Risk Assessment: Tools, Techniques, and Their Applications

13.2 Critical Functions

Obviously, in both these accidents, critical functions of the airplanes failed. In both the cases, they were hardware components. The human component in both accidents succeeded. The components of an airplane are listed in Table 13.3, along with the functions that failed or succeeded in each event.

Table 13.3 Critical Functions of a Commercial Airplane

It is apparent from Table 13.3 that critical functions are dependent on each other in modern commercial airliners. Figure 13.1 shows how these functions are interconnected. Figure 13.2 shows how the diagram would change if the engines failed, for instance.

Figure 13.1 Interconnection of critical functions.

Figure 13.2 Flight during an engine failure event.

CFA then can be used to determine which critical functions are needed to support the desired mission. A recent Web article on www.globalsecurity.org listed the flight critical systems for the F-22 Raptor (17). These are listed in Table 13.4.

Table 13.4 Flight Critical Systems for F-22 Raptor

Flight critical system	Function
Vehicle management system (VMS)	The VMS provides integrated flight and propulsion control. The VMS enables the pilot to aggressively ...