What is an Arresting System?

Arresting System – Equipment for Emergency Aircraft Stopping

An arresting system, also known as aircraft arresting gear, is a critical element of airport safety. These systems are engineered to safely and rapidly decelerate aircraft that overrun a runway, abort takeoff, or experience emergencies, preventing them from breaching runway boundaries and reducing risks to passengers, crew, and infrastructure. Arresting gear is typically installed at or beyond runway ends, or in specific runway locations, especially where standard Runway End Safety Areas (RESA) are not possible due to space, terrain, or operational constraints.

Purpose and Significance

Primary Purpose:
Arresting systems are designed to stop aircraft that cannot halt using standard runway length, especially in emergencies. They are crucial where RESA is insufficient, such as urban, coastal, or mountainous airports with limited expansion possibilities. By absorbing or redirecting kinetic energy, these systems prevent catastrophic accidents and minimize damage.

Operational Relevance:

• Civil Airports: EMAS is commonly used at space-constrained airports (e.g., New York JFK, Chicago O’Hare), enabling compliance with ICAO and FAA safety standards without expensive land expansion.
• Military Airfields: Cable and net/barrier systems are standard to safely recover high-performance jets, especially in cases of brake failure, high-speed aborts, or landing gear malfunctions.
• Joint-Use Airports: Airports supporting both civil and military operations often combine systems to cater to diverse aircraft and safety requirements.

Regulatory Context:
International bodies such as ICAO, FAA, and EASA recognize arresting systems as compliant solutions for runway safety, especially where full RESA cannot be implemented. ICAO Annex 14 and FAA Advisory Circulars (e.g., AC 150/5220-22B) provide standards for performance, installation, and maintenance.

Strategic Benefits:

• Risk Reduction: Arresting systems reduce the likelihood of runway excursions, a leading cause of aviation accidents.
• Operational Flexibility: They allow airports to maximize usable runway length without compromising safety.
• Cost Efficiency: Arresting systems offer targeted, cost-effective alternatives to major land acquisition or infrastructure projects.

Types of Aircraft Arresting Systems

1. Engineered Materials Arresting System (EMAS)

Definition:
EMAS is a passive, energy-absorbing bed of crushable materials, commonly lightweight concrete or recycled glass, installed at runway ends. Its surface supports airport vehicles, but if an aircraft overruns, the landing gear sinks into the material, which crushes in a controlled fashion to decelerate the aircraft safely.

Technical Details:

• Material: Cellular concrete or foamed silica, designed for predictable energy absorption.
• Bed Size: Length, width, and depth are tailored to the airport’s design aircraft and available space (typically 60–180 meters long).
• Performance: Certified to stop aircraft up to 70 knots (80 mph).
• Location: Used where RESA is insufficient.

Operational Use:
EMAS is only engaged during actual overruns, with no impact on normal operations. It is repairable and modular for quick restoration.

Manufacturers:
Runway Safe Group (EMASMAX®, greenEMAS®) is a leading supplier.

2. Cable-Based Arresting Systems

Definition:
These active systems use high-tensile steel cables stretched across the runway, attached to energy absorbers (hydraulic or friction-based). Aircraft equipped with tailhooks engage the cable, which absorbs their kinetic energy during deceleration.

System Types:

• BAK-12: Fixed energy absorber using friction brakes, with a runout of ~950–1,200 feet.
• BAK-14/Type H: Retractable cable systems, lowered beneath the runway during civil operations.
• MAAS (Mobile Aircraft Arresting System): Portable, trailer-mounted versions for temporary or expeditionary use.

Performance:

• Max speed: Up to 180 knots.
• Reset time: 3–10 minutes after use.
• Maintenance: Regular tensioning, inspections, and brake overhauls.

3. Net/Barrier Arresting Systems

Definition:
Net or barrier systems deploy a high-strength nylon net across the runway or overrun area. The net engages the aircraft’s landing gear or fuselage, attached to energy absorbers to decelerate the aircraft.

System Types:

• BAK-15: Electro-hydraulically deployed for aircraft without tailhooks.
• MA-1/MA-1A, E-5/E-6: Variants for different operational needs.

Limitations:
While effective for military aircraft, nets may damage commercial airliners and are thus rarely used in civil settings.

4. Mobile Aircraft Arresting Systems (MAAS)

Definition:
MAAS are portable, trailer-mounted arresting systems based on BAK-12 technology. They are rapidly deployable for temporary airfields, emergency/expeditionary use, or disaster relief.

Deployment:
Installed in around two hours by a trained team, with components including energy absorbers, pendant cable, and steel anchors.

Technical Specifications and Components

Components:

• Energy Absorber: Converts kinetic energy to heat or mechanical work.
• Engagement Mechanism: Tailhooks (cable), net (barrier), or landing gear (EMAS).
• Runout Distance: Engineered based on aircraft weight, speed, and site.

Operational Scenarios and Use Cases

Civil Aviation

EMAS is preferred for commercial airports lacking full RESA, such as those in dense urban or coastal locations. It has stopped multiple overrunning aircraft at airports like JFK and O’Hare, preventing accidents and saving lives. Cable and net systems, where present, are carefully coordinated to avoid interference with civil operations.

Military Aviation

Cable and net/barrier systems are standard for high-speed tactical and training aircraft. MAAS is used for rapid deployment, temporary airfields, or emergency runway repair.

Joint-Use Airports

Airports serving both civil and military traffic may combine EMAS and cable/net systems, employing operational protocols, markings, and NOTAMs to maintain safety for all users.

Benefits and Limitations

Engineered Materials Arresting System (EMAS)

Benefits:

• Compatible with all aircraft types
• No impact on routine operations
• Predictable, low-impact stopping
• Rapid, modular repair
• Enables regulatory compliance without major infrastructure changes

Limitations:

• One-time use per event, requires repair after engagement
• Space and cost constraints may limit feasibility at some airports

Cable and Net/Barrier Systems

Benefits:

• Essential for military aircraft with tailhooks or requiring net engagement
• Reusable after reset and inspection
• Some models retractable for civil operations

Limitations:

• Only compatible with specific military aircraft (cable)
• Nets can cause damage to commercial aircraft
• Regular maintenance and operator training required

Mobile Arresting Systems (MAAS)

Benefits:

• Rapidly deployable for temporary or emergency use
• Maintains airfield safety in contingency situations

Limitations:

• Requires logistics support for movement and setup
• Limited to aircraft equipped for cable engagement

Conclusion

Arresting systems, whether EMAS, cable, net/barrier, or mobile, are indispensable for modern runway safety. They enable airports to protect passengers, crew, aircraft, and infrastructure, especially where standard safety areas aren’t feasible. With ongoing technological advancements and regulatory support, arresting systems will continue to play a vital role in safeguarding aviation operations worldwide.

If you want to learn how arresting systems can benefit your airport, contact us or schedule a demo today.