Mission critical

The aircraft is highly dependent on the navigating system. Air navigation is accomplished with many methods. Dead reckoning utilizes visual checkpoints along with distance and time calculations. The flight computer system aids the pilots to calculate the time and distance of the checkpoint that they set. The radio navigation aid (NAVAIDS) enables the pilots to navigate more accurately than dead reckoning alone, and in conditions of low visibility, radio navigation is handy. GPS is also used by pilots and uses 24 U.S. Department of Defence satellites to provide precise locational data, which includes speed, position, and track.[9]

If two-way radio communication malfunctions, the pilots have to follow the steps in the Title 14 of the Code of Federal Regulations (14 CFR) part 91. Pneumatic system failure, the associated loss of altitude, and various unfamiliar situations may cause stress and loss of situational awareness. In this case, pilot should use instruments such as navigators to seek more information about the situational data. In this case, the malfunction of the navigation system would be mission critical and would cause serious consequences.[10][11][12]

Nuclear reactor is a system that controls and contains the sustained nuclear chain reaction. It is usually used for generating electricity, but can also be used for conducting research and producing medical isotopes.[13] Nuclear reactors have been one of the most concerning systems for public safety worldwide because the malfunction of a nuclear reactor can cause a serious disaster.[14] Controlling the nuclear reactor system is accomplished by stopping, decreasing, or increasing the chain reaction inside the nuclear reactor. Varying the water level in the vertical cylinder and moving adjuster rods are the methods of controlling the chain reaction when the reactor is operating. Temperatures, reactor power levels, and pressure are constantly monitored by the sensitive detectors.[15]

The Transport Layer Security (TLS; formerly, Secure Socket Layers, SSL) refers to the standard security technology of networking protocol that controls and manages client and server authentication, and encrypt communication. This is usually used in the online transaction websites such as PayPal[20] and Bank of America,[21] which if systems are downed or hacked, will cause serious problems to the society and the companies themselves. In TLS, public-key and symmetric-key (encryption) are used together to secure the connection between two machines. Usually it is utilized in mail services or client machines that communicates via internet. To use this technology, the web server requires a digital certificate and this can be obtained through completing several questions about the identity of the website and get public keys and private keys (cryptographic keys). The industries using this technology may be also required to pay certain amount of money annually.

Nuclear power plants need safety systems to avoid mission-critical failures. The worst possible consequence that can result is leakage of radioactive materials (U-235 or Pu-239). One of the systems to avoid mission critical failures for nuclear power plants is shutdown system. It has two different forms: rod controls and safety injection control. When a problem occurs in the nuclear power plant, the rod control shutdown system drops the rods automatically and stops the chain reaction. The safety injection control injects liquid immediately when the system faces the problem in nuclear reactor and stops the chain reaction. Both systems are usually automatically operated, but also can be manually activated.[22][23]

Real time is responsiveness of a computer that makes the computer to continually update on external processes, and should process the procedure or information in a specified time, or could result in serious consequences.[24] Video games are examples of real time since they are rendered by computer so rapidly, it is hard to notice the delay by the user. Each frame must be rendered in a short time to maintain the experience of interactivity. The speed of rendering graphics may vary according to the computer systems.[25]

• Hard real-time system shouldn't miss the specified time or can result in serious consequences. It is non-negotiable in timing and it is "wrong answer" if the deadline is missed. The example of hard real time system is airbags for cars.[26]
• Soft real-time system has more loose deadline. The system can handle the problems and functions normally even though the deadline is missed, but their functionality depends on fast-paced processes. An example for soft-real time can be typing, which, if delayed, people will get annoyed, but answer still is correct.[27]
• Non real-time system doesn't have certain or absolute deadlines. However, the throughput of the activity of performance can still be very essential.[28]

Real time is a software that if specific time is not met, it fails, but mission critical is a system if failed, will result in catastrophic consequences. Although they go hand-in-hand, since real time can be mission critical, they are not the same concepts. These two are often confused by many people, but they are different concepts, but associated with each other.[29][30]

From the perspective of social function (i.e.: preserving society's life support structure, and overall structure intact), Mission critical aspects of social function would necessitate the provision of basic needs for society. Such basic needs are often said to include food (this includes food production and distribution), water, clothing (not an immediate need in an emergency), sanitation (sewage is an immediate need, but physical waste/garbage/rubbish disposal is not an immediate need in an emergency), housing/shelter, energy (not immediate) and health needs (not immediate in a healthy population). The prior list is not exhaustive. Longer term needs might include communications/transport needs in a developed population. This list of needs is associated with mission critical personnel in a clear manner - food production requires farmers, food distribution requires transportation personnel, water requires water-infrastructure maintenance personnel (a long term requirement if existing water infrastructure has been maintained to a high standard), clothing tends to require individuals to maintain clothes production infrastructure, similarly for sanitation. In emergencies, housing/shelter requires someone to build the shelter and maintain it over the long term if necessary. Health needs are met by doctors, nurses and surgeons. Implicit use of infrastructure requires personnel to maintain that infrastructure also - so food transportation requires not only that there are drivers for food trucks, but also that (over the long term) there are highways maintenance personnel who can maintain the roads, traffic infrastructure and signs for the roads, this in turn requires power supply personnel to provide power for traffic lights, etc... In this light, mission-critical systems have a complex dependency network which enables analysis of the level of interconnected dependencies between different aspects of a mission-critical system, which can be useful in planning, or just for gaining a truthful picture of how mission criticality is organised in complex systems. This would enable the determination of choke points in a complex system, points at which a mission-critical system (or set of systems) is vulnerable in one sense or another. Ideas that relate to human resources and human resources planning (making use of Gantt charts for project management, etc...) are also relevant.

Mission criticality depends upon the timescale associated with basic needs or other deemed mission-critical factors. Over the medium term (often taken to be 10 years) and the long term (which can go into 50-60 year timescales), the planning for mission-critical systems will clearly differ from short-term mission-critical systems planning. Mission-critical personnel can be considered part of the mission-critical systems planning paradigm but require a different approach to technological or mechanical aspects of mission-critical systems (i.e.: they require human resources planning).

Psychometrics enables the determination and characterisation of various psychological aspects of mission-critical personnel (e.g.: their IQ in the case of highly skilled work, such as nuclear physics, for example). Some jobs require physical standards (for instance, in the army), or physical dexterity (e.g.: surgeons). There exist methods and means of characterising the types of skills, qualities and other attributes that certain mission-critical job roles require, and these can be used as benchmarks for determining whether certain individuals are well suited to a particular mission-critical job role, or what assistance a less qualified (or even less capable) individual would need in performing a certain mission-critical job role which might be beyond their abilities (such measures might have to be taken in emergency situations).