GPWS callouts explained: learn what SINK RATE, PULL UP, DON'T SINK, TERRAIN, GLIDESLOPE and other cockpit warnings mean.
GPWS callouts are spoken cockpit alerts generated when an aircraft risks striking terrain, descends too rapidly or approaches the ground in an unsafe configuration. In real-world aviation, phrases such as “SINK RATE”, “DON’T SINK” and “PULL UP” describe different hazards and urgency levels; a warning demands the aircraft-specific escape response.
The basic Ground Proximity Warning System uses radio altitude, vertical speed, airspeed and aircraft-configuration inputs. Enhanced GPWS, usually abbreviated EGPWS or TAWS, adds position data and terrain or obstacle databases, allowing it to predict threats ahead. Our separate explanation covers how GPWS and enhanced GPWS detect terrain risk.
What do the common GPWS callouts mean?
Each GPWS phrase identifies a particular flight-path, terrain or configuration hazard.
| Callout | Meaning | Typical urgency |
|---|---|---|
| SINK RATE | The descent rate is excessive for the aircraft’s height above the ground. It may repeat and escalate to PULL UP if the unsafe trend continues. | Caution |
| WHOOP WHOOP, PULL UP | The system calculates an immediate terrain-collision danger. The “whoop” is an attention-getter, not a separate condition. | Warning requiring an immediate published escape manoeuvre |
| TERRAIN, TERRAIN, CAUTION TERRAIN or TERRAIN AHEAD | Terrain is dangerously close or predicted to conflict with the flight path. Exact wording depends on the installation and whether the alert is predictive. | Caution that can escalate to PULL UP |
| OBSTACLE or OBSTACLE AHEAD | An enhanced system predicts a conflict with an obstacle represented in its database. | Caution or warning, depending on proximity |
| DON’T SINK | The aircraft has lost an unsafe amount of height after take-off or during a go-around. It does not simply mean that the aircraft is descending. | Caution |
| TOO LOW GEAR | The aircraft is close to the ground without the landing gear in the expected landing position. | Configuration alert |
| TOO LOW FLAPS | The aircraft is close to the ground without the expected landing-flap configuration. | Configuration alert |
| TOO LOW TERRAIN | Terrain clearance is inadequate for the aircraft’s height, speed or configuration, even if no obstacle is directly ahead. | Caution |
| GLIDESLOPE | The aircraft has deviated significantly below the ILS glideslope during the approach. | Approach-deviation caution |
| BANK ANGLE | The bank exceeds a height-dependent limit, particularly close to the ground. | Advisory or caution |
| WINDSHEAR | The fitted windshear system has detected a severe loss or change of wind energy. This may be provided through an EGPWS function or another aircraft system. | Warning requiring the dedicated windshear escape procedure |
The exact distinction between caution, advisory and warning varies by equipment and operator configuration. We explain the urgency and interpretation of PULL UP and GLIDESLOPE separately, along with why DON’T SINK sounds after take-off or a go-around.
Are “50, 40, 30, 20, 10” GPWS warnings?
Numeric height announcements are radio-altitude callouts, not warnings that terrain impact is predicted.
They are often played by the same EGPWS computer, which is why simmers commonly call every automated landing voice a GPWS callout. “MINIMUMS” marks a selected decision altitude or height, while the Airbus “RETARD” prompt is a flare thrust reminder. Our guide to flare-height, minimums and RETARD announcements explains those landing cues in context.
TCAS commands such as “CLIMB” and “DESCEND”, stall warnings, overspeed warnings and autopilot-disconnect sounds also come from other systems. Sharing a cockpit speaker does not make them GPWS alerts.
What should pilots do when GPWS sounds?
Pilots respond according to the alert level, aircraft flight manual and operator procedure rather than treating every callout alike.
- PULL UP or a terrain warning: execute the published terrain-escape manoeuvre immediately unless the aircraft-specific procedure states otherwise. Troubleshooting comes later.
- WINDSHEAR: use the dedicated windshear escape procedure; it may differ from the terrain-avoidance manoeuvre.
- A caution such as SINK RATE: correct the flight path promptly and go around if a safe, stabilised approach cannot be restored.
- A configuration callout: verify the gear and flap state. Do not continue an approach outside the aircraft’s checklist and stabilisation criteria.
Nuisance alerts can occur during unusually steep approaches, over sharply rising terrain, after a sensor fault or because of terrain-database limitations. Pilots still treat an unexpected warning as genuine until safety is assured. GPWS modes should only be inhibited where an approved procedure specifically permits it.
Why do GPWS callouts vary between aircraft and simulators?
Callouts vary because aircraft can have classic GPWS, enhanced terrain-awareness equipment, optional voice sets and operator-selected alert configurations.
A simulator aircraft may reproduce every terrain mode, provide only radio-height announcements or merely play sounds at fixed altitudes. A mistake we see constantly is assuming that hearing “fifty” proves the add-on has working terrain protection. Without the relevant sensor logic, alert envelopes and terrain data, it is an audio callout system rather than a complete EGPWS simulation.