stable speed and glidepath | High groundspeed or a steeper published approach | Compare the rate with groundspeed and the published glide angle rather than chasing the vertical-speed indicator |
| Sink starts after autopilot disconnection | Out-of-trim aircraft or an unnoticed automation mode | Hold the required attitude, retrim and reassess whether the approach remains stabilised |
How do I prevent rapid sink on final?
A stabilised approach prevents most rapid-sink events by putting the aircraft on speed, on path, correctly configured and properly trimmed before reaching the runway environment.
- Calculate the correct target speed. Use the approved value for the aircraft, weight, configuration and conditions. Apply only the wind correction specified by the handbook or operating procedure. Our guide to managing approach and landing speed explains how to avoid both low-energy and excessively fast approaches.
- Configure on schedule. Extend gear and flap early enough to observe the resulting pitch and drag changes. Avoid creating a large configuration change close to the ground.
- Trim for the target condition. The aircraft should not require heavy continuous pressure to maintain approach speed. Poor trim encourages over-control and becomes particularly obvious after disconnecting the autopilot.
- Coordinate pitch and power. In many light aircraft, pitch is treated as the primary control for airspeed and power as the primary control for glidepath once established. That is a prioritisation aid, not an absolute rule: both controls interact, and transport aircraft procedures may require a different emphasis.
- Watch trends rather than single readings. Cross-check airspeed, power, attitude, aiming-point movement and glidepath indications. A rising aiming point means the projected touchdown point is moving towards the aircraft and the approach is becoming short.
- Use the stabilised-approach gate. Go around if speed, sink rate, configuration, alignment or power is outside the approved tolerance at the specified gate. The exact heights and limits vary by aircraft and operator; inventing personal limits is no substitute for the applicable procedure.
What should I do if the sink rate suddenly increases?
An unexpected, sustained sink close to the ground should normally trigger a go-around unless a small correction restores a fully stabilised approach without delay.
- Apply power promptly as the aircraft procedure requires while controlling pitch to maintain the correct speed or angle of attack.
- Do not pull back aggressively to arrest the descent. If a stall warning appears, reduce angle of attack and follow the approved recovery; our angle-of-attack and stall-prevention explanation covers why pitch alone cannot replace missing energy.
- Do not retract flap or gear abruptly. Removing flap can cause an immediate loss of lift, and normal go-around configuration changes should occur only in the prescribed sequence.
- For a windshear warning or severe performance loss, use the published windshear escape manoeuvre. It may differ from an ordinary go-around in thrust, pitch guidance and configuration handling.
Why does the aircraft sink just before touchdown?
A late sink usually comes from flaring too high, reducing power too early, raising the nose excessively or losing headwind near the threshold.
Cross the threshold at the correct speed, shift to the aircraft's approved flare sight picture and reduce power in the manner specified for that type. Do not stretch the flare with increasing back pressure after the energy has gone. Ground effect itself does not normally make an aircraft drop; it reduces induced drag. For simulator-specific flare work, our techniques for curing hard or floaty touchdowns address power reduction, trim and excessive pitch input.
What if rapid sink happens only in a flight simulator?
Simulator-only sink problems usually point to incorrect aircraft data, control assignments, automation modes or weather rather than a different aerodynamic principle.
- Confirm the loaded weight and centre of gravity, then calculate the approach speed from the model's checklist, EFB or performance system.
- Check that the throttle axis reaches the commanded range and that no duplicate bindings operate throttle, spoilers, flaps or pitch trim.
- Read the autopilot and autothrottle mode annunciations. A selected vertical-speed mode, missed glidepath capture or disconnected autothrottle can produce a perfectly commanded but unsafe descent.
- Test the same approach in calm, clear conditions without time acceleration. This separates technique and control setup from gusts, icing, failures or weather modelling.
In Microsoft Flight Simulator 2020 or 2024, following a consistent stable MSFS landing sequence makes it much easier to identify the exact point at which speed, configuration or glidepath begins to depart from target.