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Pinger Locators
A towed pinger locator is a water-borne device used to locate the sonar "ping" from the underwater locator beacon which is fitted to the Cockpit Voice Recorders and Flight Data Recorders installed in commercial airliners. They can locate pingers at depths of up to underwater. Description The locator is mounted in a hydrodynamic shell, or "tow fish", connected by winch behind a surface vessel across the search area. The locator listens for the sound emanating from the beacon or "pinger". Once located, the beacon and its attached recorders can be retrieved by divers, submersibles or remotely operated vehicle (ROV), depending on depth. A model currently used by the United States Navy is the TPL-25, which has a weight of and a length of ; it is generally towed at . Most beacons transmit a pulse once a second at 37.5 kHz. The hydrophone must be positioned below the thermocline layer which reflects sounds, either back to the surface or back to the ocean floor. Since the pinge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Mile
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute ( of a degree) of latitude at the equator, so that Earth's polar circumference is very near to 21,600 nautical miles (that is 60 minutes × 360 degrees). Today the international nautical mile is defined as exactly . The derived unit of speed is the knot, one nautical mile per hour. Unit symbol There is no single internationally agreed symbol, with several symbols in use. * NM is used by the International Civil Aviation Organization. * nmi is used by the Institute of Electrical and Electronics Engineers and the United States Government Publishing Office. * M is used as the abbreviation for the nautical mile by the International Hydrographic Organization. * nm is a non-standard abbreviation used in many maritime applications and texts, including U.S. Government Coa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Towed Array Sonar
A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable that can be kilometers long, keeps the array's sensors away from the ship's own noise sources, greatly improving its signal-to-noise ratio, and hence the effectiveness of detecting and tracking faint contacts, such as quiet, low noise-emitting submarine threats, or seismic signals. A towed array offers superior resolution and range compared with hull-mounted sonar. It also covers the Baffles (submarine), baffles, the blind spot of hull-mounted sonar. However, effective use of the system limits a vessel's speed and care must be taken to protect the cable from damage. History During World War I, a towed sonar array known as the "Electric Eel" was developed by Harvey Hayes, a U.S. Navy physicist. This system is believed to be the first towed sonar array design. It employed two cables, each with a dozen hydrophones attached. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malaysia Airlines Flight 370
Malaysia Airlines Flight 370 (MH370/MAS370) was an international passenger flight operated by Malaysia Airlines that disappeared from radar on 8 March 2014, while flying from Kuala Lumpur International Airport in Malaysia to its planned destination, Beijing Capital International Airport in China. The cause of its disappearance has not been determined. It is widely regarded as the greatest mystery in aviation history, and remains the single deadliest case of aircraft disappearance. The crew of the Boeing 777-200ER, registered as 9M-MRO, last communicated with air traffic control (ATC) around 38 minutes after takeoff when the flight was over the South China Sea. The aircraft was lost from ATC's secondary surveillance radar screens minutes later but was tracked by the Malaysian military's primary radar system for another hour, deviating westward from its planned flight path, crossing the Malay Peninsula and Andaman Sea. It left radar range northwest of Penang Island ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Unrecovered Flight Recorders
This article provides a list of aircraft accidents and incidents for which flight data recorders (FDRs) and/or cockpit voice recorders (CVRs) were not recovered or were destroyed or otherwise failed to provide complete and correct information. FDRs and CVRs in commercial aircraft continuously record information and can provide key evidence in determining the causes of an aircraft loss. The greatest depth from which a flight recorder has been recovered is , for the CVR of South African Airways Flight 295. Most flight recorders are equipped with underwater locator beacons to assist searchers in recovering them from offshore crash sites; however, these beacons run off a battery and eventually stop transmitting. For various reasons, a flight recorder cannot always be recovered, and some recorders that are recovered are too damaged to provide any data. Some recorders have also failed to provide adequate information for various other reasons, such as poor maintenance, disconnection f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korean Air Lines Flight 007
Korean Air Lines Flight 007 (KE007/KAL007)In aviation, two types of Airline codes, airline designators are used. The flight number KAL 007, with the ICAO code for Korean Air Lines, was used by air traffic control. In ticketing, however, IATA codes are used instead, so the flight was referred to as KE007 in the booking systems and on the passengers' tickets. was a scheduled Korean Air Lines flight from New York City to Seoul via Anchorage, Alaska. On September 1, 1983, the flight was shot down by a Soviet Sukhoi Su-15, Sukhoi Su-15TM Flagon-F interceptor aircraft. The Boeing 747-230B airliner was en route from Anchorage to Seoul, but owing to a navigational mistake made by the crew, the airliner drifted from its planned route and flew through Soviet airspace. The Soviet Air Forces treated the unidentified aircraft as an intruding U.S. spy plane, and destroyed it with air-to-air missiles, after firing warning shots. The South Korean airliner eventually crashed into the sea near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air France Flight 447
Air France Flight 447 was a scheduled international passenger flight from Rio de Janeiro/Galeão International Airport, Rio de Janeiro, Brazil, to Charles de Gaulle Airport, Paris, France. On 1 June 2009, inconsistent airspeed indications and miscommunication led to the pilots inadvertently Stall (fluid dynamics), stalling the Airbus A330. They failed to recover the plane from the stall, and the plane crashed into the mid-Atlantic Ocean at 02:14 Coordinated Universal Time, UTC, killing all 228 passengers and crew on board. The Brazilian Navy recovered the first major wreckage and two bodies from the sea within five days of the accident, but the investigation by France's Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) was initially hampered because the aircraft's flight recorders were not recovered from the ocean floor until May 2011, nearly two years after the accident. The BEA's final report, released at a press conference on 5 July 2012, concluded that the aircr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emergency Position-indicating Radiobeacon Station
An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or Natural environment, environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening of the situation, although in some situations, mitigation may not be possible and agencies may only be able to offer palliative care for the aftermath. While some emergencies are self-evident (such as a natural disaster that threatens many lives), many smaller incidents require that an observer (or affected party) decide whether it qualifies as an emergency. The precise definition of an emergency, the agencies involved and the procedures used, vary by jurisdiction, and this is usually set by the government, whose agencies (emergency services) are responsible for emergency planning and management. Defining an emergency An incident, to be an emergency, conforms to one or more of the following, if it: * Poses an immediat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Recorder
A flight recorder is an electronic recording device placed in an aircraft for the purpose of facilitating the investigation of aviation accidents and incidents. The device may often be referred to colloquially as a "black box", an outdated name which has become a misnomer—they are now required to be painted Safety orange, bright orange, to aid in their recovery after accidents. There are two types of flight recording devices: the flight data recorder (FDR) preserves the recent history of the flight through the recording of dozens of parameters collected several times per second; the cockpit voice recorder (CVR) preserves the recent history of the sounds in the cockpit, including the conversation of the pilots. The two devices may be combined into a single unit. Together, the FDR and CVR objectively document the aircraft's flight history, which may assist in any later investigation. The two flight recorders are required by international regulation, overseen by the Internation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermocline
A thermocline (also known as the thermal layer or the metalimnion in lakes) is a distinct layer based on temperature within a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) with a high gradient of distinct temperature differences associated with depth. In the ocean, the thermocline divides the upper mixed layer from the calm deep water below. Depending largely on season, latitude, and turbulent mixing by wind, thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude, and local environmental conditions, such as tides and currents. Oceans Most of the heat energy of the sunlight that strikes the Earth is absorbed in the first few centimeters at the ocean's surface, which hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Locator Beacon
An underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation. Liquid water has been present on Earth for most of the history of the planet. The underwater environment is thought to be the place of the origin of life on Earth, and it remains the ecological region most critical to the support of life and the natural habitat of the majority of living organisms. Several branches of science are dedicated to the study of this environment or specific parts or aspects of it. A number of human activities are conducted in the more accessible parts of the underwater environment. These include research, underwater diving for work or recreation, and underwater warfare with submarines. It is hostile to humans in many ways and often inaccess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
