Managing Risks in sUAS Operations

Operational Risk Management 

     There are several forms of hazards analysis and tools including the use of a preliminary hazards list and assessment (PHL, PHA), Operational Hazard Review and Analysis (OHR&A), and an Operational Risk Management (ORM) assessment tool. The use of hazards analysis throughout an entire process helps identify and mitigate risks that may be encountered during different stages of operations.

      For the purpose of this exercise we consider the operations of a Raven small UAS (sUAS). The Raven sUAS is popular in many combat operations particularly by the US Army. The Raven is hand-launched into flight by the operator which, in spite of its small size, presents the potential for the occurrence of many incidents and accidents. We consider for analysis two critical stages in Raven operations – the staging and launch phases.

     Using MIL-STD-882D/E we can identify the Severity Categories and Probability Levels listed in Tables 1 and 2. To determine the appropriate severity category as defined in Table 1 for a given hazard at a given point in time, identify the potential for death or injury, environmental impact, or monetary loss. A given hazard may have the potential to affect one or all of these three areas (MIL-STD-882E, 2012).

     To determine the appropriate probability level as defined in Table 2 for a given hazard at a given point in time, assess the likelihood of occurrence of a mishap. Probability level F is used to document cases where the hazard is no longer present. No amount of doctrine, training, warning, caution, or Personal Protective Equipment (PPE) can move a mishap probability to level F (MIL-STD-882E, 2012).

     Assessing the risk of a task, process or action using the Probability and Severity tables, when combined, results in a value conveyed as a Risk Code which is a combination of one severity category and one probability level. As an example, a Critical severity combined with a Remote probability results in a risk code of 2D. Table 3 assigns a risk level of High, Serious, Medium, or Low for each risk code.

     Using the three tables above one can assess the Risk Level (RL) for identified hazards. As shown in Table 4 a Raven sUAS staging and launch process is broken down into identified hazards, its probability of occurrence, the severity of risk, mitigating actions that can be used to reduce the risk, and the resultant level of risk after applying mitigating actions.

     The Operational Hazards Review and Analysis is used to identify and evaluate hazards throughout the entire process or operations. The OHR&A is essential to ongoing hazards evaluation and provides the necessary feedback to assess the effectiveness of mitigating actions. Similar in form to the PHL/A, the different column in an OHR&A is the Action Review column which lists the mitigating actions identified in the PHL/A and determines if they were satisfactory (Barnhart, 2011).

     One tool commonly used in Army operations is the Composite Risk Management (CRM) worksheet which uses a Department of the Army Form #7566. The worksheet identifies the tasks, hazards, risk level, the controls or mitigating actions, the residual risk level, how to implement controls, how to supervise, who will supervise, and answers whether or not the control is effective (DA Form 7566 Risk Management Worksheet , 2005). Using the Army’s CRM worksheet as a baseline an Operational Risk Management worksheet can be fashioned for use by the Raven sUAS operators to safely assess their ability to accomplish the mission.  

 Reference 

Barnhart, R. K. (2011). Introduction to Unmanned Aircraft Systems. London, GBR : CRC Press. DA Form 7566 Risk Management Worksheet . (2005, April). Retrieved from NCO Support: http://www.ncosupport.com/daforms/daform7566-riskmanagement.html

MIL-STD-882E. (2012). Washington, D.C.: Department of Defense.