During flight pilots smell fire. At this point, the pilots are aware of a hazard. They choose to mitigate the risk by attempting to locate the source of the fire. As evidenced by their radio call, the pilots are unsure if the source of the fire is inside the aircraft or outside  the aircraft. One of the pilots contacts ATC to ask if any other pilot  has reported fire in the local area that would explain the  smell they have noticed. The controller replies that there are no reported ground  fires in the area. Within four minutes of the question about fire, the pilots  failed to respond to a transmission from ATC.  Controllers are notified by the police the airplane had  crashed into a building. Hazard Inflight fire Hazard Aircraft accident Mitigate Risk by Locating source of fire Making immediate  emergency landing EVENT 2 EVENT 3 EVENT 4 Figure 6-5.  Event diagram for events 2 through 4. Figure 6-6.  The installation of non-aviation parts can have a  profound effect. Catastrophic Critical Marginal Negligible Improbable Remote Occasional Probable Risk Assessment Matrix Likelihood Severity Serious Low Medium Serious Serious High High High 3.  Potential for electrical malfunctions, especially  overheating—why use a 5-amp and then a 7-amp  circuit breaker when a 30-amp circuit breaker was  used in the original automotive installation? •  Builder—the likelihood of an adverse event is  minimized when aviation standards are adopted in  both the selection of material and components, and  their installation. The more closely the standards are  followed, the less likely the occurrence of an adverse  event. In this case, the likelihood of an adverse event  is maximized not only because of the seat installation,  but that it represents a potential problem across the  construction of the entire aircraft. •  PIC—if he were familiar with the seat installation,  the problems it created, and its prior problem of  overheating, he failed to assess the likelihood that  the source of the smell was a fire in the aircraft and  not a fire on the ground. No information is available  on how long the occupants of the aircraft smelled the  smoke, but there were only four minutes between the  radio call requesting information about ground fires  and the impact with the building. This left the pilot  2.  Seat materials—the criteria for automobile materials  are different from those for materials suitable for use  in aircraft. Material coverings certified for aircraft  use provide additional safety and are intended to  reduce unnecessary exposure to fire. In this accident,  6-5 In  Figure 6-6,  the risk matrix relates directly to both the  builder of the aircraft and the PIC.  Did the pilot in command (PIC) take unnecessary risk?  Assuming he or she had no knowledge of the differences  between the replacement seat and a normal aircraft seat, he  should have questioned the installation of a non-aircraft part.  And, examine the PIC’s query to the controller during the  flight. He indicated he was not sure if his aircraft were on fire  or if something on the ground were on fire. Did he incorrectly  assess the information he had been given? Did he assume  his aircraft was not on fire? Given the seat’s installation,  its propensity to overheat, and the indication of a fire, what  should the pilot have done? the possibility exists that the seat covering on the  automotive seat exacerbated the fire. 