Landing and Takeoff Area Incursions and Excursions: A Comprehensive Guide

Introduction

Runway incursions and excursions represent significant safety concerns in aviation, potentially leading to catastrophic consequences. These events occur in the critical phase of flight where aircraft are either landing or taking offthe periods with the highest risk of accidents.

Understanding these phenomena, their causes, prevention strategies, and technological solutions is essential for maintaining the safety and efficiency of air transportation worldwide. This comprehensive guide aims to provide aviation professionals, airport operators, and aviation enthusiasts with valuable insights into both runway incursions and excursions.

Runway Incursions

Classification of Runway Incursions

The International Civil Aviation Organization (ICAO) classifies runway incursions into four categories based on severity:

• Category A: A serious incident in which a collision was narrowly avoided.
• Category B: An incident in which separation decreases and there is a significant potential for collision, which may result in a time-critical corrective/evasive response.
• Category C: An incident characterized by sufficient time/space to take action to avoid a collision.
• Category D: An incident that meets the definition of a runway incursion but with no immediate safety consequences.

Causes of Runway Incursions

Multiple factors contribute to runway incursions. Understanding these root causes is crucial for developing effective prevention strategies:

• Pilot Deviation: Pilots entering an active runway without proper clearance, misunderstanding taxi instructions, or making navigation errors on the airport surface.
• Operational Error/Deviation: Air traffic controllers improperly issuing clearances, failing to ensure runway separation, or providing inadequate instructions.
• Vehicle/Pedestrian Deviation: Airport vehicles or pedestrians entering unauthorized areas of the airfield, particularly active runways.
• Communication Issues: Misunderstandings between pilots and controllers due to similar-sounding runway designations, readback/hearback errors, language barriers, or non-standard phraseology.
• Situational Awareness: Loss of awareness of the aircraft's position relative to critical areas of the airfield.
• Airport Design: Complex taxiway layouts, confusing signage, inadequate lighting, or poor geometry that increases complexity.
• Weather Conditions: Reduced visibility due to fog, rain, or snow obscuring markings, signage, and other aircraft.

Runway Excursions

Types of Runway Excursions

Runway excursions typically fall into two main categories:

• Veer-off: When an aircraft maintains contact with the runway but leaves the runway surface to the side.
• Overrun: When an aircraft travels beyond the end of the runway, typically during landing when insufficient stopping distance remains or during takeoff when the aircraft fails to become airborne.

Causes of Runway Excursions

Runway excursions often result from a complex interplay of factors:

• Excessive Approach Speed: Landing above the recommended speed increases required stopping distance.
• Unstable Approach: Approaches outside the desired parameters in terms of speed, configuration, glide path, or alignment.
• Touchdown Point: Landing too far down the runway reduces available stopping distance.
• Delayed Braking/Reverse Thrust: Not initiating deceleration promptly after touchdown.
• Contaminated Runways: Water, snow, ice, or rubber deposits reducing friction levels.
• Mechanical Issues: Brake system failures, anti-skid system malfunctions, or thrust reverser problems.
• Aircraft Overweight: Landing above maximum landing weight or with improper load distribution.
• Weather Factors: Tailwinds, crosswinds, windshear, or reduced visibility.
• Pilot Technique: Improper landing techniques, delayed decision-making, or failure to go around when conditions warrant.

Prevention Strategies

Preventing Runway Incursions

A multi-faceted approach is required to effectively prevent runway incursions:

• Standard Phraseology: Strict adherence to ICAO standard phraseology to minimize communication misunderstandings.
• Cross-checking Procedures: Implementing thorough cross-checks of clearances and instructions between pilots and between pilots and controllers.
• Situational Awareness Enhancements: Encouraging "situational awareness" as a primary consideration for all personnel operating on the airfield.
• Training Programs: Regular and comprehensive training covering airport operations, signage, markings, and communications.
• Airfield Design Improvements: Implementing better signage, lighting, pavement markings, and taxiway geometry to reduce confusion.
• Runway Safety Areas: Maintaining clear and safe areas around runways free of obstacles.
• Control Tower Improvements: Enhancing tower visibility and implementing better scanning procedures.

Preventing Runway Excursions

Effective prevention of runway excursions requires attention to both operational and infrastructure factors:

• Stabilized Approach Criteria: Establishing and adhering to stabilized approach parameters for both visual and instrument approaches.
• Precision Landing Techniques: Emphasizing proper aim points, touchdown zones, and deceleration techniques.
• Go-Around Decision-Making: Encouraging pilots to execute go-arounds when approach parameters are outside acceptable limits.
• Weather Assessment: Thorough evaluation of weather conditions and their potential impact on stopping performance.
• Runway Condition Reporting: Improved standardized reporting of runway surface conditions and braking action.
• EMAS (Engineered Materials Arresting Systems): Installing EMAS at runway ends to safely stop aircraft that overrun.
• Performance Calculations: Accurate calculation of required landing distance considering all factors including aircraft weight, configuration, and runway conditions.

Technological Solutions

Advances in technology have significantly contributed to reducing both runway incursions and excursions:

Runway Incursion Prevention Technologies

• Airport Surface Detection Equipment (ASDE-X): Radar system that tracks aircraft and vehicles on the airport surface, providing controllers with real-time position information.
• Runway Awareness and Advisory System (RAAS): Cockpit system that provides aural advisories to pilots regarding runway position and nearby traffic.
• Electronic Flight Bag (EFB) Applications: Moving map displays showing aircraft position on the airport surface.
• Automatic Dependent Surveillance-Broadcast (ADS-B): Enhanced surveillance technology providing more accurate position information.
• RUNWAY STATUS LIGHTS (RWSL): Automated system of lights embedded in pavement that directly warns pilots and vehicle operators when it's unsafe to enter or cross a runway.

Runway Excursion Prevention Technologies

• Head-Up Display (HUD) Systems: Projecting critical flight information directly onto the pilot's forward view, improving situational awareness during approaches and landings.
• Enhanced Flight Vision Systems (EFVS): Using infrared cameras to provide images in reduced visibility conditions.
• Automated Braking Systems: Systems that can automatically apply maximum braking during contaminated runway operations.
• Runway Friction Measuring Devices: Improved equipment for accurately measuring pavement friction capabilities.
• Precise Landing Performance Calculators: Advanced FMC or EFB-based systems that calculate required landing distance under current conditions.

Case Studies

Tenerife Airport Disaster

On March 27, 1977, two Boeing 747 passenger jets collided on the runway at Los Rodeos Airport (now Tenerife North Airport) in the Canary Islands, resulting in 583 fatalities. The accident was caused by a combination of factors including dense fog, communications issues, and distraction. The KLM flight began its takeoff roll while the Pan Am flight was still on the runway. This tragedy led to significant changes in communication procedures and crew resource management training worldwide.

San Francisco Airport Runway Incursion

On July 7, 2017, Air Canada Flight 759 lined up to land on a taxiway instead of the runway at San Francisco International Airport. Four aircraft were waiting on that taxiway for takeoff. The aircraft missed colliding with the first plane by about 14 meters (46 feet). This incident highlighted the importance of vigilance, situational awareness, and prompted reevaluation of procedures and airport designs.

Air France Flight 358 Runway Excursion

On August 2, 2005, an Airbus A340-300 (Flight 358) overran the end of runway 24L at Toronto Pearson International Airport after landing during a thunderstorm. The aircraft traveled into a ravine and caught fire. All 309 passengers and crew survived. The investigation cited the crew's decision to land in rapidly deteriorating weather conditions, late deployment of spoilers and thrust reversers, and insufficient consideration of the aircraft's landing distance performance. This incident led to improved weather assessment protocols and reinforced the importance of go-around decisions when conditions warrant.

Conclusion

Runway incursions and excursions remain significant challenges in aviation safety. While the number of these events has decreased over the years thanks to technological advancements, improved procedures, and enhanced training, continued vigilance is necessary.

Effective prevention requires a comprehensive approach that addresses human factors, operational procedures, airport infrastructure, and technological solutions. It's a shared responsibility among pilots, air traffic controllers, airport operators, aircraft manufacturers, and aviation authorities.

The integration of advanced technologies with improved training and standardization of procedures offers the best path forward for further reducing these events. As aviation continues to grow globally, maintaining and improving runway safety will remain critical to the industry's success and its commitment to passenger and crew safety.

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