*Military Aviation Principles DOI: http://dx.doi.org/10.5772/intechopen.87087*

*Military Engineering*

ture point of view on the other.

'extremely improbable' (1 in 107

**6.3 Flight safety directorate**

an event and the degree of hazard inherent in its effect.

infinite cost. Therefore, the airworthiness standards have to balance between safety concerns on the one hand and the cost and practicability from design and manufac-

In aviation, safety may be defined as freedom from death, injury or damage to people on board and loss property and life on ground (accident). Safety of any flying effort or machine would depend primarily upon, whether we are operating below or above a particular level known as 'risk threshold'. The risk threshold is the level of risk beyond which accidents are inevitable. It also must be appreciated that this 'risk threshold' is not a stationary one and it keeps varying based on the role, function and a host of other associated factors. It needs therefore to be reassessed under each changing scenario. Airworthiness control is to minimize the risk and maximize the effectiveness. All the airworthiness standards, military or civil, whether that of the USA, Europe or Russia, have a common point of reference which is that an inverse relation should exist between probability of occurrence of

For military aircraft in the US Department of Defense (DoD) document, Mil-STD-882 defines the safety requirements during design of an airborne stores. The decision matrix of system safety as per Mil-STD-882 is shown in **Figure 8**. The safety requirement of any failure event is based on the hazard index of the failure which is defined as the product of the probability of the failure and the damage consequent of the failure event. The damage consequences can range from 'catastrophic' (loss life, aircraft and property) to negligible (minor inconvenience). The frequencies of occurrences are grouped under 'frequent' (1 in 10 h of flight) to

flight hours).

The operational branches of both military and civil aviation are expected to have effective 'flight safety directorates'. The primary responsibility of the flight safety directorate is to estimate the risk threshold under all dynamic condition, take appropriate measures and ensure that operational risk does not exceed this value. The basic aim of the flight safety studies is to ensure that the chances of achieving the mission tasks be optimal, while operational risks are minimal. In military aviation, the flight safety directorate has a very complex duty to perform. On the one hand, the military training must give a high level of exposures to possible war scenario and threats,

**16**

**Figure 8.**

*Mil-STD-882: design safety decision matrix [14].*

while it must ensure that the high level of risks are to be avoided in peace time within the stated training syllabi. This is because the accidents have very deleterious effects on the morale of the flier. During the war time, however, task achievement is paramount, and hence risks are to be taken even at high degrees if the operational requirements dictate. The main purposes of the flight safety studies are therefore to:

