1.
Aircraft
–
An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the lift of an airfoil. The human activity that surrounds aircraft is called aviation, crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as type, aircraft propulsion, usage. Each of the two World Wars led to technical advances. Consequently, the history of aircraft can be divided into five eras, Pioneers of flight, first World War,1914 to 1918. Aviation between the World Wars,1918 to 1939, Second World War,1939 to 1945. Postwar era, also called the jet age,1945 to the present day, aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large gasbags or canopies, filled with a relatively low-density gas such as helium, hydrogen, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, a balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs – usually fixed-wing. In 1919 Frederick Handley Page was reported as referring to ships of the air, in the 1930s, large intercontinental flying boats were also sometimes referred to as ships of the air or flying-ships. – though none had yet been built, the advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by an outer framework and separate aerodynamic skin surrounding the gas bags, were produced. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a balloon is an aerostat and an airship is a powered one. A powered, steerable aerostat is called a dirigible, sometimes this term is applied only to non-rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship. Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back and these soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons, in windy weather
Aircraft
–
NASA test aircraft
Aircraft
–
The
Mil Mi-8 is the
most-produced helicopter in history
Aircraft
–
"Voodoo" a modified P 51 Mustang is the 2014 Reno Air Race Champion
Aircraft
–
A hot air
balloon in flight
2.
Aviator
–
A pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Other aircrew members such as attendants, mechanics and ground crew, are not classified as aviators. In recognition of the qualifications and responsibilities, most militaries and many airlines worldwide award aviator badges to their pilots. The first recorded use of the aviator was in 1887, as a variation of aviation, from the Latin avis. The term aviatrix, now archaic, was used for a female aviator. These terms were used more in the days of aviation, when airplanes were extremely rare. For example, a 1905 reference work described the Wright brothers first airplane, The weight, the Aéro-Club de France delivered the first certificate to Louis Blériot in 1908—followed by Glenn Curtiss, Léon Delagrange, and Robert Esnault-Pelterie. The absolute authority given to the pilot in command derives from that of a ships captain, when flying for an airline, pilots are usually referred to as airline pilots, with the pilot in command often referred to as the captain. While the flight decks of U. S. and European airliners do have ex-military pilots, military training and flying, while rigorous, is fundamentally different in many ways from civilian piloting. Pilots licensing in Canada is similar to the United States, the Aeronautics Act of 1985 and Canadian Aviation Regulations provide rules for pilots in Canada. Retirement age is provided by each airline with some set to age 60, in 1930, the Air Commerce Act established pilot licensing requirements for American civil aviation. Commercial airline pilots in the United States have a retirement age of 65. Military pilots fly with the forces of a government or nation-state. Their tasks involve combat and non-combat operations, including direct hostile engagements, military pilots undergo specialized training, often with weapons. Examples of military pilots include fighter pilots, bomber pilots, transport pilots, military pilots also serve as flight crews on aircraft for government personnel, such as Air Force One and Air Force Two in the United States. Military pilots are trained with a different syllabus than civilian pilots and this is due to the different aircraft, flight goals, flight situations and chains of responsibility. Many military pilots do transfer to civilian-pilot qualification after they leave the military, the person controlling a remotely piloted UAV may be referred to as its pilot or operator. Most jurisdictions have restrictions on the use of UAVs which have limited their use in controlled airspace, UAVs have mostly been limited to military
Aviator
–
U.S. Army test pilot
Lt. F.W. "Mike" Hunter wearing a
flight suit in October 1942
Aviator
–
Hot air balloon pilot and passenger in basket
Aviator
–
Pilots landing a
Boeing 777
Aviator
–
F-16 pilot in flight
3.
Underwater diving
–
Underwater diving is the practice of descending below the waters surface to conduct underwater activities. The saturation diving technique reduces the risk of decompression sickness after long duration deep dives, Atmospheric diving suits may be used to isolate the diver from the effects of high ambient pressure. Although not usually considered to be diving, crewed submersibles can extend depth range, Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable to the diver can vary considerably. Occasionally diving may be done in other than water. Recreational diving, sometimes called sport diving or subaquatics, is a leisure activity. Technical diving is a form of diving that achieves greater depths or endurance in more challenging conditions. Professional diving takes a range of diving activities to the work site. Public safety diving is the work done by law enforcement, fire rescue, and search & rescue/recovery dive teams. Military diving includes combat diving, clearance diving and ships husbandry diving, underwater sports is a group of competitive sports using either free-diving, snorkeling or scuba technique, or a combination of these techniques. The term deep sea diving refers to underwater diving, usually with surface supplied equipment, hard hat diving is any form of diving with a helmet, including the standard copper helmet, and other forms of free-flow and lightweight demand helmets. There are several modes of diving based on the equipment used. The ability to dive and swim underwater while holding ones breath is considered a useful skill, an important part of water sport and Navy safety training. Underwater diving without breathing apparatus can be categorized as underwater swimming, snorkeling and freediving. Several competitive underwater sports are practiced without breathing apparatus, freediving precludes the use of external breathing devices, and relies on the ability of divers to hold their breath until resurfacing. The technique ranges from simple breath-hold diving to competitive apnea dives, fins and a diving mask are often used in free diving to improve vision and provide more efficient propulsion. A short breathing tube called a snorkel allows the diver to breathe at the surface while the face is immersed, snorkeling on the surface with no intention of diving is a popular water sport and recreational activity. Scuba diving is diving with an underwater breathing apparatus, which is completely independent of surface supply. Scuba provides the diver with the advantages of mobility and horizontal range far beyond the reach of a hose attached to surface-supplied diving equipment
Underwater diving
–
A U.S. Navy diver enters the water during a training evaluation
Underwater diving
Underwater diving
–
Museum of Diving in
Warsaw
Underwater diving
–
Natural sponges have been harvested by free divers near the Greek island of
Kalymnos since at least the time of
Plato.
4.
Vestibular system
–
Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of the inner ear in most mammals, situated in the vestibulum in the inner ear. The vestibular system sends signals primarily to the structures that control eye movements. The brain uses information from the system in the head. The semicircular canal system detects rotational movements, the semicircular canals are its main tools to achieve this detection. Since the world is three-dimensional, the system contains three semicircular canals in each labyrinth. They are approximately orthogonal to other, and are called the horizontal, the anterior semicircular canal. Anterior and posterior canals may be collectively called vertical semicircular canals, movement of fluid within the horizontal semicircular canal corresponds to rotation of the head around a vertical axis, as when doing a pirouette. The anterior and posterior canals detect rotations of the head in the sagittal plane. Both anterior and posterior canals are orientated at approximately 45° between frontal and sagittal planes, each of these three pairs works in a push-pull fashion, when one canal is stimulated, its corresponding partner on the other side is inhibited, and vice versa. Vertical canals are coupled in a fashion, i. e. stimulations that are excitatory for an anterior canal are also inhibitory for the contralateral posterior. For example, when the head moves to the right, the move to the left. The VOR reflex does not depend on visual input and works even in darkness or when the eyes are closed. The mechanics of the canals can be described by a damped oscillator. For humans, the time constants T1 and T2 are approximately 3 ms and 5 s, as a result, for typical head movements, which cover the frequency range of 0.1 Hz and 10 Hz, the deflection of the cupula is approximately proportional to the head-velocity. This is very useful, since the velocity of the eyes must be opposite to the velocity of the head in order to have clear vision, signals from the vestibular system also project to the cerebellum and to different areas in the cortex. The projections to the cortex are spread out over different areas, the vestibular nuclei on either sides of the brain stem exchange signals regarding movement and body position. These signals are sent down the following projection pathways, signals sent to the cerebellum are relayed back as muscle movements of the head, eyes, and posture. To nuclei of cranial nerves III, IV, and VI, signals sent to these nerves cause the vestibulo-ocular reflex
Vestibular system
–
Figure 2: Push-pull system of the semicircular canals, for a horizontal head movement to the right.
5.
Visual flight
–
Visual flight rules are a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minima, i. e. in visual meteorological conditions, the pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft. If the weather is below VMC, pilots are required to use instrument flight rules, in a control zone, a VFR flight may obtain a clearance from air traffic control to operate as Special VFR. VFR require a pilot to be able to see outside the cockpit, to control the altitude, navigate. In some countries VFR flight is permitted at night, and is known as Night VFR, the VFR pilot is required to see and avoid obstacles and other aircraft. Pilots flying under VFR assume responsibility for their separation from all aircraft and are generally not assigned routes or altitudes by air traffic control. Meteorological conditions that meet the requirements for VFR flight are termed visual meteorological conditions. If they are not met, the conditions are considered instrument meteorological conditions, IFR operations have specific training requirements and certification required of the pilot, and increased equipment requirements for the aircraft. Additionally, an IFR flight plan must usually be filed in advance, for efficiency of operations, some ATC operations will routinely provide pop-up IFR clearances for aircraft operating VFR, but that are arriving at an airport that does not meet VMC requirements. For instance, a small cloud forming over the airport at less than 1000 feet technically requires the airport to allow only IFR flights using instrument approaches/departures. To avoid these scenarios, VFR flights intending to land at or take off from an airport experiencing localized conditions marginally below VMC minima may request Special VFR clearance from the tower. SVFR flight is only allowed while within the portion of an airports controlled airspace extends to the surface. Visibility on the ground must still be greater than one statute mile, the pilot is required to maintain VFR separation distances from other aircraft and, by requesting SVFR, asserts that they can do so despite the marginal conditions. For departing flights, the pilot must be flying in VMC by the time they leave the surface footprint of the controlled airspace. In the United States, class A airspace is measured using flight levels, and begins at FL180 up to FL600, in the United States, Canada and Australia, a pilot operating VFR outside Class B, C, D airspace can request Flight Following from ATC. This service is provided by ATC if workload permits it, but is an advisory service only, the responsibility for maintaining separation with other aircraft and proper navigation still remains with the pilot. In the United Kingdom, this is known as a Traffic Service, in other countries it is known as Flight Information Service. In the United States and Canada, any certified pilot who meets specific recency of experience criteria may operate an aircraft under VFR
Visual flight
–
Section of CVFR flight routes map of
Tel Aviv (
Israel) area. Flight altitude in each direction is notated in yellow arrow-box. Compulsory reporting points are marked with triangles and airports are marked by yellow circles.
6.
Instrument flight rules
–
Instrument flight rules is one of two sets of regulations governing all aspects of civil aviation aircraft operations, the other is visual flight rules. The U. S. IFR flight depends upon flying by reference to instruments in the flight deck and it is also a term used by pilots and controllers to indicate the type of flight plan an aircraft is flying, such as an IFR or VFR flight plan. To put instrument flight rules into context, an overview of visual flight rules is necessary. This is known as operating the aircraft under VFR, and is the most common mode of operation for small craft, thus, cloud ceiling and flight visibility are the most important variables for safe operations during all phases of flight. However, typical daytime VFR minimums for most airspace is 3 statute miles of visibility and a distance from clouds of 500 below,1,000 above. Flight conditions reported as equal to or greater than these VFR minimums are referred to as visual meteorological conditions, any aircraft operating under VFR must have the required equipment on board, as described in FAR Part 91.205. Visual flight rules are simpler than instrument flight rules, and require significantly less training. VFR provides a degree of freedom, allowing pilots to go where they want, when they want. Pilots are not required to file a plan, do not have to communicate with ATC. When operation of an aircraft under VFR is not safe, because the visual cues outside the aircraft are obscured by weather or darkness, instrument flight rules must be used instead. IFR permits an aircraft to operate in instrument meteorological conditions, which is any weather condition less than VMC. Use of instrument flight rules are required when flying in Class A airspace regardless of weather conditions. Class A airspace extends from 18,000 feet above sea level to flight level 600 above the contiguous 48 United States. Flight in Class A airspace requires pilots and aircraft to be instrument equipped and rated, Instrument pilots must meticulously evaluate weather, create a very detailed flight plan based around specific instrument departure, en route, and arrival procedures, and dispatch the flight. The distance by which an aircraft avoids obstacles or other aircraft is termed separation, the most important concept of IFR flying is that separation is maintained regardless of weather conditions. In controlled airspace, air traffic control separates IFR aircraft from obstacles and other aircraft using a flight clearance based on route, time, distance, speed, ATC monitors IFR flights on radar, or through aircraft position reports in areas where radar coverage is not available. Aircraft position reports are sent as voice radio transmissions, in the United States, a flight operating under IFR is required to provide position reports unless ATC advises a pilot that the plane is in radar contact. The pilot must resume position reports after ATC advises that radar contact has been lost, IFR flights in controlled airspace require an ATC clearance for each part of the flight
Instrument flight rules
–
IFR in between cloud layers in a
Cessna 172
Instrument flight rules
–
IFR flying with clouds below
7.
United States
–
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
United States
–
Native Americans meeting with Europeans, 1764
United States
–
Flag
United States
–
The signing of the
Mayflower Compact, 1620.
United States
–
The
Declaration of Independence: the
Committee of Five presenting their draft to the
Second Continental Congress in 1776
8.
NTSB
–
The National Transportation Safety Board is an independent U. S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on accidents and incidents, certain types of highway crashes, ship and marine accidents, pipeline incidents. When requested, the NTSB will assist the military and foreign governments with accident investigation, the NTSB is also in charge of investigating cases of hazardous materials releases that occur during transportation. The agency is based in Washington, D. C, as of December 2014, it has four regional offices located in Anchorage, Alaska, Denver, Colorado, Ashburn, Virginia, and Seattle, Washington. The agency also operates a training center at its Ashburn facility. The origin of the NTSB was in the Air Commerce Act of 1926, the USAs first independent Air Safety Board was established in 1938, it lasted only fourteen months. In 1940, this authority was transferred to the Civil Aeronautics Boards newly formed Bureau of Aviation Safety, in 1967, Congress created a separate cabinet-level Department of Transportation, which among other things established the Federal Aviation Administration as an agency under the DOT. At the same time, the NTSB was established as an independent agency which absorbed the Bureau of Aviation Safetys responsibilities. However, from 1967 to 1975, the NTSB reported to the DOT for administrative purposes, while conducting investigations into the Federal Aviation Administration, also a DOT agency. To avoid any conflict, Congress passed the Independent Safety Board Act, as of 2015, the NTSB has investigated over 140,000 aviation incidents and several thousand surface transportation incidents. Formally, the National Transportation Safety Board refers to a five-manager investigative board whose five members are nominated by the President, no more than three of the five members may be from the same political party. This board is authorized by Congress under Chapter 11, Title 49 of the United States Code to investigate civil aviation, highway, marine, pipeline, and railroad accidents and incidents. This five-member board is authorized to establish and manage separate sub-offices for highway, marine, aviation, railroad, pipeline, collectively, National Transportation Safety Board, the Safety Board or NTSB is used to refer to the entire investigative agency established and managed by this five-member board. As of December 2015, Christopher A. Hart is Chairman of the NTSB, the board also includes Robert L. Sumwalt and Earl F. Weener, and has one vacant seat. Based on the results of investigations within its jurisdiction, the NTSB issues formal safety recommendations to agencies, the NTSB considers safety recommendations to be its primary tool for preventing future civil transportation accidents. However, the NTSB does not have the authority to enforce its safety recommendations, the NTSB is the lead agency in the investigation of a civil transportation accident or incident within its sphere. The go team can have as few as 3-4 people or as many as a dozen, following the investigation, the agency may then choose to hold public hearings on the issue. Ultimately, it will publish a report which may include safety recommendations based on its findings
NTSB
–
NTSB headquarters
NTSB
–
Official seal and emblem
NTSB
NTSB
9.
Proprioceptive system
–
In humans, it is provided by proprioceptors in skeletal striated muscles and tendons and the fibrous capsules in joints. It is distinguished from exteroception, by which one perceives the world, and interoception, by which one perceives pain, hunger, etc. The brain integrates information from proprioception and from the system into its overall sense of body position, movement. The position-movement sensation was originally described in 1557 by Julius Caesar Scaliger as a sense of locomotion, much later, in 1826, Charles Bell expounded the idea of a muscle sense, which is credited as one of the first descriptions of physiologic feedback mechanisms. Bells idea was that commands are carried from the brain to the muscles, in 1889, Alfred Goldscheider suggested a classification of kinaesthesia into three types, muscle, tendon, and articular sensitivity. In 1906, Charles Scott Sherrington published a work that introduced the terms proprioception, interoception. The exteroceptors are the organs that provide information originating outside the body, such as the eyes, ears, mouth, the interoceptors provide information about the internal organs, and the proprioceptors provide information about movement derived from muscular, tendon, and articular sources. Primary endings of muscle spindles respond to the size of a length change and its speed. Secondary endings of muscle spindles detect changes in length. Essentially, muscle spindles are stretch receptors, a major component of proprioception is joint position sense, which is determined by measuring the accuracy of joint–angle replication. These involve an individuals ability to perceive the position of a joint without the aid of vision, often it is assumed that the ability of one of these aspects will be related to another, however, experimental evidence suggests there is no strong relation between these two aspects. This suggests that while these components may well be related in a cognitive manner, more recent work into the mechanism of ankle sprains suggests that the role of reflexes may be more limited due to their long latencies, as ankle sprain events occur in perhaps 100 ms or less. In accordance, a model has been proposed to include a component of proprioception. Kinesthesia is a key component in muscle memory and hand-eye coordination, the ability to swing a golf club or to catch a ball requires a finely tuned sense of the position of the joints. This sense needs to become automatic through training to enable a person to concentrate on other aspects of performance, the initiation of proprioception is the activation of a proprioreceptor in the periphery. There are specific receptors for this form of perception termed proprioreceptors, just as there are specific receptors for pressure, light, temperature, sound. Proprioreceptors are sometimes known as adequate stimuli receptors, TRPN, a member of the transient receptor potential family of ion channels, has been found to be responsible for proprioception in fruit flies, nematode worms, African clawed frogs, and zebrafish. Piezo2, a cation channel, has been shown to underlie the mechanosensitivity of proprioceptors in mice
Proprioceptive system
–
The
cerebellum is largely responsible for coordinating the unconscious aspects of proprioception.
10.
Centrifugal force
–
In Newtonian mechanics, the centrifugal force is an inertial force directed away from the axis of rotation that appears to act on all objects when viewed in a rotating reference frame. When they are analyzed in a coordinate system. The term has also been used for the force that is a reaction to a centripetal force. The centrifugal force is an outward force apparent in a reference frame. All measurements of position and velocity must be relative to some frame of reference. An inertial frame of reference is one that is not accelerating, the use of an inertial frame of reference, which will be the case for all elementary calculations, is often not explicitly stated but may generally be assumed unless stated otherwise. In terms of a frame of reference, the centrifugal force does not exist. All calculations can be performed using only Newtons laws of motion, in its current usage the term centrifugal force has no meaning in an inertial frame. In an inertial frame, an object that has no acting on it travels in a straight line. When measurements are made with respect to a reference frame, however. If it is desired to apply Newtons laws in the frame, it is necessary to introduce new, fictitious. Consider a stone being whirled round on a string, in a horizontal plane, the only real force acting on the stone in the horizontal plane is the tension in the string. There are no forces acting on the stone so there is a net force on the stone in the horizontal plane. In an inertial frame of reference, were it not for this net force acting on the stone, in order to keep the stone moving in a circular path, this force, known as the centripetal force, must be continuously applied to the stone. As soon as it is removed the stone moves in a straight line, in this inertial frame, the concept of centrifugal force is not required as all motion can be properly described using only real forces and Newtons laws of motion. In a frame of reference rotating with the stone around the axis as the stone. However, the tension in the string is still acting on the stone, if Newtons laws were applied in their usual form, the stone would accelerate in the direction of the net applied force, towards the axis of rotation, which it does not do. With this new the net force on the stone is zero, with the addition of this extra inertial or fictitious force Newtons laws can be applied in the rotating frame as if it were an inertial frame
Centrifugal force
–
The interface of two
immiscible liquids rotating around a vertical axis is an upward-opening circular paraboloid.
11.
Accelerometer
–
An accelerometer is a device that measures proper acceleration, proper acceleration is not the same as coordinate acceleration. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earths gravity, by contrast, accelerometers in free fall will measure zero. Accelerometers have multiple applications in industry and science, highly sensitive accelerometers are components of inertial navigation systems for aircraft and missiles. Accelerometers are used to detect and monitor vibration in rotating machinery, accelerometers are used in tablet computers and digital cameras so that images on screens are always displayed upright. Accelerometers are used in drones for flight stabilisation, coordinated accelerometers can be used to measure differences in proper acceleration, particularly gravity, over their separation in space, i. e. gradient of the gravitational field. This gravity gradiometry is useful because absolute gravity is a weak effect, micromachined accelerometers are increasingly present in portable electronic devices and video game controllers, to detect the position of the device or provide for game input. An accelerometer measures proper acceleration, which is the acceleration it experiences relative to freefall and is the acceleration felt by people and objects. Put another way, at any point in spacetime the equivalence principle guarantees the existence of an inertial frame. Such accelerations are popularly denoted g-force, i. e. in comparison to standard gravity, an accelerometer at rest relative to the Earths surface will indicate approximately 1 g upwards, because any point on the Earths surface is accelerating upwards relative to the local inertial frame. The reason for the appearance of an offset is Einsteins equivalence principle. For similar reasons, an accelerometer will read zero during any type of free fall and this includes use in a coasting spaceship in deep space far from any mass, a spaceship orbiting the Earth, an airplane in a parabolic zero-g arc, or any free-fall in vacuum. Another example is free-fall at a high altitude that atmospheric effects can be neglected. However this does not include a fall in air resistance produces drag forces that reduce the acceleration. At terminal velocity the accelerometer will indicate 1 g acceleration upwards, Acceleration is quantified in the SI unit metres per second per second, in the cgs unit gal, or popularly in terms of standard gravity. For the practical purpose of finding the acceleration of objects with respect to the Earth, such as for use in a navigation system. This can be obtained either by calibrating the device at rest, conceptually, an accelerometer behaves as a damped mass on a spring. When the accelerometer experiences an acceleration, the mass is displaced to the point that the spring is able to accelerate the mass at the rate as the casing. The displacement is measured to give the acceleration
Accelerometer
–
A depiction of an accelerometer designed at
Sandia National Laboratories
12.
Flight dynamics
–
Flight dynamics is the study of the performance, stability, and control of vehicles flying through the air or in outer space. It is concerned with how forces acting on the vehicle influence its speed, in fixed-wing aircraft, the changing orientation of the vehicle with respect to the local air flow is represented by two critical parameters, angle of attack and angle of sideslip. These angles describe the direction of airspeed, important because they are the principal source of modulations in the aerodynamic forces. Spacecraft flight dynamics involve three forces, propulsive, gravitational, and lift and drag, because aerodynamic forces involved with spacecraft flight are very small, this leaves gravity as the dominant force. These angles are the product of the equations of motion. For all flight vehicles, these two sets of dynamics, rotational and translational, operate simultaneously and in a fashion to evolve the vehicles state trajectory. This section focuses on fixed-wing aircraft, flight dynamics is the science of air-vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the center of mass, known as roll, pitch and yaw. Aircraft engineers develop control systems for a vehicles orientation about its center of mass, for example, a pitching moment is a vertical force applied at a distance forward or aft from the center of gravity of the aircraft, causing the aircraft to pitch up or down. Roll, pitch and yaw refer, in context, to rotations about the respective axes starting from a defined equilibrium state. The equilibrium roll angle is known as wings level or zero bank angle, a fixed-wing aircraft increases or decreases the lift generated by the wings when it pitches nose up or down by increasing or decreasing the angle of attack. The roll angle is known as bank angle on a fixed-wing aircraft. The forces acting on spacecraft are of three types, propulsive force, gravitational force exerted by the Earth and other celestial bodies, the vehicles attitude must be taken into account because of its effect on the aerodynamic and propulsive forces. There are other reasons, unrelated to flight dynamics, for controlling the attitude in non-powered flight. Also, most of a flight time is usually unpowered
Flight dynamics
–
Axes to control the attitude of a satellite
Flight dynamics
–
Axes to control the attitude of a plane
13.
Graveyard spiral
–
Other names for this phenomenon include suicide spiral, deadly spiral, death spiral and vicious spiral. Graveyard spirals are most common in nighttime or poor weather conditions where no horizon exists to provide correction for misleading inner-ear cues. In other words, the pilot loses the ability to judge the orientation of his due to the brain’s misperception of spatial cues. The graveyard spiral consists of physiological and physical components. Mechanical failure is often a result but generally not a causal factor, the pilot mistakenly believes they are flying with the wings level, but with a descent indicated on the altimeter and vertical speed indicator. This usually leads to the pulling up or attempting to climb by pulling back on the control yoke. In a banking turn, however, the airplane is at an angle, pulling back on the control yoke has the effect of tightening that circle and causing the airplane to lose altitude at an increasing rate, like water swirling in a drain or funnel. At that point the aircraft is describing a circle or spiral. In the ever-tightening, descending spiral the aircraft exits the base of the clouds and/or hits the ground. To avoid this situation, a student pilot or a pilot under instruction uses a view limiting device to learn instrument flying proficiency under the supervision of a flight instructor. Instrument-rated pilots also use view-limiting devices supervised by an instructor or a safety pilot to practise instrument flight, the inner ear contains the vestibular system, which is also known as the organ of equilibrium. Both the semicircular canals and the otolith organs provide information to the brain regarding the body’s position, a connection between the vestibular system and the eyes helps maintain balance and keep the eyes focused on an object while the head is moving or while the body is rotating. The semicircular canals are three half-circular, interconnected tubes located inside each ear that are the equivalent of three located in three planes perpendicular to each other. Each plane corresponds to the rolling, pitching, or yawing motions of an aircraft, each canal is filled with a fluid called endolymph and contains a motion sensor with hair-like protrusions whose ends are embedded in a gelatinous structure called the cupula. The cupula and the move as the fluid moves inside the canal in response to an angular acceleration. The movement of the hairs is similar to the movement of seaweed caused by currents or that of wheat fields moved by wind gusts. When the head is still and the airplane is straight and level, the fluid in the canals does not move, if you turn either your aircraft or your head, the canal moves with your head, but the fluid inside does not move because of its inertia. As the canal moves, the hairs inside also move with it and are bent in the direction of the acceleration by the stationary fluid
Graveyard spiral
–
Graveyard spiral
14.
G-force
–
The g-force is a measurement of the type of acceleration that causes a perception of weight. Despite the name, it is incorrect to consider g-force a fundamental force, since g-force accelerations indirectly produce weight, any g-force can be described as a weight per unit mass. The types of forces involved are transmitted through objects by interior mechanical stresses, the g-force acceleration is the cause of an objects acceleration in relation to free-fall. The g-force acceleration experienced by an object is due to the sum of all non-gravitational. In practice, as noted, these are surface-contact forces between objects, such forces cause stresses and strains on objects, since they must be transmitted from an object surface. Because of these strains, large g-forces may be destructive, gravitation acting alone does not produce a g-force, even though g-forces are expressed in multiples of the acceleration of a standard gravity. Thus, the gravitational acceleration at the Earths surface produces g-force only indirectly. These mechanical forces actually produce the g-force acceleration on a mass, for example, the 1 g force on an object sitting on the Earths surface is caused by mechanical force exerted in the upward direction by the ground, keeping the object from going into free-fall. The upward contact-force from the ground ensures that an object at rest on the Earths surface is accelerating relative to the free-fall condition, stress inside the object is ensured from the fact that the ground contact forces are transmitted only from the point of contact with the ground. Objects allowed to free-fall in an inertial trajectory under the influence of only, feel no g-force acceleration. This is demonstrated by the conditions inside a freely falling elevator falling toward the Earths center. These are examples of coordinate acceleration without a sensation of weight, the experience of no g-force, however it is produced, is synonymous with weightlessness. An example here is a rocket in space, in which simple changes in velocity are produced by the engines. The unit of measure of acceleration in the International System of Units is m/s2, however, to distinguish acceleration relative to free-fall from simple acceleration, the unit g is often used. One g is the due to gravity at the Earths surface and is the standard gravity, defined as 9.80665 metres per second squared. Note that the definition does not vary with location—the g-force when standing on the moon is about 0.181 g. The unit g is not one of the SI units, which uses g for gram, also g should not be confused with G, which is the standard symbol for the gravitational constant. For example, it is said an F-16 fighter jet is able to sustain up to 9 Gs for a limited time
G-force
–
This
top-fuel dragster can accelerate from zero to 160 kilometres per hour (99 mph) in 0.86 seconds. This is a horizontal acceleration of 5.3 g. Combined with the vertical g-force in the stationary case the
Pythagorean theorem yields a g force of 5.4 g.
G-force
–
In straight and level flight, lift (L) equals weight (W). In a banked turn of 60°, lift equals double the weight (L=2W). The pilot experiences 2 g and a doubled weight. The steeper the bank, the greater the G-Forces.
G-force
–
This
acrobatic airplane is pulling up in a +g maneuver; the pilot is experiencing several g's of inertial acceleration in addition to the force of gravity. The cumulative vertical axis forces acting upon his body make him momentarily 'weigh' many times more than normal.
G-force
–
John Stapp was subjected to 15 g for 0.6 seconds and a peak of 22 g during a 19 March 1954 rocket sled test. He would eventually survive a peak of more than 46 g, with more than 25 g for 1.1 seconds.
15.
Airframe
–
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage, airframe design is a field of aerospace engineering that combines aerodynamics, materials technology and manufacturing methods to achieve balances of performance, reliability and cost. Modern airframe history began in the United States when a 1903 wood biplane made by Orville, in 1912 the Deperdussin Monocoque pioneered the light, strong and streamlined monocoque fuselage formed of thin plywood layers over a circular frame, achieving 210 km/h. Many early developments were spurred by military needs during World War I and these used hybrid wood and metal structures. In 1916 the German Albatros D. German engineer Hugo Junkers first flew all-metal airframes in 1915 with the all-metal, cantilever-wing, commercial aircraft development during the 1920s and 1930s focused on monoplane designs using Radial engines. Some were produced as single copies or in small quantity such as the Spirit of St. Louis flown across the Atlantic by Charles Lindbergh in 1927, william Stout designed the all-metal Ford Trimotors in 1926. They were among the most successful designs to emerge from the era through the use of all-metal airframes, during World War II, military needs again dominated airframe designs. The first jets were produced during the war but not made in large quantity, postwar commercial airframe design focused on airliners, on turboprop engines, and then on Jet engines, turbojets and later turbofans. The generally higher speeds and tensile stresses of turboprops and jets were major challenges, Airbus and Boeing are the dominant assemblers of large jet airliners while ATR, Bombardier and Embraer lead the regional airliner market, many manufacturers produce airframe components. It has a carbon fiber fuselage, said to replace 1,200 sheets of aluminum and 40,000 rivets. In February 2017, Airbus installed a 3D printing machine for titanium aircraft structural parts using electron beam additive manufacturing from Sciaky, airframe production has become an exacting process. Manufacturers operate under strict quality control and government regulations, departures from established standards become objects of major concern. A landmark in aeronautical design, the worlds first jet airliner, early models suffered from catastrophic airframe metal fatigue, causing a series of widely publicised accidents. The Royal Aircraft Establishment investigation at Farnborough Airport founded the science of aircraft crash reconstruction, after 3000 pressurisation cycles in a specially constructed pressure chamber, airframe failure was found to be due to stress concentration, a consequence of the square shaped windows. The windows had been engineered to be glued and riveted, but had been punch riveted only, unlike drill riveting, the imperfect nature of the hole created by punch riveting may cause the start of fatigue cracks around the rivet. The Lockheed L-188 Electra turboprop, first flown in 1957 became a lesson in controlling oscillation. Its 1959 crash of Braniff Flight 542 showed the difficulties that the airframe industry, the A300 had experienced other structural problems but none of this magnitude. Longeron Former Chord Aircraft fairing Vertical stabilizer
Airframe
–
Airframe diagram for an
AgustaWestland AW101 helicopter
Airframe
–
DH106 Comet 3 G-ANLO demonstrating at the 1954
Farnborough Airshow
Airframe
–
Rough interior of a
Boeing 747 airframe
Airframe
–
Wing structure with
ribs and one
spar
16.
Sensory Illusions in Aviation
–
These illusions can be extremely dangerous for pilots. The vestibular system consists of the organs and the semicircular canals. Illusions in aviation are caused when the brain cannot reconcile the vestibular, stimulation of the semicircular canals occurs when movement of the endolymph inside the canals causes movement of the crista ampullaris and the hair cells within them. Stimulation of the otolith organs occurs when gravitational forces or linear accelerations cause movement of the membrane, the otoliths. Somatogyral illusions occur as a result of angular accelerations stimulating the semicircular canals, somatogravic illusions, on the other hand, occur as a result of linear accelerations stimulating the otolith organs. These include the leans, the spin and spiral. This is the most common illusion during flight, and can be caused by a return to wings-level flight following a gradual application of bank that had gone unnoticed by the pilot. Rolling wings-level from such an attitude may cause an illusion that the aircraft is banking in the opposite direction. In response to such an illusion, a pilot will tend to back in the direction of the original bank in a corrective attempt to regain the perception of a level attitude. The graveyard spin is an illusion that can occur to a pilot who enters a spin, for example, a pilot who enters a spin to the left will initially have a sensation of spinning in the same direction. However, if the spin continues the pilot will have the sensation that the spin is progressively decreasing. At this point, if the pilot applies right rudder to stop the left spin, if the pilot believes that the airplane is spinning to the right, the response will be to apply left rudder to counteract the sensation of a right spin. However, by applying left rudder the pilot will unknowingly re-enter the original left spin, if the pilot cross-checks the turn indicator, he would see the turn needle indicating a left turn while he senses a right turn. This creates a conflict between what the pilot sees on the instruments and what the pilot feels. If the pilot believes the body instead of trusting the instruments. If enough altitude is lost before this illusion is recognized and corrective action is not taken, the graveyard spiral is more common than the graveyard spin, and it is associated with a return to level flight following a prolonged bank turn. For example, a pilot who enters a turn to the left will initially have a sensation of a turn in the same direction. If the left turn continues, the pilot will experience the sensation that the airplane is no longer turning to the left
Sensory Illusions in Aviation
–
Blind flying. The pilot wears goggles blocking the colors transparent through the orange plastic sheet in front of him. The
instructor wearing no goggles has an outside view tinted orange.
17.
Equivalence principle
–
Kepler, using Galileos discoveries, showed knowledge of the equivalence principle by accurately describing what would occur if the moon were stopped in its orbit and dropped towards Earth. This can be deduced without knowing if or in what manner gravity decreases with distance, the 1/54 ratio is Keplers estimate of the Moon–Earth mass ratio, based on their diameters. The accuracy of his statement can be deduced by using Newtons inertia law F=ma, setting these accelerations equal for a mass is the equivalence principle. Einstein stated it thus, we assume the physical equivalence of a gravitational field. That is, being on the surface of the Earth is equivalent to being inside a spaceship that is being accelerated by its engines, from this principle, Einstein deduced that free-fall is inertial motion. Objects in free-fall do not experience being accelerated downward but rather weightlessness, in an inertial frame of reference bodies obey Newtons first law, moving at constant velocity in straight lines. Analogously, in a curved spacetime the world line of a particle or pulse of light is as straight as possible. Such a world line is called a geodesic and from the point of view of the frame is a straight line. This is why an accelerometer in free-fall doesnt register any acceleration, as an example, an inertial body moving along a geodesic through space can be trapped into an orbit around a large gravitational mass without ever experiencing acceleration. This is possible because spacetime is curved in close vicinity to a large gravitational mass. In such a situation the geodesic lines bend inward around the center of the mass, an accelerometer on-board would never record any acceleration. By contrast, in Newtonian mechanics, gravity is assumed to be a force and this force draws objects having mass towards the center of any massive body. At the Earths surface, the force of gravity is counteracted by the resistance of the Earths surface. So in Newtonian physics, a person at rest on the surface of an object is in an inertial frame of reference. Einstein also referred to two frames, K and K. This observation was the start of a process that culminated in general relativity, by assuming this to be so, we arrive at a principle which, if it is really true, has great heuristic importance. So the original equivalence principle, as described by Einstein, concluded that free-fall and this form of the equivalence principle can be stated as follows. An observer in a windowless room cannot distinguish between being on the surface of the Earth, and being in a spaceship in deep space accelerating at 1g
Equivalence principle
–
General relativity
18.
General relativity
–
General relativity is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity generalizes special relativity and Newtons law of gravitation, providing a unified description of gravity as a geometric property of space and time. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter, the relation is specified by the Einstein field equations, a system of partial differential equations. Examples of such differences include gravitational time dilation, gravitational lensing, the redshift of light. The predictions of relativity have been confirmed in all observations. Although general relativity is not the only theory of gravity. Einsteins theory has important astrophysical implications, for example, it implies the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. The bending of light by gravity can lead to the phenomenon of gravitational lensing, General relativity also predicts the existence of gravitational waves, which have since been observed directly by physics collaboration LIGO. In addition, general relativity is the basis of current cosmological models of an expanding universe. Soon after publishing the special theory of relativity in 1905, Einstein started thinking about how to incorporate gravity into his new relativistic framework. In 1907, beginning with a thought experiment involving an observer in free fall. After numerous detours and false starts, his work culminated in the presentation to the Prussian Academy of Science in November 1915 of what are now known as the Einstein field equations. These equations specify how the geometry of space and time is influenced by whatever matter and radiation are present, the Einstein field equations are nonlinear and very difficult to solve. Einstein used approximation methods in working out initial predictions of the theory, but as early as 1916, the astrophysicist Karl Schwarzschild found the first non-trivial exact solution to the Einstein field equations, the Schwarzschild metric. This solution laid the groundwork for the description of the stages of gravitational collapse. In 1917, Einstein applied his theory to the universe as a whole, in line with contemporary thinking, he assumed a static universe, adding a new parameter to his original field equations—the cosmological constant—to match that observational presumption. By 1929, however, the work of Hubble and others had shown that our universe is expanding and this is readily described by the expanding cosmological solutions found by Friedmann in 1922, which do not require a cosmological constant. Lemaître used these solutions to formulate the earliest version of the Big Bang models, in which our universe has evolved from an extremely hot, Einstein later declared the cosmological constant the biggest blunder of his life
General relativity
–
A simulated
black hole of 10
solar masses within the
Milky Way, seen from a distance of 600 kilometers.
General relativity
–
Albert Einstein developed the theories of special and general relativity. Picture from 1921.
General relativity
–
Einstein cross: four images of the same astronomical object, produced by a
gravitational lens
General relativity
–
Artist's impression of the space-borne gravitational wave detector
LISA
19.
John F. Kennedy, Jr.
–
John Fitzgerald Kennedy Jr. often referred to as JFK Jr. or John John, was an American lawyer, journalist, and magazine publisher. He was the surviving son of former President John F. Kennedy and First Lady Jacqueline Kennedy. His father was assassinated three days before his third birthday, from his early childhood onwards, Kennedy was the subject of great media scrutiny, and he became a popular social figure of Manhattan. Trained as a lawyer, he worked as a New York City Assistant District Attorney for four years, in 1995, he launched George magazine, using his political and celebrity status to publicize it. Kennedy died along with his wife Carolyn Bessette-Kennedy and her elder sister Lauren in the crash of a plane he was piloting. Kennedy had intended to drop off Lauren at Marthas Vineyard before continuing to the wedding of his cousin Rory Kennedy in Hyannis Port, John Fitzgerald Kennedy Jr. was born at Georgetown University Hospital on November 25,1960, two weeks after his father was elected president. His parents had a daughter named Arabella four years before John Jr. s birth. John Jr. had a sister, Caroline, and an infant brother, Patrick. His putative nickname, John-John, came from a reporter who misheard JFK calling him John twice in quick succession, John Jr. lived in the White House during the first three years of his life, and later remained in the public spotlight up until his death. His father was assassinated on November 22,1963, and the funeral was held three days later on John Jr. s third birthday. In a moment that became an image of the 1960s, John Jr. stepped forward. The family continued with their plans for a party, to demonstrate that the Kennedys would go on despite the death of their father. Following his fathers assassination, Kennedy moved to the Upper East Side of Manhattan in New York City with his mother and sister, where he grew up. In 1967, his mother took him and his sister Caroline on a sentimental journey to Ireland. After his uncle Robert was assassinated in 1968, his mother took him and his out of the United States, saying, If theyre killing Kennedys. I want to get out of this country, the same year, she married Greek shipping tycoon Aristotle Onassis, and the family went to live on his private island of Skorpios. Kennedy is said to have considered his stepfather a joke, in 1971, Kennedy returned to the White House with his mother and sister for the first time since the assassination. President Richard Nixons daughters gave Kennedy a tour that included his old bedroom, when Onassis died in 1975, he left Kennedy $25,000, though Jacqueline was able to renegotiate the will, and acquired $20 million for herself and her children
John F. Kennedy, Jr.
–
Kennedy greets invited guests at the
HBO and
Imagine Entertainment premiere held at the
Kennedy Space Center in 1998.
John F. Kennedy, Jr.
–
JFK Jr. at age two, with his father at the
White House
John F. Kennedy, Jr.
–
Family
20.
John F. Kennedy, Jr. airplane crash
–
On July 16,1999, John F. Kennedy Jr. died when the airplane he was piloting crashed into the Atlantic Ocean off the coast of Marthas Vineyard, Massachusetts. The two passengers on board, Kennedys wife Carolyn Bessette and her sister Lauren, were also killed, Kennedy did not hold an instrument rating and was therefore only certified to fly under visual flight rules. However, at the time of the accident the weather and light conditions were such that all basic landmarks were obscured, making visual flight challenging, although legally still permissible. On the evening of July 16,1999, John F. Kennedy Jr. piloted a Piper Saratoga to attend the wedding of his cousin Rory Kennedy, the plane also carried his wife, Carolyn Bessette, and sister-in-law, Lauren Bessette. Kennedy had purchased his plane three months before his death, the Bessette sisters were seated in the second row of seats, which faced the rear of the plane and were back-to-back with the pilots seat. Kennedy checked in with the air control tower of Marthas Vineyard Airport before departure. At 8,39 p. m. on July 16, at 2,15 a. m. the next day, the Kennedy family reported to the local Coast Guard Air Station that the plane had not arrived. At 4 a. m, the U. S. Coast Guard began a search, Kennedys cousin, Anthony Stanislas Radziwill, told the press that if Kennedy was still alive hell find a way to get out. He possesses the will to survive, enough will for all three of them, officials were not optimistic about finding Kennedy alive after several pieces of debris from his plane were recovered in the Atlantic Ocean. There is always hope, Coast Guard Lt. Gary Jones said on July 17, but unfortunately, when you find certain pieces of evidence, you have to be prepared for anything. That same day, President Bill Clinton spoke with Kennedys older sister, Caroline, Clinton also spoke with Andrew Cuomo, who at the time was married to Kennedys cousin, Kerry. He wanted to let them know he was thinking about them, that well do everything we can, Clinton ordered warships of the U. S. Navy to assist in the search for Kennedys plane. Critics argued that this was an abuse of taxpayer dollars, as no ordinary citizen would receive similar treatment, Clinton said that afternoon that the Kennedys had suffered much, and given more. He also called for the Kennedys to feel the strength of God, the love of their friends, on July 19, NOAA vessel Rude located fragments of Kennedys plane using side-scan sonar. The Rude captured high-resolution images which were used to create a map of the ocean floor. At 11,30 p. m. the next day, Navy divers found parts of the plane strewn over a broad area of seabed 120 feet below the surface. Late on the afternoon of July 21, the recovered the bodies of Kennedy. Divers found Carolyns and Laurens bodies near the fuselage, while Kennedys body was still strapped in the pilots seat, Coast Guard Admiral Richard M. Larrabee said that all three bodies were near and under the fuselage, still strapped in
John F. Kennedy, Jr. airplane crash
–
A
Piper Saratoga similar to N9253N, the aircraft flown by
John F. Kennedy Jr. on the night of the accident
21.
Night
–
Night or nighttime is the period of time between the sunset and the sunrise when the Sun is below the horizon. Complete darkness or astronomical night is the period of time between astronomical dusk and astronomical dawn when the sun is between 18 and 90 degrees below the horizon and the sky is totally dark, at latitudes between 48.5 and 66. The opposite of night is day, the start and end points of time for a night vary, based on factors such as season, latitude, longitude and timezone. Twilight is the time of night when the sky is illuminated by the sun but the sun is below the horizon. At any given time, one side of the planet Earth is bathed in light from the Sun and this shadow is called the umbra. Natural illumination is provided by a combination of moonlight, planetary light, starlight, diffuse zodiacal light, gegenschein. In some circumstances, bioluminescence, aurorae, and lightning can provide some illumination, the glow provided by artificial illumination is sometimes referred to as light pollution because it can interfere with observational astronomy and ecosystems. Nights are shorter than days on average due to two factors, firstly, the sun is not a point, but has an apparent size of about 32 arc minutes. Secondly, the atmosphere refracts sunlight so that some of it reaches the ground when the sun is below the horizon by about 34 arc minutes. The combination of two factors means that light reaches the ground when the center of the sun is below the horizon by about 50 arc minutes. Without these effects, day and night would be the length at the autumnal and vernal equinoxes. In reality, around the equinoxes the day is almost 14 minutes longer than the night at the equator, the summer and winter solstices mark the shortest and the longest night, respectively. The closer a location is to either the North Pole or the South Pole, in the Northern Hemisphere, Denmark has shorter nights in June than India. In the Southern Hemisphere, Antarctica has longer nights in June than Chile, the phenomenon of day and night is due to the rotation of a celestial body about its axis, creating an illusion of the sun rising and setting. Different bodies spin at different rates, however. Some may spin much faster than Earth, while others spin extremely slowly, leading to long days. The planet Venus rotates once every 224.7 days – by far the slowest rotation period of any of the major planets, in contrast, the gas giant Jupiters sidereal day is only 9 hours and 56 minutes. Mercury has the longest day-night cycle as a result of its 3,2 resonance between its orbital period and rotation period - this resonance gives it a day-night cycle 176 days long
Night
–
The
Nile River Delta at night
Night
–
Waning moon
Night
–
Nótt, the personification of night in
Norse mythology, rides her horse in this 19th-century painting by
Peter Nicolai Arbo.
22.
Jim Reeves
–
James Travis Jim Reeves was an American country and popular music singer-songwriter. With records charting from the 1950s to the 1980s, he well known as a practitioner of the Nashville sound. Known as Gentleman Jim, his songs continued to chart for years after his death, Reeves died in the crash of his private airplane. He is a member of both the Country Music and Texas Country Music Halls of Fame, Reeves was born at home in Galloway, Texas, a small rural community near Carthage. He was the youngest of 8 children born to Mary Beulah Adams Reeves and he was known as Travis during his childhood years. Winning an athletic scholarship to the University of Texas, he enrolled to study speech and drama, soon he resumed baseball, playing in the semi-professional leagues before contracting with the St. Louis Cardinals farm team during 1944 as a right-handed pitcher. He played for the leagues for three years before severing his sciatic nerve while pitching, which ended his athletic career. Reeves initial efforts to pursue a career were sporadic, possibly due to his uncertainty as to whether he would be drafted into the military as World War II enveloped the United States. On 9 March 1943 he reported to the Army Induction Center in Tyler for his physical examination. However, he failed the exam, and on 4 August 1943 an official letter declared his 4-F draft status, Reeves began to work as a radio announcer, and sang live between songs. During the late 1940s, he was contracted with a couple of small Texas-based recording companies and he eventually obtained a job as an announcer for KWKH-AM in Shreveport, Louisiana, then the home of the popular radio program the Louisiana Hayride. Jim Reeves was a country singer who had success early on in his career with hits such as I Love You, Mexican Joe. In addition to early hits, Reeves recorded many other songs for Fabor Records. In 1954, Abbott Records released a 45 single with Bimbo on side-A which hit #1, Jim Reeves and Little Joe Hunt met at the Louisiana Hayride which was Louisianas equivalent to Nashvilles Grand Ole Opry. After performing at the Hayride in Shreveport, Louisiana, Reeves and Hunt traveled & performed together for years in the dance halls and clubs of east Texas. Reeves became the headliner with Hunt as the backup performer, due to his growing popularity, Reeves went on to release his first album in November 1955, Jim Reeves Sings, which proved to be one of Abbott Records couple album releases. Reeves star was on the rise because he had already signed to a 10-year recording contract with RCA Victor by Steve Sholes. Sholes went on to some of Reeves first recordings at RCA Victor
Jim Reeves
–
Jim Reeves
Jim Reeves
–
Jim Reeves Drive at the
Texas Country Music Hall of Fame in
Carthage, Texas
23.
Buddy Holly
–
Buddy Holly was an American musician and singer-songwriter who was a central figure of mid-1950s rock and roll. Holly was born in Lubbock, Texas, to a family during the Great Depression, he learned to play guitar. His style was influenced by music, country music, and rhythm and blues acts. He made his first appearance on television in 1952. In 1955, after opening for Elvis Presley, Holly decided to pursue a career in music and he opened for Presley three times that year, his bands style shifted from country and western to entirely rock and roll. In October that year, when he opened for Bill Haley & His Comets, Holly was spotted by Nashville scout Eddie Crandall, Hollys recording sessions at Decca were produced by Owen Bradley. Petty became the manager and sent the demo to Brunswick Records, which released it as a single credited to The Crickets. In September 1957, as the band toured, Thatll Be the Day topped the US Best Sellers in Stores chart and its success was followed in October by another major hit, Peggy Sue. The album Chirping Crickets, released in November 1957, reached five on the UK Albums Chart. Holly made his appearance on The Ed Sullivan Show in January 1958 and soon after, toured Australia. In early 1959, Holly assembled a new band, consisting of country music star Waylon Jennings, famed session musician Tommy Allsup, and Carl Bunch. After a show in Clear Lake, Iowa, Holly chartered an airplane to travel to his show, in Moorhead. Soon after takeoff, the crashed, killing Holly, Ritchie Valens, The Big Bopper. During his short career, Holly wrote, recorded, and produced his own material and he is often regarded as the artist who defined the traditional rock-and-roll lineup of two guitars, bass, and drums. Holly was an influence on later popular music artists, including The Beatles, The Rolling Stones, Eric Clapton. He was among the first artists inducted into the Rock and Roll Hall of Fame, Rolling Stone Magazine ranked him number 13 in its list of 100 Greatest Artists. Buddy Holly was born Charles Hardin Holley on September 7,1936, in Lubbock, Texas, at 3,30 pm, he was the child of Lawrence Odell L. O. Holley. His older siblings were Larry, Travis, and Patricia Lou, from early childhood, he was nicknamed Buddy
Buddy Holly
–
Buddy Holly in 1957
Buddy Holly
–
Buddy Holly and the Crickets in 1957 (top to bottom: Allison, Holly and Mauldin)
Buddy Holly
–
Signpost near the Clear Lake crash site
Buddy Holly
–
Holly's headstone in the City of Lubbock Cemetery
24.
The Day the Music Died
–
On February 3,1959, rock and roll musicians Buddy Holly, Ritchie Valens, and J. P. The Big Bopper Richardson were killed in a crash near Clear Lake, Iowa. The event later known as The Day the Music Died. At the time, Holly and his band, consisting of Waylon Jennings, Tommy Allsup, rising artists Valens and Richardson had joined the tour, as well. The long journeys between venues on board the cold, uncomfortable tour buses adversely affected the performers, with cases of flu and even frostbite. After stopping at Clear Lake to perform, and frustrated by such conditions, Holly decided to charter a plane to reach their next venue in Moorhead, Minnesota. Richardson, who had the flu, swapped places with Jennings, taking his seat on the plane, the event has since been mentioned in various songs and films. A number of monuments have been erected at the site and in Clear Lake, where an annual memorial concert is also held at the Surf Ballroom. Buddy Holly terminated his association with the Crickets in November 1958, for the start of the Winter Dance Party tour, he assembled a band consisting of Waylon Jennings, Tommy Allsup, and Carl Bunch, with the opening vocals of Frankie Sardo. The tour was set to cover 24 Midwestern cities in as many days, New hit artist Ritchie Valens, J. P. The Big Bopper Richardson and Dion DiMucci and his band The Belmonts joined the tour to promote their recordings, the tour began in Milwaukee, Wisconsin, on January 23,1959. The amount of travel became a logistical problem. It was like they threw darts at a map, the tour from hell -- thats what they named it -- and its not a bad name. Griggs estimates that five separate buses were used in the first 11 days of the tour -- reconditioned school buses, the artists themselves were responsible for loading and unloading equipment at each stop, as no road crew assisted them. Adding to the disarray, the buses were not equipped for the weather which consisted of waist-deep snow in several areas, one bus had a heating system that broke down shortly after the tour began, in Appleton, Wisconsin. The musicians replaced that bus with another bus and kept traveling. After Bunch was hospitalized, Carlo Mastrangelo of The Belmonts took over the drumming duties, when Dion and The Belmonts were performing, the drum seat was taken by either Valens or Buddy Holly. As Hollys group had been the band for all of the acts, Holly, Valens, and DiMucci took turns playing drums for each other at the performances in Green Bay, Wisconsin
The Day the Music Died
–
The memorial marking the crash site, 2003
The Day the Music Died
–
A V-tailed
Bonanza similar to N3794N, the accident aircraft
The Day the Music Died
–
The wreckage of N3794N as found by the authorities on the morning of the accident
The Day the Music Died
–
Signpost near the Clear Lake crash site
25.
Patsy Cline
–
Patsy Cline was an American country music singer. Part of the late 1950s/early 1960s Nashville sound, Cline successfully crossed over to pop music and was one of the most influential, successful and she died at the age of 30 in a multiple-fatality crash of the private plane of her manager, Randy Hughes. Cline was known for her tone, emotionally expressive and bold contralto voice. Along with Kitty Wells, she helped pave the way for women as performers in the genre. Books, movies, documentaries, articles and stage plays document her life, millions of her records have sold since her death. She won awards and accolades, causing many to view her as an icon at the level of Jim Reeves, Johnny Cash, in 1973, ten years after her death, she became the first female solo artist inducted into the Country Music Hall of Fame. In 1999, she was voted number 11 on VH1s special, The 100 Greatest Women in Rock and Roll, by members, according to her 1973 Country Music Hall of Fame plaque, Her heritage of timeless recordings is testimony to her artistic capacity. She was born Virginia Patterson Hensley on September 8,1932, in Winchester, Virginia and she was the eldest child of seamstress Hilda Virginia and blacksmith Samuel Lawrence Hensley. She soon had a brother and sister, Samuel Jr. They were known in the family as Ginny, John, the family moved often before finally settling in Winchester, Virginia, when Patsy was eight. Sam Hensley deserted his family in 1947, but the home was reportedly happy nonetheless. Cline was introduced to music at an age, singing in church with her mother. She liked stars such as Kay Starr, Jo Stafford, Hank Williams, Judy Garland, self-taught, she could not read music. When Patsy was thirteen, she was hospitalized with a throat infection, the fever affected my throat and when I recovered I had this booming voice like Kate Smith. After watching performers through the window at the radio station, she asked WINC disc jockey. Her performance in 1947 was well received, and she was asked back and this led to appearances at local nightclubs, wearing fringed Western outfits her mother made from Patsys designs. Cline performed in variety and talent shows in the Winchester and Tri-State areas, along with this and increasing local radio appearances on local radio, she gained a large following. In 1954 Jimmy Dean, already a young star, heard of her
Patsy Cline
–
Patsy Cline at
4 Star Records in March 1957
Patsy Cline
–
Cline's home in Winchester, Virginia. She lived here from age 16 to 21.
Patsy Cline
–
Cline promotional photograph shortly before her 1961 life-threatening car accident
Patsy Cline
–
Patsy Cline aircraft crash site, Camden, Tennessee
26.
TaleSpin
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The name of the show is a play on tailspin, the rapid descent of an aircraft in a steep spiral. The two words in the name, tale and spin, are a way to describe telling a story. The series was developed by writers Jymn Magon and Mark Zaslove. There were four teams, each one headed by a producer/director, Robert Taylor, Larry Latham, Jamie Mitchell. Initially, Disney simply commissioned Magon and Zaslove with creating an animated program for them. The pair then decided to have Baloo work for an air delivery service, the decision to add Shere Khan to the cast was not made until later in the shows development. Magon and Zaslove also took inspiration from Hayao Miyazakis 1989 manga Hikōtei Jidai, about a man who flies a seaplane. Two years after TaleSpin premiered, Miyazaki released an adaptation called Porco Rosso. Famed Uncle Scrooge comic writer and artist Don Rosa wrote episode 6, It Came from Beneath the Sea Duck, and episode 9, I Only Have Ice for You. After a preview of TaleSpin aired on The Disney Channel from May 5 to July 15,1990, the original concept was embodied in the pilot episode and introductory television movie Plunder & Lightning which was the sole nominee for an Emmy Award for Outstanding Animated Program in 1991. After its premiere on September 7,1990, Plunder & Lightning was re-edited into four episodes for reruns. The show was seen either on its own as a half-hour show. TaleSpin ended on its 65th episode which aired on August 8,1991, however, reruns continued to be shown on The Disney Afternoon until September 1994. Later, the show was aired on Toon Disney, where it was first aired from April 1998 until January 2006, throughout its broadcast history, the series has been subjected to numerous edits. TaleSpin is set in the city of Cape Suzette, in a fictional country called Usland. The city lies in a protected by an enormous natural cliff wall. A single cleft in the wall is the only means of access. The cleft is guarded by artillery, preventing flying rabble-rousers or air pirates from entering the city
TaleSpin
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TaleSpin 's intertitle
27.
Adam Air Flight 574
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A national investigation was launched into the disaster. It was the fatal accident for Adam Air in the 5-year history of the company. Adam Air was subsequently banned from flying by the Indonesian government, the aircraft involved, Boeing 737-4Q8 serial number 24070, registration PK-KKW, was manufactured in 1989. Prior to service with Adam Air, owned by ILFC the aircraft had been leased to seven airlines, Dan-Air, British Airways, GB Airways, Transaero, WFBN, Air One and Jat Airways. The plane had around 50,000 hours flying and was last evaluated and declared airworthy by the Indonesian transport ministry on 25 December 2005 and it was due to be checked again in late January 2007. The Surabaya airport duty manager said that there were no problems with the aircraft prior to departure. The captain was 47-year-old Refri Agustian Widodo from Sidoarjo, Indonesia, the first officer was 36-year-old Yoga Susanto, an employee of Adam Air since 2006. Captain Widodo, a veteran, had logged more than 13,300 hours of flying time. As pilot-in-command of Boeing 737 aircraft, he had more than 3,800 hours of experience, first Officer Susanto had 4,200 total flying hours and he had almost 1,000 hours logged as a Boeing 737 first officer. On 1 January 2007, at 12,59 local time, the passenger list was composed mainly of Indonesian nationals, the only foreigners were an American family of three. The last known position was detected by a Singaporean satellite. The altitude of the plane was shown as 35,000 feet on the radar screen, although the Juanda Airport operator, PT Angkasa Pura I, had given warnings to the pilot concerning the weather condition, the plane had departed as scheduled. The plane ran into crosswinds of more than 70 knots over the Makassar Strait, west of Sulawesi, no calls for help were sent by the aircraft. Initial reports indicated that the plane had been located in the region of Sulawesi around 20 kilometres from Polewali town. This led to the mobilisation of an Indonesian Air Force plane carrying hundreds of search, however the team found no sign of aircraft wreckage at the reported crash site. It later turned out that the 12 reported survivors were actually from the MV Senopati Nusantara, a search and rescue team 3,600 members strong was mobilised. The Indonesian sonar-equipped ship Pulau Rengat, capable of detecting underwater metallic objects later joined the team and it searched the sea for five days between 3 and 8 January, without success. Naval ships combed the Makassar Strait while military personnel went through jungles, the search in the two areas was due to twin signals, each carrying different emergency locator transmitter frequencies, received by the Singaporean satellite and an Indonesian military air base
Adam Air Flight 574
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The accident aircraft when operated by JAT
Adam Air Flight 574
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Flight Route
28.
Aeroflot Flight 821
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Aeroflot Flight 821, operated by Aeroflot-Nord in a service agreement with Aeroflot and as its subsidiary, crashed on approach to Perm International Airport on 14 September 2008 at 5,10 local time. All 82 passengers and 6 crew members were killed, a section of the Trans-Siberian Railway was damaged by the crash. The primary cause of the crash was that pilots had lost spatial orientation due to their inexperience with the Western type of attitude indicator on the aircraft. Lack of adequate rest, poor CRM and alcohol consumption by the captain also contributed to the accident and this air disaster resulted in the rebranding of Aeroflot-Nord into Nordavia, effective on 1 December 2009. The weather at the time of accident was rainy, however, the crew reported no emergency onboard and confirmed all commands given by ATC. At 5,10 AM, radio contact with the plane was lost, Aeroflot-Nord officially stated that, The Boeing-737 carried 82 passengers on board — including 7 children — and 6 crew. As the plane was coming in for landing, it lost communication at the height of 1,100 metres, the airplane was found within Perms city limits completely destroyed and on fire. RIA Novosti however reported that it was possible that 3 people who bought a ticket for the ill-fated flight 821 to Perm did not get on board, both flight recorders were found and successfully decoded. The airline stated it pledged to pay compensation on obligatory accident insurance in full, the crash damaged and shut down a section of the Trans-Siberian Railway, rail traffic was temporarily re-routed via Chusovaya station, and was restored by the evening of 14 September. The aircraft was leased by Aeroflot-Nord from Dublin-based Pinewatch Limited from July 2008 to March 2013 and it was reported that its engines caught fire at an altitude of 1,000 metres. Eyewitness reports stated that the plane was visibly on fire prior to crashing, however, the low clouds must have prevented any witnesses from seeing the plane for more than a few seconds and the report was subsequently discounted by the accident enquiry. Aeroflot-Nord then leased the aircraft from Pinewatch Limited, and had operated the airframe from 29 May 2008 until its hull loss, the AAIB team had representatives from the Bermudian Department of Civil Aviation as advisors. The engines were made in France, so that state was represented by the Bureau dEnquêtes et dAnalyses pour la sécurité de lAviation Civile, According to the data in flight recorders, the engines did not catch fire and continued working until the impact. The latest official reports are published in Russian on the Air Accident Investigation Commission website, an English translation of the final report is available at the United Kingdom Air Accidents Investigation Branch website, the AAIB states that it is not an official English translation. The plane banked left, overturned and went into a rapid descent, the loss of spatial orientation occurred in the night, while flying in the clouds, with autopilot and autothrottle switched off. Poor CRM and insufficient training for using the Western type of attitude indicators contributed to the accident, the pilots had previously flown Tupolev Tu-134 and Antonov An-24 with a different type of attitude indicator. Inadequate practices by Aeroflot-Nord in managing and operating the Boeing 737 aircraft, the aircraft had been flown for a long time with a throttle problem. The pilots had a higher workload because they had to operate the throttle levers for the left, forensic examination found an unspecified amount of alcohol in the captains tissue
Aeroflot Flight 821
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The Aeroflot-Nord Boeing 737-500 that crashed (VP-BKO)
29.
Agni Air Flight 101
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Agni Air Flight 101 was a regional flight operated by Agni Air between Kathmandu, Nepal, and Lukla, Nepal, that crashed on 24 August 2010, killing all 14 people on board. Five minutes after this contact with the aircraft was lost. Initial reports suggested the crash had caused by a combination of severe weather. The investigation into the accident, however, found the cause was spatial disorientation following the loss of a flight instrument after both generators failed, backup battery power was exhausted early, due to the crew using an outdated checklist and not adhering to a checklist. 20 minutes after take-off, the crew of the aircraft contacted air traffic control reporting technical problems, controllers then diverted the aircraft to Simara Airport in Pipara Simara, Nepal, due to poor weather conditions at Kathmandu. Aviation officials said although the crew reported technical problems, they did not declare an emergency or request priority clearance to land. Five minutes after reporting issues with the aircraft, radar and radio contact with the aircraft was lost, the aircraft crashed in the town of Shikharpur, Narayani, around 50 miles south of Kathmandu. Witnesses reported there was no noise from the prior to the crash. The force of the crash spread wreckage in an area with a diameter of around 330 feet, all on board died in the crash, they included eight Nepalese citizens, as well as six foreigners. Of the foreigners, four were American women, one was a Briton, heavy rains in the area also led to the risk of flooding and landslides. Authorities announced a reward of Rs.50,000 for anyone who would find equipment that would help discover the cause of the crash. By 2 September, both the voice recorder and the flight data recorder of the crashed aircraft had been located. The government of Nepal formed a panel to help determine the cause of the crash. Despite initial reports that technical issues had resulted in the accident, flying in poor weather conditions, the flight crew would have had to rely only on their instruments, such a situation is known as instrument meteorological conditions. 2012 Agni Air Dornier 228 crash Yeti Airlines Flight 103 Accident report on Aviation Safety, archived from the original on 30 August 2010
Agni Air Flight 101
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The 9N-AHE, 4 months prior to the incident
30.
Air India Flight 855
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Air India Flight 855 was a scheduled passenger flight that crashed during the evening of New Years Day 1978 about 3 km off the coast of Bandra, Bombay. All 213 passengers and crew on board were killed, the crash is believed to have been caused by the captain having become spatially disoriented after the failure of one of the flight instruments in the cockpit. It was the deadliest aviation accident in India until the Charkhi Dadri mid-air collision in 1996, the aircraft involved was a Boeing 747-237B, registration VT-EBD, named Emperor Ashoka. It was the first 747 delivered to Air India, in April 1971, the departure was from Bombays Sahar Airport. The destination was Dubai International Airport in Dubai, approximately one minute after takeoff from runway 27, Captain M. L. Kukar made a right turn upon crossing the Bombay coastline over the Arabian Sea. Soon it began rolling to the left, and never regained level flight, just 101 seconds after leaving the runway the jet hit the Arabian Sea at an estimated 35-degree nose-down angle. There were no survivors among the 190 passengers and 23 crew members, the partially recovered wreckage revealed no evidence of explosion, fire, or any electrical or mechanical failure, and an initial theory of sabotage was ruled out. The investigation concluded that the cause was due to the irrational control inputs by the captain following complete unawareness of the attitude as his AI had malfunctioned. The crew failed to control based on the other flight instruments. US Federal District Judge James M. Spatial disorientation Sensory illusions in aviation John F. Kennedy, chapter Four, On A Bombay Night. Inside the Sky, A Meditation on Flight, design Induced Errors, which includes a discussion of the crash. Pre-crash photos of 747 VT-EBD at airliners. net
Air India Flight 855
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VT-EBD Emperor Ashoka two years before the accident
