An effective method to detect dangerous prohibited items is security manual control. Undoubtedly the greatest effectiveness is achieved by performing a manual control of all passengers; however it is impossible due to the throughput of the airport. The legal regulations require the manual control to be performed randomly. Taking into consideration the operational needs as well as the risk analysis of the susceptibility of a country to acts of unlawful interference a set minimum frequency of security manual controls is established. Of course if there is a suspicion that the particular passenger may attempt to bring a prohibited item onboard a plane then a detailed manual control must be performed.
As part of this study a survey was conducted in June 2014 among the persons responsible for the security policy at airports. Based on this survey we established the Frequency of manual controllinguistic input variable as presented in Fig. 4.
As it has already been mentioned, the variable Frequency of manual control describes the total frequency of manual control that is the aggregate of WTMD triggering events and additional controls. The first value depends on the WTMD’s sensitivity that may be set for the WTMD. If the sensitivity is increased the number of triggering events which require manual control is also increased. The number of additional controls is established by the entity managing the process of security control at an airport.