2.2.4   Safety Order of Precedence  Managing Safety Risk in a System of Systems  Section 2  The methods for reducing safety risk generally fall under one of the four categories that make  up the Safety Order of Precedence. The Safety Order of Precedence categorizes safety risk  mitigations in the following order of preference:  Table 2.1: Safety Order of Precedence and Examples  Priority  Definition  Example  1.  Design for minimum risk  - Design the system (e.g.,  operation, procedure, human-to-system interface, or  NAS equipment) to eliminate risks. If the identified  risk cannot be eliminated, reduce it to an acceptable  level by selecting alternatives.  Remove intersection point by  removing concrete, preventing  planes from ever crossing the  same area.  2.  Incorporate safety devices  - If identified risks cannot  be eliminated through alternative selection, reduce the  risk by using fixed, automatic, or other safety features  or devices, and make provisions for periodic function  checks.  Install physical stop bars and  lights to ensure pilots cannot  cross unauthorized runways or  intersection points.  3.  Provide warning  - When alternatives and safety  devices do not effectively eliminate or reduce risk, use  warning devices or procedures to detect the condition  and produce an adequate warning. The warning is  designed to minimize the likelihood of inappropriate  human reaction and response, and must be provided  in time to avert the hazard’s effects.  Install a lighting system to alert  pilots/controllers of potential  unauthorized crossings.  Provide new runway or taxiway  markings.  4.  Develop procedures and training  - Procedures and  training are used when it is impractical to eliminate  risks through alternative selection, safety features,  and warning devices. However, management must  concur when procedures and training alone are  applied to reduce risks of catastrophic or hazardous  severity.  Develop new taxi and  departure/arrival procedures for  intersecting runway operations.  Train pilots and air traffic  controllers on new procedures  for intersecting runways.  Note: Reliance solely on training is not normally a sufficient means to mitigate safety risk.  17 2.2_SMSM_201904  Originally published April 2019  Uncontrolled copy when downloaded