What obvious hazards are created by the installation of a six-way powered automobile seat into an aircraft that was not designed for this particular seat? Three hazards create three potential risk factors that must be assessed and mitigated for safe flying. If these risks are not mitigated by some type of action, the odds favoring an incident or accident increase. Hazards Weight of replacement seat Failure to use correct amp  in circuit breaker Seat covered in standard commercial material rather than material suited for use in aircraft Risk Can the aircraft tolerate the  increased weight of this  particular seat? Overheating and tripping the  circuit breaker Flammability Mitigate Risk by Recalculating weight  and balance Using correct amperage in  circuit breaker Recovering the seat in material  approved for aircraft use EVENT 1 Figure 6-4.  Example of an event diagram mapping hazards, risk assessment, and risk mitigation for the first event. The 5-amp circuit breaker was replaced with a 7-amp circuit  breaker to prevent excessive tripping. The event diagram in  Figures 6-4  and  6-5  maps the hazards,  risk assessment, and attempts to mitigate this accident.  While impact damage precluded the National Transportation  Safety Board (NTSB) from determining the cause of the  fire for the aircraft involved in this accident, the final report  discusses the possibility that one of the motors to the seat  overheated and ignited the seat cushion. They attributed this  possibility to the circuit breaker issue as well as the past  instance of the circuit breaker tripping when a large occupant  sat in the seat. It is probable that the installation of the replacement seat  started a chain of events diagramed above that led to a fatal  accident. The three hazards associated with the seat are  discussed more fully below:  As this accident demonstrates, for the pilot of an experimental  aircraft, assessing risk goes beyond the self-assessment  illustrated in the IMSAFE method. Hazard identification,  risk assessment, and its mitigation starts much earlier. The  construction method of manufacture and the materials used  impose a certain inherent risk that may not be apparent until  an adverse event occurs. Unfortunately, hindsight is of limited  value to the aircraft passengers and pilot, but do provide  others a better understanding of risk and its insidious nature.  The risk assessment matrix in  Figure 6-6  can provide lessons  from this accident. The vertical scale relates to the likelihood  of something happening, while the horizontal scale indicates  impact upon safety of the flight.  1. Effect of weight on the aircraft weight and balance and  its downstream performance—a seat with three motors  adds significant weight on one side to the aircraft.  Even with weight allowances, aircraft performance  would be affected.  6-4