If you have ever driven along Avenida dos Bandeirantes in São Paulo, you have probably noticed a large blue metallic structure sitting at the end of the runway at SBSP, São Paulo Congonhas Airport. Most people have no idea what it is. Some think it is part of the airport's lighting system. Others assume it is a construction site that never quite finished. In reality, it is one of the most important safety installations at any busy urban airport, and understanding how it works tells you a lot about how seriously aviation takes runway safety.
What Is EMAS and Why Does It Matter?
EMAS, which stands for Engineered Materials Arresting System, is a runway safety area technology designed to stop an aircraft that overruns the end of a runway. The concept is straightforward: if an aircraft cannot stop before the pavement runs out, something at the end of that pavement needs to absorb the kinetic energy and bring it to a halt without killing anyone on board.
Think of the gravel escape ramps you see on steep mountain roads. Trucks that lose their brakes drive into a bed of deep gravel, which slows them down through resistance. EMAS works on the same principle, but instead of loose gravel, it uses specially engineered blocks made from a highly porous, crushable concrete-like material. When an aircraft rolls into the EMAS bed, the weight and forward momentum of the aircraft causes the blocks to crush and break apart, absorbing energy in the process.
The system is recognized by both the FAA (Federal Aviation Administration) and ICAO (International Civil Aviation Organization) as an acceptable means of providing a runway end safety area (RESA) where physical space is limited. At many urban airports around the world, there simply is not enough flat land beyond the runway to install a conventional RESA of the recommended length. EMAS fills that gap.
Why Congonhas Needed This Technology
Congonhas is one of the busiest and most operationally complex airports in South America. Located inside the city of São Paulo, it handles around 44 aircraft movements per hour, roughly 540 per day, and is surrounded by densely populated neighborhoods and major highways. The airport operates on a single runway, designated 17/35, and runway 17 points almost directly toward Avenida dos Bandeirantes, one of the city's main expressways.
That geography creates an obvious problem. If an aircraft were to overrun runway 17 without being stopped, it could travel beyond the airport perimeter and onto a public road. The installation of EMAS on both runway ends, 17 and 35, addresses this risk directly. The system was constructed in late 2021 and officially inaugurated in March 2022. Since then, it has not been needed, which is exactly the right outcome.
The EMAS bed at Congonhas is designed to stop an aircraft traveling at approximately 130 km/h. That covers the speed range of most runway excursion scenarios, where the aircraft has already attempted to brake but has not been able to stop within the available runway length.
How the Structure Is Built
From the outside, the EMAS installation at Congonhas looks like a solid platform covered in a smooth protective surface. That surface is not the arresting material itself. It is a protective top layer designed to keep the crushable blocks underneath intact during normal airport operations.
This matters because the runway threshold area is used daily for takeoff rolls. If the crushable blocks were exposed, the jet blast and wheel traffic from departing aircraft would gradually damage them. The protective cap keeps the system ready for use while shielding it from routine wear.
Underneath that cap are the crushable cellular cement blocks. These are porous, lightweight, and engineered to fracture under the weight of an aircraft. The blocks are arranged so that the aircraft sinks progressively into the material rather than hitting a sudden hard stop, which would itself cause injuries. The system is designed to engage the aircraft's landing gear and tires, not the fuselage or the belly of the plane. The goal is to stop the aircraft while preserving its structural integrity so that evacuation can happen safely.
Pro tip: EMAS does not damage the aircraft's main landing gear beyond what you would expect from a hard off-runway contact. Real-world activations at other airports around the world have confirmed that passengers and crew have been able to evacuate normally after an EMAS engagement.
The Offset Area and Emergency Access
One design feature that is easy to overlook is the offset, the area of solid pavement that runs alongside the EMAS bed. The EMAS material itself matches the width of the runway, which at Congonhas is 45 meters. But emergency vehicles cannot drive onto the crushable surface. If fire trucks or rescue crews needed to reach an aircraft stopped in the EMAS bed, driving over the blocks would cause them to sink in just like the aircraft.
The offset solves this. It provides a firm, stable surface wide enough for fire and rescue vehicles to drive alongside the EMAS bed and reach the aircraft from either side. There is also a hard surface at the far end of the bed for the same reason. Once an aircraft is stopped, the priority becomes getting people out, and that requires vehicle access from multiple angles.
The concrete border around the EMAS area also gives evacuating passengers a firm surface to step onto after exiting through emergency slides. This is not a detail that gets much attention in general coverage of runway safety, but it is part of a carefully thought-out system where every component serves a specific operational purpose.
Approach Lighting and the EMAS Structure
Installing the EMAS platform at the end of runway 17 required a creative solution for the ALS (Approach Lighting System). The approach lights extend outward from the runway threshold, helping pilots establish visual reference during instrument approaches, low-visibility conditions, and night operations. At Congonhas, some of the ALS towers that were previously freestanding had to be incorporated into the EMAS structure itself.
The result is that the lighting infrastructure now sits partially beneath the platform, with the light heads emerging through the surface at the correct heights and angles. The strobing sequenced flashers, which pulse from the outer approach lights toward the threshold to guide pilots visually, continue to function exactly as they did before. The system remains fully operational, and pilots flying the approach into runway 17 see an uninterrupted lighting sequence from the outer approach to the threshold.
This integration required careful engineering coordination, but it preserved the full function of both systems without compromise.
Understanding the Displaced Threshold
Adjacent to the EMAS installation at Congonhas, there is a section of runway marked with large arrows pointing in the direction of landing. This is the displaced threshold, and it is a common feature at airports where obstacles, lighting systems, or other constraints require that the usable landing area begin further down the runway than the physical runway end.
A displaced threshold means that the marked starting point for landings is set back from the beginning of the paved surface. Pilots land beyond the arrows. The paved area before the displaced threshold is still usable for takeoff rolls and for landing rollout after passing through. It is not a prohibited area. It is just not the starting point for touching down on arrival.
At Congonhas, the displaced threshold on runway 17 exists partly because of the PAPI (Precision Approach Path Indicator) installation and the approach lighting geometry. Pilots departing on runway 17 can use the full length of pavement from the very start, giving them the maximum possible takeoff distance. Arriving aircraft begin their landing roll from the displaced threshold position, ensuring obstacle clearance on the approach path.
The EMAS area, by contrast, is entirely non-transitional under normal circumstances. It is marked with yellow chevron symbols, the universal marking for surfaces that aircraft should not enter except in an emergency. The chevron pattern is immediately recognizable to any trained pilot and indicates that the surface beyond is not designed for normal aircraft operations.
Runway Excursions: A Persistent Safety Challenge
Runway excursions, events where an aircraft goes off the side or end of a runway, remain one of the most common categories of serious aviation accidents globally. The Flight Safety Foundation and ICAO have both identified runway excursions as a priority safety concern, particularly at airports with shorter runways, challenging approaches, or limited runway end safety areas.
The 2007 accident at Congonhas involving a TAM Airlines aircraft remains a defining moment in Brazilian aviation safety history. That event involved a lateral excursion under specific conditions that included wet runway contamination and operational factors. Whether EMAS would have altered the outcome of that specific accident is impossible to say with certainty, because excursion direction and speed matter enormously. What is clear is that the installation of EMAS, combined with runway surface improvements and drainage upgrades at Congonhas, represents a substantial safety investment aimed at reducing the risk of a similar event.
Congonhas has also invested in pavement drainage technology to reduce the risk of aquaplaning, where a thin film of water lifts the tires off the pavement surface and dramatically reduces braking effectiveness. Together, these systems address the two main physical factors that contribute to runway overrun accidents: insufficient friction and insufficient stopping distance.
Did you know? EMAS installations have been successfully activated at several airports in the United States, stopping aircraft that would otherwise have gone beyond the runway end. In each case, the aircraft remained intact and all occupants survived.
Night Operations and Access Restrictions
Congonhas operates under a nighttime curfew. Between 11:00 PM and 6:00 AM, commercial landing and takeoff operations are suspended. This restriction exists because the airport is surrounded by a dense urban area, and nighttime jet noise would affect hundreds of thousands of residents. The curfew is a condition of the airport's operating license and has been in place for many years.
This curfew window is actually useful for maintenance, inspections, and access to areas like the EMAS installation that would otherwise be too close to active runway operations to access safely. Airport infrastructure that sits within the runway strip or at the runway ends can only be properly inspected, photographed, or maintained during periods when the runway is not in use.
Key Takeaways
- EMAS stands for Engineered Materials Arresting System, a runway end safety technology that uses crushable cellular cement blocks to stop overrunning aircraft.
- The system at SBSP Congonhas was installed on both ends of runway 17/35 and inaugurated in March 2022.
- The protective surface cap over the EMAS blocks keeps the system intact during normal operations while allowing aircraft to break through in an emergency.
- The offset area around the EMAS bed provides firm ground for emergency vehicle access and passenger evacuation.
- Approach lighting (ALS) was integrated into the EMAS structure without loss of function.
- The displaced threshold near the EMAS area allows full use of the pavement for takeoff while setting back the landing reference point for arriving aircraft.
- EMAS is recognized by ICAO and the FAA as an approved means of providing a runway end safety area where space is limited.
- The system is designed to stop an aircraft traveling at around 130 km/h while preserving the aircraft's structure and enabling safe evacuation.
Explore Airport Safety Infrastructure on Data Sky Center
Understanding the infrastructure at airports you fly into or out of is part of good airmanship and professional situational awareness. Knowing that SBSP has EMAS installations, a displaced threshold, and nighttime curfew restrictions could matter during your preflight planning, especially if you are operating into a shorter runway or under marginal weather conditions.
On Data Sky Center, you can search airport details, review runway data, check NOTAMs, and explore operational characteristics for airports across Brazil and around the world. Whether you are planning a domestic hop or a complex international routing, having accurate airport information at hand makes every flight safer and more predictable.
