text: Appendix A
  Probability (expected frequency)
  Frequent: Likely: Occasional Seldom: Unlikely:
  Continuous, Several or : Infrequent Possible
  regular, or numerous Sporadic or occurrences occurrences
  inevitable occurrences intermittent but
  occurrences occurrences improbable
  Severity (expected A B C D E
  consequence)
  Catastrophic:
  Death, unacceptable
  loss or damage, I EH EH H H M
  mission failure, or unit
  readiness eliminated
  Critical:
  Severe injury, illness,
  loss, or damage;
  II EH H H M L
  significantly degraded
  unit readiness or
  mission capability
  Moderate:
  Minor injury, illness,
  loss, or damage;
  III H M M L L
  degraded unit
  readiness or mission
  capability
  Negligible:
  Minimal injury, loss, or
  damage; little or no
  IV M L L L L
  impact to unit
  readiness or mission
  capability
  Legend
  EH – extremely high risk H – high risk M – medium risk L – low risk
  Figure A-2. Sample risk assessment matrix
  PREPARE
  A-15. In the preparation phase, leaders develop control measures and make decisions to eliminate
  unnecessary risks. Based on the identification and assessment of potential hazards by airspace personnel,
  leaders balance the risks (readiness, political, economic, and environmental) against the costs of each course
  of action as they develop control measures.
  A-16. In step three, after airspace control working group personnel have assessed related hazards and made
  appropriate recommendations, leaders develop one or more control measures. These control measures either
  eliminate the hazard or reduce the risk (probability or severity) of a hazardous incident occurring. In
  developing control measures, leaders consider the reason for the hazard, not just the hazard itself.
  A-17. To be effective, each control developed must meet the following criteria:
  * Feasibility. The unit has the capability to implement the control.
  * Acceptability. The benefit gained by implementing the control justifies the cost in resources and
  time. The assessment of acceptability is largely subjective. Past experience, the commander’s
  guidance, or other external restrictions influence the assessment.
  * Suitability. The control removes the hazard or mitigates (reduces) the residual risk to an acceptable
  level (determined by the responsible individual).