Reducing runway safety risk remains a top priority for the FAA. The FAA created the Surface Safety Metric (SSM) to more accurately identify the greatest risks in the runway environment. Unlike previous metrics that focused on the number and severity of runway incursions, the SSM incorporates all types of relevant events that occur in the runway environment. The Surface Safety Risk Index is the methodology used to assess the severity of risk of those events. In October 2019, the SSM became the FAA’s primary metric for measuring and reporting the safety performance of the National Airspace System (NAS) in the runway environment.
What is the Surface Safety Risk Index?
The Surface Safety Risk Index is the methodology developed by the FAA to assess the severity of risk of runway safety events. It uses modeling to assign risk weights to the outcome of an event such as aircraft damage, injuries, and fatalities. The weights are based on proximity to a fatality and give credit for saving lives and minimal aircraft damage. It includes all manner of operations (commercial and non-commercial), aircraft, vehicles and pedestrians that occur in the runway environment. It includes runway collision accidents, runway excursion accidents, taxiway collision accidents, runway incursion incidents, runway excursion incidents, and taxiway surface incidents. Operations are defined as total takeoffs and landings. Commercial operations are considered those operating under Federal Aviation Regulations (FAR Parts 121, 129, and 135; all other operation types are considered non-commercial.
Risk-Based Safety Management
As the FAA evolves from compliance-based safety assurance methodologies to Risk-Based Safety Management (RBSM), we are able to focus on a systemic view of the runway environment that leads to the identification of risk before it becomes an event. RBSM manages aviation safety systemically through a continuous and comprehensive application of investigative, reporting, analysis, mitigation, measurement and feedback endeavors through both dynamic and static processes. It enables predictive capabilities through the early recognition of risk data patterns, which drives preventive risk mitigation.
Aviation Risk Identification and Assessment
Aviation Risk Identification and Assessment (ARIA) is an automated tool that supports risk-based, data-driven decision-making, providing better insight into potential risk in the NAS. At surface surveillance-equipped airports, the ARIA surface module will use surveillance data to identify and categorize potential risk of collision between an aircraft and moving objects (i.e., another aircraft, vehicle, etc.) within a predetermined area on or surrounding the airport environment. The system will continually assess and capture data about such encounters based on vertical, lateral, and speed components. This data will enable safety experts to make better-informed, risk-based, data-driven decisions about safety in the airport surface environment. ARIA surface module pre-deployment processes are underway with full deployment on target for 2022.
Collaboration is Key
The FAA convened the Runway Safety Council (RSC) to fundamentally change the existing safety culture and move toward a systemic proactive management strategy that involved cooperation throughout the FAA and among the different segments of the aviation industry. By applying the formalized and proactive approach of the Air Traffic Organization’s (ATO) Safety Management System, the RSC is advancing the shift from a compliance-based safety system to a risk-based, data-driven, integrated systems solution to runway safety.
Collaboration with the aviation community is a key component of runway safety. The RSC includes aviation stakeholders from across FAA Lines of Business like Airports, Aviation Safety, and the ATO, FAA employee labor organizations like PASS and NATCA, as well as industry representatives like aircraft operators, airline representatives and flight instructors.
Runway Safety Action Teams
Runway Safety Action Teams (RSAT) bring local airport stakeholders together at least once a year to identify risks to surface safety at that airport and develop plans to mitigate or eliminate those risks. RSATs provide the foundation of the Runway Safety Program at individual airports. The RSAT meetings are the primary forum for pinpointing and addressing airport-specific risk in the surface environment. The product of a RSAT meeting is a Runway Safety Action Plan in which the stakeholders document and agree to pursue specific actions intended to improve surface safety.
Runway Safety Technologies and Progressions
Runway Status Lights (RWSL)
The FAA developed RWSL technology to increase situational awareness for aircrews and airport vehicle drivers, and thus serve as an added layer of safety. A RWSL system derives traffic information from surface and approach surveillance systems and illuminates red in-pavement airport lights to signal a potentially unsafe situation. Runway Entrance Lights are deployed at taxiway/runway crossings and illuminate if it is unsafe to enter or cross a runway. Takeoff Hold Lights are deployed in the runway by the departure hold zone and illuminate red when there is an aircraft in position for departure and the runway is occupied by another aircraft or vehicle and is unsafe for takeoff. RWSL is operational at 20 U.S. airports. Learn more about RWSL.
Airport Surface Detection Equipment, Model X (ASDE-X)
ASDE-X integrates data from a variety of sources, including radars, transponder multilateration systems and Automatic Dependent Surveillance – Broadcast (ADS-B) to provide accurate target position and identification information and thus give controllers a more reliable view of airport operations. ASDE-X provides tower controllers a surface traffic situation display with visual and audible alerting of traffic conflicts and potential collisions. ASDE-X is operational at 35 airports in the U.S. There is more information about ASDE-X on the FAA website.
Airport Surface Surveillance Capability (ASSC)
ASSC is similar to ASDE-X. It improves surface surveillance and situational awareness in all kinds of weather. With ASSC air traffic controllers see aircraft and ground vehicles on the airport surface, and on approach and departure paths within a few miles of the airport. Like ASDE-X, ASSC fuses data from multiple sources including radars, ASSC multilateration remote units, to provide a highly accurate display for controllers with the same visual and aural alerting capabilities. ASSC is operational at eight airports in the U.S. Learn more about ASSC.
ASDE-X and ASSC Taxiway Arrival Prediction (ATAP)
ATAP is an enhancement to the ASDE-X and ASSC alerting capabilities that warns air traffic controllers that an aircraft is aligned with a taxiway rather that the assigned runway. At this time ATAP is enabled at 33 of the 35 ASDE-X airports and on target for all 35 by the end of fiscal year 2021. ATAP will be enabled at all eight ASSC airports in 2022.
Engineered Material Arresting System (EMAS)
EMAS technology provides safety benefits in cases where land is not available or it’s not possible to have the standard 1,000-foot runway overrun. A standard EMAS installation can stop an aircraft from overrunning the runway at approximately 80 miles per hour. An EMAS arrestor bed can be installed to help slow or stop an aircraft that overruns the runway, even if less than a standard RSA length is available. EMAS uses crushable material placed at the end of a runway to stop an aircraft that overruns the runway. The tires of the aircraft sink into the lightweight material and the aircraft is decelerated as it rolls through the material. EMAS is installed 111 runways across 66 airports. Learn more about EMAS.
Electronic Flight Bag (EFB) with Moving Map Displays
EFB, Moving Map Displays and Aircraft Own-Ship Position help pilots determine where their aircraft is on the airfield thereby reducing confusion and the risk of being in the wrong place. FAA guidance allows operators to use Commercial-Off-The-Shelf equipment and applications (Apps). This helps reduce the cost and give pilots a way to display own-ship position on the ground. Rapid and constant advances in technology provide more cost effective options than ever before. For example, some vendors now highlight runways and airport hot spots with the option of audible warnings as you approach them. Learn more about EFB in the “Safe and Sound on the Ground: An EFB Approach to App-roach to Improving Surface Safety” article in the March/April 2021 FAA Safety Briefing Magazine.
Runway Safety Areas (RSA)
The RSA is a defined surface surrounding the runway, typically 500-feet wide and extending 1,000-feet beyond each runway end. It provides a graded area in the event that an aircraft overruns, undershoots or veers off the side of the runway (runway excursion). Because many runways were built before the 1000-foot RSA standard was adopted, the FAA implemented the Runway Safety Area Program to make practicable improvements to the RSA for priority runways. Improvements were made to over 1000 runways at 500 airports. Although the original RSA improvement projects are complete, the program continues to evolve in order to address safety risk and plan for future improvements.
Runway Incursion Mitigation (RIM)
The RIM program is a national initiative at airports with a history of runway incursions to identify airport specific risk factors that might contribute to a runway incursion. These risk factors may include unclear taxiway markings, airport signage, and more complex issues such as the runway or taxiway layout. The FAA then works with the airport sponsors to develop strategies to mitigate runway incursions at these locations. As of May 2021, 129 RIM locations have been identified across 78 airports, 65 locations have been mitigated. Physical changes such as taxiway reconfigurations and changes to lighting, markings and aircraft operations are made when possible. Other solutions like an education campaign or a hot spot designation are employed when physical changes are not feasible or best suited. There is a 77-percent average reduction of runway incursions at RIM locations with mitigations. The RIM program continuously monitors these locations for reoccurrence as well as assessing incoming data for any new RIM candidates.
Hot Spot Standardization
As part of the FAAs Top 5 Initiative on Wrong Surface Operations, Runway Safety has been working on standardized symbology for Hot Spots on airport diagrams. Currently, there are numerous shapes on airport diagrams that have no meaning and can be confusing to the pilot community. A workgroup developed three shapes that will be utilized for Hot Spots. Surface Based Hot Spots will have either a circle or ellipse, whereas the Wrong Surface Hot Spot will be a cylinder. This standardization will better aid the pilot and provide less clutter to the airport diagrams. In addition to the Hot Spot Standardization a new Arrival Alert Notice is being created to highlight those airports with known wrong surface operations. This visual graphic will provide a cockpit view of the approach to a particular airport, along with verbiage to outline the confusion as to a possible wrong surface operation.
National Runway Safety Plan (NRSP)
The FAA’s top priority is maintaining safety in the National Airspace System with great emphasis placed on reducing runway safety risk. The National Runway Safety Plan (NRSP) aligns the strategic priorities of the FAA’s Runway Safety Group with established Safety Risk Management principles. The NRSP describes how the FAA, airport operators, and aviation industry stakeholders collaborate and use data-driven, risk-based decision making to enhance the safety performance in the runway environment and the airspace.
The Regional Runway Safety Plans support the NRSP by focusing on regional and airport specific efforts that contribute to the overall impact of the Runway Safety Program.
From the Flight Deck and the Runway Safety Pilot Simulator
FAA's From the Flight Deck video series provides pilots with actual runway approach and airport taxiway footage captured with cockpit mounted cameras, combined with diagrams and visual graphics to clearly identify hot spots and other safety-sensitive items. From the Flight Deck videos are available for airports nationwide, with new locations regularly produced, as well as videos on general aviation safety challenges pilots may encounter.
FAA's Runway Safety Pilot Simulator video series is a self-guided resource to assist flight instructors with teaching student pilots surface safety best practices, before they step foot into the cockpit. It allows student pilots to navigate on airport surfaces while communicating with air traffic control and following instructions provided. The scenarios are interactive and allow viewers to make decisions based on air traffic control instructions.