Learn what an airport EMAS is, how its crushable bed stops runway overruns, where it is installed, and how it differs from arresting cables.
An engineered materials arresting system (EMAS) is a bed of crushable, high-energy-absorbing material installed beyond a runway end. If an aircraft overruns, its landing-gear wheels sink into and crush the material, creating controlled drag that slows the aircraft where there is not enough room for a full runway safety area.
In aviation and real-world flying, EMAS is a passive, last-resort safety installation. It is not extra runway, and neither the pilot nor air traffic control activates it.
How does airport EMAS work?
EMAS slows an aircraft by converting its kinetic energy into the work of crushing a calibrated, low-strength material. The wheels sink progressively into the bed, and the resulting resistance decelerates the aircraft without requiring a tailhook or other special equipment.
Many installations use manufactured blocks of cellular cementitious material beneath a protective, weather-resistant surface. The precise material, bed depth and construction vary. Unlike loose gravel or ordinary soft ground, an approved EMAS bed is engineered to produce predictable resistance.
Each installation is designed around factors such as the available overrun distance, expected aircraft types, landing-gear geometry, aircraft mass and entry speed. It cannot guarantee a stop in every accident: an aircraft may miss the bed, cross it while airborne or enter outside its design assumptions.
Where is EMAS installed at an airport?
An EMAS bed sits beyond the physical runway end, generally centred on the extended centreline. It is most useful where buildings, roads, water, steep terrain or airport boundaries prevent construction of a full-sized runway safety area.
There may be a setback or blast-resistant area between the runway and the crushable section. The bed is not included as usable runway, and pilots must calculate take-off and landing performance without crediting it as stopping distance.
Published airport information may identify the installation, but markings and diagram presentation differ between authorities. To establish exactly where the runway ends and adjoining areas begin, follow the method in our guide to interpreting airport diagrams before taxiing, then confirm EMAS from the airport's operational information rather than colour or appearance alone.
How is EMAS different from a stopway or arresting cable?
EMAS is a sacrificial crushable bed for wheeled aircraft; stopways, blast pads and arresting cables have different construction and operational purposes.
| Installation | Purpose | How it affects an aircraft |
|---|---|---|
| EMAS | Reduce the consequences of a runway overrun | Crushes beneath the landing gear and creates drag |
| Runway safety area | Provide a clear, graded area around the runway | Reduces hazards but may not actively stop the aircraft |
| Stopway | Provide an area for stopping after a rejected take-off | May contribute to declared accelerate-stop distance where officially designated |
| Blast pad | Protect the ground from jet blast | Is not intended for normal aircraft operation or credited stopping distance |
| Arresting cable | Stop suitably equipped aircraft, principally military types | Engages an aircraft's tailhook rather than crushing beneath its wheels |
That cable distinction matters in simulators as well. The Choctaw NOLF naval training-field scenery for FSX and P3D provides the military-airfield context associated with hook-and-cable arrestment; it should not be confused with an EMAS bed at a runway end.
What should a pilot do if an overrun into EMAS is unavoidable?
Pilots should never plan to use EMAS, but if an overrun becomes unavoidable they should remain aligned and follow the aircraft's approved rejected-take-off or landing-overrun procedures.
- Use the available wheel braking, aerodynamic braking and reverse thrust as permitted by the aircraft procedure.
- Maintain directional control and enter the bed as straight as possible; do not swerve around it towards obstacles or unsuitable ground.
- After stopping, carry out the appropriate shutdown or evacuation procedure and follow instructions from air traffic control and emergency services.
- Do not attempt to taxi out of the bed. Even a low-speed entry can embed the wheels and cause additional damage.
EMAS primarily addresses straight-ahead overruns. It offers much less protection during a lateral runway excursion or when the landing gear does not remain in contact with the bed.
Does EMAS damage the aircraft?
EMAS is designed to reduce injury and aircraft damage, not guarantee a damage-free stop. The bed is deliberately sacrificial, and crushed sections must be repaired or replaced after an engagement.
The aircraft will require inspection of its tyres, landing gear, lower fuselage and engines. Recovery may require temporary ramps, specialised towing equipment or lifting because ordinary taxi power could dig the wheels deeper or draw debris towards the engines.
Is EMAS modelled in flight simulators?
In most flight simulators, an EMAS bed may be visual scenery only; realistic stopping behaviour is not guaranteed. Microsoft Flight Simulator, FSX, Prepar3D and X-Plane scenery can display the blocks or runway-end markings while assigning the area generic concrete, asphalt, grass or rough-ground physics.
Some detailed add-ons apply custom surface resistance, but visible EMAS does not prove that it functions. Airport scenery from our freeware aircraft and scenery library can improve runway-end detail, though each package's documentation should be checked for any claim of functional arresting behaviour.