acceptability. Risk management is unique to each and every  individual, since there are no two people exactly alike in  skills, knowledge, training, and abilities. An acceptable level  of risk to one pilot may not necessarily be the same to another  pilot. Unfortunately, in many cases the pilot perceives that his  or her level of risk acceptability is actually greater than their  capability thereby taking on risk that is dangerous. It is a decision-making process designed to systematically  identify hazards, assess the degree of risk, and determine the  best course of action. Once risks are identified, they must be  assessed. The risk assessment determines the degree of risk  (negligible, low, medium, or high) and whether the degree  of risk is worth the outcome of the planned activity. If the  degree of risk is “acceptable,” the planned activity may  then be undertaken. Once the planned activity is started,  consideration must then be given whether to continue. Pilots  must have viable alternatives available in the event the  original flight cannot be accomplished as planned.  Thus, hazard and risk are the two defining elements of risk  management. A hazard can be a real or perceived condition,  event, or circumstance that a pilot encounters. Consider the example of a flight involving a Beechcraft King  Air. The pilot was attempting to land in a northern Michigan  airport. The forecasted ceilings were at 500 feet with ½  mile visibility. He deliberately flew below the approach  minimums, ducked under the clouds, and struck the ground  killing all on board. A prudent pilot would assess the risk in  this case as high and beyond not only the capabilities of the  aircraft and the pilot but beyond the regulatory limitations  established for flight. The pilot failed to take into account the  hazards associated with operating an aircraft in low ceiling  and low visibility conditions.  A review of the accident provides a closer look at why the  accident happened. If the King Air were traveling at 140 knots  or 14,177 feet per minute, it would cover ½ statute mile (sm)  visibility (2,640 feet) in about 11 seconds. As determined in  Figure 1-1,  the pilot has 12.5 seconds to impact. This example  states that the King Air is traveling ½ statute mile every 11  seconds, so if the pilot only had ½ sm visibility, the aircraft  will impact before the pilot can react. These factors make  flight in low ceiling and low visibility conditions extremely  hazardous. Chapter 4, Aerodynamics of Flight, of the Pilot’s  Handbook of Aeronautical Knowledge presents a discussion  of space required to maneuver an aircraft at various airspeed.  So, why would a pilot faced with such hazards place those  hazards at such a low level of risk? To understand this, it  is important to examine the pilot’s past performance. The  pilot had successfully flown into this airport under similar  an eager participant with a stake in the flight’s execution.  Another simple step is to ask three questions—is it safe,  is it legal, and does it make sense? Although not a formal  methodology of risk assessment, it prompts a pilot to look at  the simple realities of what he or she is about to do.  Therefore, risk management is the method used to control,  eliminate, or reduce the hazard within parameters of  1-6 Figure 1-5.  Using a risk assessment matrix helps the pilot  differentiate between low-risk and high-risk flights.  Figure 1-4.  Types of risk.  Types of Risk The sum of identified and unidentified  risks. Risk that has been determined  through various analysis techniques.  The first task of system safety is to  identify, within practical limitations, all  possible risks. Risk not yet identified. Some  unidentified risks are subsequently  identified when a mishap occurs.  Some risk is never known. Risk that cannot be tolerated by the  managing activity. It is a subset of  identified risk that must be eliminated  or controlled. Acceptable risk is the part of identified  risk that is allowed to persist without  further engineering or management  action. Making this decision is a  difficult yet necessary responsibility of  the managing activity. This decision is  made with full knowledge that it is the  user who is exposed to this risk. Residual risk is the risk remaining after  system safety efforts have been fully  employed. It is not necessarily the  same as acceptable risk. Residual  risk is the sum of acceptable risk and  unidentified risk. This is the total risk  passed on to the user. Total Risk Identified Risk Unidentified Risk Unacceptable Risk Acceptable Risk Residual Risk Catastrophic Critical  Marginal  Negligible  Improbable Remote Occasional Probable Risk Assessment Matrix Likelihood Severity Serious Low Medium Serious Serious High High High