Civil aviation has developed at an unprecedented pace. It took only six decades for this branch to become one of the most popular types of passenger transport, overshadowing the railway. The world’s first airport with an airplane hangar was built in the French city of Issy-les-Moulineaux in 1907. Passengers appeared in 1908, but the first air cargo was delivered in 1910, while the first charter flight was made in 1911, and the first passenger transfer on schedule was made in 1914. In 1919, the first international passenger airlines began to operate. Tempelhof, the Airport of Berlin, is the oldest one in the conventional sense. The first regular flight was held on April 6, 1926, by the airline Deutsche Luft Hansa. It is noteworthy that in the 30s, Tempelhof surpassed airports of Paris, Amsterdam, and London.
Nowadays the number of passengers and flights has increased, technical maintenance of aircrafts and airports has developed, and security system has improved. Moreover, hundreds of technicians, engineers, physicists, security officers and other professionals around the world are constantly developing new tools and methods that can secure flights.
The main hazards during flights are falling objects such as debris, being items possibly provoking damages to aircrafts. Moreover, misleading and inadequate information from the pilot and their captain can lead them to wrong direction, causing disasters. Striking lightning during thunderstorms also causes aircraft damage and accidents. Furthermore, ice and snow in the mountains might hide landing and take-off of the aircraft.
Engine failure is usually the major failure of accidents that are commonly evidenced alongside structural failure of the aircraft. Talking about stalling and fire in the aircraft, they are caused by high pressure, leading to disasters. What is more, engine bird strikes may trigger fire or damage part of the aircraft, causing accidents. Ground damage due to the volcano eruption that may cause volcanic ash eruption prevents pilots from seeing the way, thereby leading to disasters. Human factors such as sleeping sickness and failure to repair damaged part of aircraft cause serious accidents that may trigger life loss. What is more importantly, electromagnetic interference causes failure of the whole aircraft. Terrorism and military actions that aim to hijack aircraft have become the main issue of the day due to self-interest.
Undoubtedly, modern aviation safety of passengers and crew is of paramount importance. There are a variety of devices installed on the ground and board to maintain it. Also, security services’ performance is constantly improving. The great attention is paid to the aircraft skin composites, while experts are trying to improve the design in order to prevent accidents.
Airport Improvements that Ensure Flight Safety from Takeoff to Landing
Safety Management Systems is among crucial things in aviation rules and regulations. In fact, the pilot and their captain must use combined Safety Management Systems methods to calculate risk before it happens. Target Level of Safety (TLS) is used as the maximum acceptable level of risk when calculating risk regulation. However, it should be stated that a particular risk level can be exceeded in practice.
Airport improvements that insure flight safety from take-off to landing include the creation of a runway end safety area to prevent effects of potential overrunning and undershooting, caused by adverse operational factors. According to Airports Council International, it endorses runway end safety area (RESA) that extends beyond the end of the runway strip to a minimum of 90 meters for code number 3 or 4 runways, which corresponds to a minimum of 150 meters beyond a runway end or stop way. Airport has improved with regard Advanced Surface Movement Guidance and Control Systems (A-SMGCS) that maintains safety levels and mitigates the possibility of runway incursions.
According to Diehl (2013), visual aids are one of the most important safety devices at airports. Most of modern airports have improved lighting system because it promotes an effective operation under the worst climate conditions such as fog without confusing pilots by excessive brightness, especially in the night.
Buildings and hills endanger aircraft taking off and landing because they provoke turbulence caused by strong winds on or in the vicinity of the runway threshold. Thus, ACI has recommended new design of buildings and landscape changing that would not affect the safety of aircraft operations. Apparently, airport aerodromes are equipped with bird dispersal devices such as acoustic and visual systems as well as pyrotechnics to prevent birds’ penetration into the runway because they cause a great threat to aviation. Moreover, airports have reared falcons and Border Collies to scare wild birds as natural predators. Airports have constructed fences around the airport to limit the possibility of mammals’ appearance on the airfield as much as possible. Also, modern airports are equipped with various devices which insure the safety of visitors. Visitors are screened in secure and sterile areas through exit gates to the aircraft to prevent loss of life, property, and accident.
Security staff has been trained to detect weapons or explosives; thus, airport checkpoint screening has been tightened considerably. Talking about the United States airport, it uses standard metal detectors and full-body scanning X-ray machines to detect weapons or explosives on passengers’ bodies. Also, another security innovation is the ID check which gives personal information on the passengers. Thus, an individual fly is allowed only with valid ID. It is possible to improve security through different programs intended for airports and aircrafts. Programs such as Secure Flight that is airline passenger pre-screening program aim to check personal information on identified persons. Moreover, a computer program called CAPPS II identifies the level of risk of passengers before they get on board by screening their personalities.
Air Traffic Control
Air traffic control is used to direct airplanes in the runway, reducing traffic within the airport. It also provides essential information and other support for pilots and their captains. For example, ground-based controller directs airplanes to the ground by insuring there is no object that can cause accidents.
Other methods used are visual observation from the airport in the control tower (TWR) and the use of radar to control the immediate airport environment. What is more, ground-based VHF unidirectional range stations are used to provide the pilots with essential information on radials in degrees to or from the station and slant range distance. Also, controllers use secondary surveillance radar for airborne traffic approaching and departing. Apparently, airport experts are replacing radars with satellite-based aids like Global Positioning System (GPS), which give accurate information about pilots’ location. Although GPS constellation is a single point of failure that one cannot be dependent on, ground-based navigation aids are still required.
Ground control also known as ground movement control maintains an orderly flow of air traffic at the airport movement areas. Ground control also aids local government in scanning active runways, acting as clearance delivery when there is no such service. Ground control is essential in insuring the smooth operation of the airport as this sector is responsible for aircrafts’ departure, safety and efficiency of the airport. Also, modern airports use local control to monitor and evaluate active runway surfaces. Local control supervises the aircraft while taking off or landing, controlling prescribed runway separation fulfillment. If any unsafe condition is detected, a landing aircraft may be ordered to go around through a terminal area controller. Communication between local control and ground control is conducted within the control tower (TWR). Local control gives approval to ground control to allow aircraft to cross runways.
Aircraft Systems that Provide Aircrew with Vital Information to Avoid Air Mishaps
In 1929, Jimmy Doolittle developed instrument flight. Hereby, flight instruments were equipped in the airplanes to give the pilot and captains essential information on the flight situation. Moreover, they provided data on weather conditions and those of the airplane such as altitude the aircraft is traveling at, speed of the airplane at the moment of flight, and direction it takes during the flight. Also, it helps in bad weather conditions with poor visibility such as in thick rainy clouds. From the late 1920s, several experimental radio-based navigation aids were developed. Moreover, various combinations were developed in the instrument landing systems (ILS). In 1932, an American pilot Albert Hegenberger made the first blind flight in the world, while being guided only by instrument readings.
Nowadays pilots use a lot of different instruments to conduct a safe flight. Thus, the altimeter determines the aircraft’s altitude above sea levels, measuring the difference between the pressure in a stack of aneroid capsules and environment. Moreover, the attitude indicator or artificial horizon shows the aircraft’s relation to the horizon. With regard to the airspeed indicator, it is used by modern aircrafts to indicate only speed of the airplane in knots relatively to the surrounding air. What is more, the compass and heading indicator show the aircraft’s heading relative to magnetic north. Talking about the vertical speed indicator, it displays information on changing air pressure. The course deviation indicator determines the aircraft’s lateral position in relation to the track. Furthermore, a radio magnetic indicator is being attached to an automatic direction finder (ADF), which is used to provide a compass card for the pilot on a tuned non-directional beacons (NDBs).
TCAR is a mutually developed active electronically scanned array radar sensor. It was created by a group of scientists from France, Germany, Italy, Netherlands, Spain and USA and combined the best features of radar programs in these countries. TCAR includes a considerable amount of software and programs such as the United States Multi-Platform Radar Technology Insertion Program and Europe’s Stand-off Surveillance software and Target Acquisition Radar demonstrator. In fact, TCAR provided situational information through a shared and linked common ground picture that is available to national rulers. Thus, TCAR is powerful radar that provides NATO safety flight supervision.
Weather radar is an important device, which promotes aircrafts’ safety by predicting precipitation and conditions. In fact, weather is a major factor in air traffic. The reason is that different weather conditions on the runway provoke difficulties for landing aircrafts. Thus, weather conditions such as fog in the day time reduce the safe arrival rate of aircrafts, thereby requiring more space between landing aircrafts. The most problematic weather is thunderstorm in Area Control Centers because it poses a variety of hazards to aircrafts. Thus, aircrafts change the route when there is a need for more space for each aircraft to reduce congestion.
Weather delays aircraft before taking off or landing. However, there are three levels of radar returns, which are used by pilots, dispatchers, and air traffic controllers. Talking about level 1, it shows green radar return and displays light rain and little turbulence, which can reduce visibility. With regard to level 2, it shows yellow radar return and indicates moderate rain, causing very low visibility, moderate turbulence and an uncomfortable flight for aircraft passengers. Concerning level 3, it shows red radar return to indicate heavy rain, possibility of thunderstorms, severe turbulence and structural damage to the aircraft (Stoen, H., 2001). Therefore, aircrafts try to avoid level 2 and 3 returns as much as possible unless they are specially designed research aircrafts.
CRM can be defined as a system of governance that allows one to use all available resources, equipment, procedures, and people to promote safety and efficiency of operations (Diehl, 2013). Cockpit resource management is a training program that provides steps for use in an environment where a human error can lead to catastrophic consequences. CRM training covers a wide range of knowledge and skills, including communications, situational awareness, problem-solving, decision-making and the importance of teamwork. The main elements of crew resource management are the basic elements and the building blocks for the system to work. Without these keys elements, the system will not operate but will be useless. Among key elements, there is setting of goals to develop an action plan.
Communicating and cooperating gives one the opportunity to know all goals and their work. In fact, cooperation is the joint work of the entire team, and each team member is contributing to expertise, monitoring and evaluation of feedback to achieve the objectives of the system. Moreover, feedback and monitoring insure that objectives of crew resource management are being developed and adjusted as necessary.
However, the basic elements and building blocks for the system to work are direct results, which are obtained by the basic elements of management. Hence, the output is the observance of health and safety processes, policies and procedures that insure a safe flight (International Association of Fire Chiefs, 2003). Thus, the reduction of problems in the relationship between the crew members increases their efficiency in extreme situations.
Aircraft design or airworthiness is the standard by which one determines whether an aircraft is suitable for the flight. Responsibility for airworthiness lies within the national aviation regulators, producers, owners, and operators. International Civil Aviation Organization establishes international standards and recommends practices to the national authorities on which they can base their rules. Aircraft manufacturers guarantee that the aircraft conforms to existing standards of design. The main goal and objective of airworthiness is to protect valuable cargo or passengers from injuries caused by the accident. In fact, aircraft stress pressurized fuselage skin provides this function. However, in the case of the nose or tail impact, the large bending moments built at the fuselage cause cracks in the shell, leading to the fuselage breaking to smaller pieces.
An aircraft is designed in a way that the interior of the cabin is equipped with safety features such as oxygen masks closed in luggage compartments so that in the case of fire or accident, one could use them. Moreover, there are belts for making sure one is tightened when sited to prevent body movements and life jackets to insure any risk is covered. Fuel valve handles link the valve mechanisms that are designed to minimize the possibility of incorrect installation. The tank is positioned in a strategic place that makes it possible to pass the selector to put OFF position at the transit from one container to another.
Currently, many innovative production technologies have been implemented, including advanced welding technologies, for example friction welding shuffle. Apparently, these modern technology changes eliminate the need for old or traditional rivets, which decrease aerodynamic drag, production costs of airplane in flight and material weight. Friction and lift-dependent drag are the largest contributors to air resistance. In fact, materials, design, and aerodynamics intend to reduce drag by maximizing the effective expansion of wingspan. Wingtip devices increase the effectiveness of aerodynamic wing span. According to International Civil Aviation Organization (2010), friction resistance is the main area that will be of potential aircraft’s aerodynamic efficiency improvement over the next ten to twenty years. Moreover, according to them, the possible approach to reduce friction is the application of Natural Laminar Flow (NLF) and Hybrid Laminar Flow Control (HLFC) on wings, nacelles and empennages (International Civil Aviation Organization, 2010).
Fuel System Improvements
Airplanes provide quick and reliable form of transportation at a long distance around the world. Over the years, technological advances have been made in the aircraft engines and the general aircraft body to make them more efficient. However, today’s aircrafts economize on more than fifteen percent of fuel in comparison with aircrafts a decade ago. Moreover, in the near future, airlines intend to provide uninterrupted flows of the contaminant-free fuel, regardless of the aircraft’s attitude. It is imperative to build a sufficiently strong airframe because of the aircraft’s weight while in flight (Federal Aviation Administration, 2012). Thus, varying fuel amount and changes in weight should not adversely affect the control of the aircraft in flight during maneuvers. In fact, engine security is important in relation to the safety of flights. Thus, fuel system improvements are as follows:
Fuel valves and controls. In modern aircrafts, there are means that allow members of the flight crew to appropriately and quickly turn off the fuel supply to each engine individually in the flight. The problem is that check valves are not on the engine side of any firewalls. Thus, there must be means of protection against accidental stop of each valve because to restore a valve means to prevent all valves from directing fuel to the engine. Consequently, each valve and fuel control system must be maintained so that loads arising from its engine operations were not moved to the lines connected to the valve (Federal Aviation Administration, 2012). Gravity force and vibration of the airplane should not have any effect on a selected position of the fuel valve. The reason is that fuel valve handles are connected to the valve mechanisms that are designed to reduce the probability of incorrect installation. The tank selector positioned in a strategic place makes it possible to pass the selector to take OFF position at the transit from one container to another.
Carburetor icing. When the fuel evaporates, it draws energy from the environment to change the state from liquid to vapor. However, when there is water, it can cause a problem. Thus, modern aircrafts are modified in a way that when fuel evaporates from the carburetor, water in the fuel-air mixture freezes it and deposits it inside the carburetor and fuel induction system. In some cases, ice prevents the movement of fuel and air in the fuel system and engine that causes loss of engine power and in severe cases, the engine stops working. Carburetor icing occurs at room temperature, and higher temperatures cause engine damage, especially in wet conditions. Most modern aircrafts are equipped with carburetor heat to help eliminate the threat caused by the high fugacity of the fuel and the presence of humidity (Federal Aviation Administration, 2012).
Conditions for fuel ignition are fuel vapor, air, and a source of fire. Thus, modern aircrafts are modified in a way that fuel or fuel system components are separated to prevent these elements from touching because they can provoke fire or explosion. The source of ignition is often the most controlled part. Also, the removal of all sources of ignition from the working area aims to protect them against static electricity that may cause fire. The action flows through the fuel consumption can cause static discharges like many other situations in which one object moves past another. Thus, pilots and mechanics should always assess the working area and take steps to eliminate any potential sources of static electricity ignition.
The combination of light weight and durability makes advanced composite materials very useful when creating an aircraft that is designed to fly fast and be subjected to physical exertion. On the other hand, the bulky equipment is needed when it comes to inspection of the aircraft for damage or a problem. Thus, new technology is a feasible solution due to the creation of a new advanced type of composite material which includes carbon nanotubes. Composites comprise the aircraft with high strength fibers such as carbon or glass embedded in plastic or metal matrix. Unlike aluminum, they do not have a homogeneous surface, which means that they can look fine on the outside despite the damage inside.
Composite materials have more advantage than aluminum because after hitting, they do not show damage to the surface even if there is internal structure damage. Currently, advanced composites can be checked using infrared thermography. Where materials are heated and if any area that is broken or the layers are separated, there is shown different redirection of heat that can be seen with a thermal imager. However, the problem of the aircraft surface heating requires bulky equipment that makes this method difficult. Thus, to solve this problem, experts have developed a novel composite material which can undergo the infrared thermograph without requiring an external heat source. Carbon nanotubes were included in the composite material, and when small electric current is applied to the surface of the nanotubes, they are heated. Thus, it means that an abnormal heat flux is clearly seen by the inspector through goggles provided with thermal and simple portable devices for supplying electric current.
Due to the nonlinearity and strong interactions between the components, the optimal total aircraft fails to provide the best solutions for each design component. Thus, the advantages of this component must be directly gained after its integration.