Skywave Skip Radio Transmiissions.

https://en.wikipedia.org/wiki/Skywave

In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere.

Most long-distance shortwave (high frequency) radio communication—between 3 and 30 MHz—is a result of skywave propagation. Since the early 1920s amateur radio operators (or "hams"), limited to lower transmitter power thanbroadcast stations, have taken advantage of skywave for long distance (or "DX") communication.

skywave propagation is distinct from:

  • groundwave propagation, where radio waves travel near Earth's surface without being reflected or refracted by the atmosphere—the dominant propagation mode at lower frequencies,
  • line-of-sight propagation, in which radio waves travel in a straight line, the dominant mode at higher frequencies.

The ionosphere is a region of the upper atmosphere, from about 80 km to 1000 km in altitude, where neutral air is ionized by solar photons and cosmic rays. When high frequencysignals enter the ionosphere obliquely, they are back-scattered from the ionized layer as scatter waves.[1] If the midlayer ionization is strong enough compared to the signal frequency, a scatter wave can exit the bottom of the layer earthwards as if reflected from a mirror. Earth's surface (ground or water) then diffusely reflects the incoming wave back towards the ionosphere. Consequently, like a rock "skipping" across water, the signal may effectively "bounce" or "skip" between the earth and ionosphere two or more times (multihop propagation). Since at shallow incidence losses remain quite small, signals of only a few watts can sometimes be received many thousands of miles away as a result. This is what enables shortwave broadcasts to travel all over the world. 

also see Over the Horizon Radar (OTH)

Weather Ships

https://en.wikipedia.org/wiki/Weather_ship

A possible alternative for 


-Weather observation


-Ocean based communication relay stations or GPS 



-Plane tracking 

They assisted in Transatlantic flights 

http://www.gaflight.org/History%20of%20Aeradio.htm

n 1941, MAP took the operation off CPR to put the whole operation under the Atlantic Ferry Organization ("Atfero") was set up by Morris W. Wilson, a banker in Montreal. Wilson hired civilian pilots to fly the aircraft to the UK. The pilots were then ferried back in converted RAF Liberators. "Atfero hired the pilots, planned the routes, selected the airports [and] set up weather and radio communication stations. becmae  RAF Transport command in 1943 and Transport Command was renamed Air Support Command in 1967

Gander Aeradio

good source        http://www.gaflight.org/History%20of%20Aeradio.htm

Gander was selected as a suitible land plane base and radio operation moved there from Botwood in 1938.

radio telephony was not used till 1948, previously International morese code was used.

in 1941 ATFERO tool over , Originally the Americans had wanted to use these bases, no more than 400 to 500 miles apart, to fly shorter range single-engine fighters to Britain. These plans never reached fruition. However, the basic infrastructure survived the war and left Canada with a network of extremely useful communications and transportation facilities in the north 

It was around this time that Aeradio became known as the “Signals Centre” or “Signals” for short. 

Royal Air Force Ferry Command, which later changed its name to the RAF Transport Command, assumed control of the operation. 


After the war, the Civil Aviation Division of the Newfoundland Government assumed control of radio operations until it was passed to the Canadian Air Transportation Administration.  This department, which holds control to the present day, assumed responsibility for all communications relevant to the operation of transatlantic crossing and controls whilst en route.


With the introduction of radio telephone in 1948 and with the increase in the AOR (area of responsibility) for Gander in 1950 when oceanic control moved from Moncton to Gander, Aeradio entered a new era in Canada Aviation history.  Operations continued to improve as an expanded number of frequencies were introduced when the present building was built and commissioned in 1957.



Major decisions were taken at international civil aviation conferences in 1944 and 1945. There the Allied Powers adopted a system of air traffic control for the world that was based on the one that had been developed by Canada and the United States and agreed to by Britain, largely to handle transatlantic flying. Ferry Command had been instrumental in this process. Delegates to these conferences decided to make Montreal the headquarters of the new Provisional International Civil Aviation Organization or PICAO, at least partly because of the important role the city had played in the world-wide activities of Ferry Command. ICAO ( 1 ,



The 1960s saw further improvements and developments in technology of electronic equipment such as, transmitters, receivers, teletypewriters and landline connections but apparently technology could not keep abreast of increased demands by multi-international air carriers requesting the services of Gander Aeradio during their regular flights across the North Atlantic.  This led to the last major developments of the 1970s when the reporting system became fully computerized, thereby, increasing the speed which in-flight communications could be processed.  The change from AM (amplitude modulation) to SSB (single sideband) transmission also took place during this period.


This year, 1986, will mark a new milestone when Gander International Flight Service completes its planned move and enters the latest state-of-the-art technology of the eighties.


Today, Gander International Flight Service Station is the largest aeradio station operated by the Ministry of Transport in Canada, both in terms of volume of messages and the number of staff.  Fifty-four specialists operate on a continuous 24 hour rotating shift under a mandate from ICAO (International Civil Aviation Organization) to provide for the safe and expedient movement of aircraft with the 1,152,000 square miles of Gander’s oceanic area.  In maintaining a liaison between aircraft and ATC, last year Gander IFSS provided communications to approximately 115,000 aircraft, resulting in about a half million contacts.  These contacts included everything from enroute safety messages, company reclearance messages, significant enroute weather information and dangers to navigation, not to mention distress communications and communications of an urgent nature.  In addition to the nine air/ground circuits, the station also operates a weather broadcast position, known as Volmet, sending out two ten minute weather broadcasts every hour. 





To aid aircraft crossing the Atlantic, six nations grouped to divide the Atlantic into ten zones. Each zone had a letter and a vessels station in that zone, providing radio relay, radio navigation beacons, weather reports and rescues if an aircraft went down. The six nations of the group split the cost of these vessels.[45]






A weather ship was a ship stationed in the ocean as a platform for surface and upper air meteorological observations for use inweather forecasting. They were primarily located in the north Atlantic and north Pacific oceans, reporting via radio. In addition to their weather reporting function, these vessels aided in search and rescue operations, supported transatlantic flights,[1][2] acted as research platforms for oceanographers, monitored marine pollution, and aided weather forecasting both by weather forecasters and within computerized atmospheric models. Research vessels remain heavily used in oceanography, including physical oceanography and the integration of meteorological and climatological data in Earth system science.

The idea of a stationary weather ship was proposed as early as 1921 by Météo-France to help support shipping and the coming of transatlantic aviation. They were used during World War II but had no means of defense, which led to the loss of several ships and many lives. On the whole, the establishment of weather ships proved to be so useful during World War II for Europe and North America that the International Civil Aviation Organization (ICAO) established a global network of weather ships in 1948, with 13 to be supplied by Canada, the United States, and Europe. This number was eventually negotiated down to nine. The agreement of the use of weather ships by the international community ended in 1985.

Weather ship observations proved to be helpful in wind and wave studies, as commercial shipping tended to avoid weather systems for safety reasons, whereas the weather ships did not. They were also helpful in monitoring storms at sea, such as tropical cyclones. Beginning in the 1970s, their role was largely superseded by weather buoys because of the ships' significant cost. The removal of a weather ship became a negative factor in forecasts leading up to the Great Storm of 1987. The last weather ship was Polarfront, known as weather station M ("Mike"), which was removed from operation on January 1, 2010. Weather observations from ships continue from a fleet of voluntary merchant vessels in routine commercial operation.


Transatlantic routes[edit]

See also: Atlantic Bridge (flight route)

Unlike over land, transatlantic flights use standardized aircraft routes called North Atlantic Tracks (NATs). These change daily in position (although altitudes are standardized) to compensate for weather—particularly the jet stream tailwinds and headwinds, which may be substantial at cruising altitudes and have a strong influence on trip duration and fuel economy. Eastbound flights generally operate during night-time hours, while westbound flights generally operate during daytime hours, for passenger convenience. The eastbound flow, as it is called, generally makes European landfall from about 0600UT to 0900UT. The westbound flow generally operates within a 1200–1500UT time-slot. Restrictions on how far a given aircraft may be from an airport also play a part in determining its route; in the past, airliners with three or more engines were not restricted, but a twin-engine airliner was required to stay within a certain distance of airports that could accommodate it (since a single engine failure in a four-engine aircraft is less crippling than a single engine failure in a twin). Modern aircraft with two engines flying transatlantic (the most common models used for transatlantic service being the Airbus A330, Boeing 767 and Boeing 777) have to beETOPS certified.


Gaps In Air Traffic Control And Radar Coverage Over Large Stretches Of The Earth's Oceans, As Well As An Absence Of Most Types Of Radio Navigation Aids, Impose A Requirement For A High Level Of Autonomy In Navigation Upon Transatlantic Flights. Aircraft Must Include Reliable Systems That Can Determine The Aircraft's Course And Position With Great Accuracy Over Long Distances. In Addition To The Traditional Compass, Inertials And Satellite Navigation Systems Such As GPS All Have Their Place In Transatlantic Navigation. Land-Based Systems Such As VOR And DME, Because They Operate "Line Of Sight", Are Mostly Useless For Ocean Crossings, Except In Initial And Final Legs Within About 240 Nautical Miles (440 Km) Of Those Facilities. In The Late 1950s And Early 1960s An Important Facility For Low-Flying Aircraft Was The Radio Range. Inertial Navigation Systems Became Prominent In The 1970s.

VOLMET

https://en.wikipedia.org/wiki/VOLMET

VOLMET (French origin VOL (flight) and METEO (weather)), or meteorological information for aircraft in flight, is a worldwide networkof radio stations that broadcast TAF, SIGMET and METAR reports on shortwave frequencies, and in some countries on VHF too. Reports are sent in upper sideband mode, using automated voice transmissions.

Pilots on international routes, such as North Atlantic Tracks, use these transmissions to avoid storms and turbulence, and to determine which procedures to use for descent, approach, and landing.

The VOLMET network divides the world into specific regions, and individual VOLMET stations in each region broadcast weather reports for specific groups of air terminals in their region at specific times, coordinating their transmission schedules so as not to interfere with one another. Schedules are determined in intervals of five minutes, with one VOLMET station in each region broadcasting reports for a fixed list of cities in each interval. These schedules repeat every hour.

 ACARS (/ˈeɪkɑːrz/; an acronym for Aircraft Communications Addressing and Reporting System)

https://en.wikipedia.org/wiki/Aircraft_Communications_Addressing_and_Reporting_System

is a digital datalink system for transmission of short messages between aircraft and ground stations via airband radio or satellite. The protocol was designed by ARINC and deployed in 1978,[1] using the Telex format. More ACARS radio stations were added subsequently by SITA.


ACARS as a term refers to the complete air and ground system, consisting of equipment on board, equipment on the ground, and a service provider.


On-board ACARS equipment[3] consists of end systems with a router, which routes messages through the air-ground subnetwork.


Ground equipment is made up of a network of radio transceivers managed by a central site computer called AFEPS (Arinc Front End Processor System), which handles and routes messages. Generally, ground ACARS units are either government agencies such as the Federal Aviation Administration, an airline operations headquarters, or, for small airlines or general aviation, a third-party subscription service. Usually government agencies are responsible for clearances, while airline operations handle gate assignments, maintenance, and passenger needs.


The ACARS equipment on the aircraft is linked to that on the ground by the datalink service provider. Because the ACARS network is modeled after the point-to-point telex network, all messages come to a central processing location to be routed. ARINC and SITA are the two primary service providers, with smaller operations from others in some areas. Some areas have multiple service providers.




ACARS messages may be sent using a choice of communication methods, such as VHF or HF, either direct to ground or via satellite, using minimum-shift keying (MSK)modulation.[8]


ACARS can send messages over VHF if a VHF ground station network exists in the current area of the aircraft. VHF communication is line-of-sight propagation and the typical range is up to 200 nautical miles at high altitudes. Where VHF is absent, an HF network or satellite communication may be used if available. Satellite coverage may be limited at high latitudes (trans-polar flights).


n the wake of the crash of Air France Flight 447 in 2009, there was discussion about making ACARS an "online-black-box"[10] to reduce the effects of the loss of a flight recorder. However no changes were made to the ACARS system.

In March 2014, ACARS messages and Doppler analysis of ACARS satellite communication data played a very significant role in efforts to trace Malaysia Airlines Flight 370 to an approximate location. While the primary ACARS system on board MH370 had been switched off, a second ACARS system called Classic Aero was active as long as the plane was powered up, and kept trying to establish a connection to an Inmarsat satellite every hour.[11]


In 2002, ACARS was added to the NOAA Observing System Architecture. Thus commercial aircraft can act as weather data providers for weather agencies to use in their forecast models, sending meteorological observations like winds and temperatures over the ACARS network. NOSA provides real-time weather maps.



See also[edit]






A flight management system (FMS) is a fundamental component of a modern airliner's avionics. An FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew to the point that modern civilian aircraft no longer carry flight engineers or navigators. A primary function is in-flight management of the flight plan. Using various sensors (such as GPS and INS often backed up by radio navigation) to determine the aircraft's position, the FMS can guide the aircraft along the flight plan. From the cockpit, the FMS is normally controlled through a Control Display Unit (CDU) which incorporates a small screen and keyboard or touchscreen. The FMS sends the flight plan for display to the Electronic Flight Instrument System (EFIS), Navigation Display (ND), or Multifunction Display (MFD).

The modern FMS was introduced on the Boeing 767, though earlier navigation computers did exist.[1] Now, systems similar to FMS exist on aircraft as small as the Cessna 182. In its evolution an FMS has had many different sizes, capabilities and controls. However certain characteristics are common to all FMS.

All FMS contain a navigation database. The navigation database contains the elements from which the flight plan is constructed. These are defined via the ARINC 424 standard. The navigation database (NDB) is normally updated every 28 days, in order to ensure that its contents are current. Each FMS contains only a subset of the ARINC data, relevant to the capabilities of the FMS.

The NDB contains all of the information required for building a flight plan, consisting of:

Waypoints can also be defined by the pilot(s) along the route or by reference to other waypoints with entry of a place in the form of a waypoint (e.g. a VOR, NDB, ILS, airport or waypoint/intersection)

The flight plan is generally determined on the ground, before departure It is entered into the FMS either by typing it in, selecting it from a saved library of common routes (Company Routes) or via an ACARS datalink with the airline dispatch center.

During preflight, other information relevant to managing the flight plan is entered. This can include performance information such as gross weight, fuel weight and center of gravity. It will include altitudes including the initial cruise altitude. For aircraft that do not have a GPS, the initial position is also required.

Once in flight, a principal task of the FMS is to determine the aircraft's position and the accuracy of that position. Simple FMS use a single sensor, generally GPS in order to determine position. But modern FMS use as many sensors as they can, such as VORs, in order to determine and validate their exact position. Some FMS use a Kalman filter to integrate the positions from the various sensors into a single position. Common sensors include:

  • Airline quality GPS receivers act as the primary sensor as they have the highest accuracy and integrity.
  • Radio aids designed for aircraft navigation act as the second highest quality sensors.
  • These include;
    • Scanning DME (distance measuring equipment) that check the distances from five different DME stations simultaneously in order to determine one position every 10 seconds or so.[2]
    • VORs (VHF omnidirectional radio range) that supply a bearing. With two VOR stations the aircraft position can be determined, but the accuracy is limited.
  • Inertial reference systems (IRS) use ring laser gyros and accelerometers in order to calculate the aircraft position. Theyare highly accurate and independent of outside sources. Airliners use the weighted average of three independent IRS to determine the “triple mixed IRS” position.

The FMS constantly crosschecks the various sensors and determines a single aircraft position and accuracy. The accuracy is described as the Actual Navigation Performance (ANP) a circle that the aircraft can be anywhere within measured as the diameter in nautical miles. Modern airspace has a set required navigation performance (RNP). The aircraft must have its ANP less than its RNP in order to operate in certain high-level airspace.

Given the flight plan and the aircraft's position, the FMS calculates the course to follow. The pilot can follow this course manually (much like following a VOR radial), or the autopilot can be set to follow the course.

The FMS mode is normally called LNAV or Lateral Navigation for the lateral flight plan and VNAV or vertical navigation for the vertical flight plan. VNAV provides speed and pitch or altitude targets and LNAV provides roll steering command to the autopilot.

Sophisticated aircraft, generally airliners such as the Airbus A320 or Boeing 737 and larger, have full performance Vertical Navigation (VNAV).

The first aircraft to feature this use were Boeing 757 and 767 airliners in 1982. (so 1982 is considered sophisticated?) 

The purpose of VNAV is to predict and optimize the vertical path. Guidance includes control of the pitch axis and control of the throttle.

When used on approach to landing, VNAV follows a calculated approach path from a Final Approach Fix or Waypoint to the runway, ie waypoints within the FMS navigation database. The path can either be based on stored database altitudes as displayed on the altimetry system ("Baro VNAV"), or as corrected within more advanced FMS equipment.

During final landing approach, altitude must be controlled more accurately than heights referenced to Mean Sea Level (MSL) as barometric altimetry provides. An ILS Glide Slope signal originating from the landing point provides needed vertical alignment down to the final 100 ft. Commercial pilots rely on visual cues, and a down-looking radar altimeter annunciator that calls out Above Ground Level (AGL) height 

Future systems will derive altitudes from GPS, however, raw GPS elevations are referenced to worldwide average sea-level. Local sea-levels depart from this average by up to +- 200 meters, obviously too much error to use for auto-takeoff/landing.

But this Boeing VNAV document from 2006states "Original intent of the features was for enroute navigation. No early vision into future operations such as RNP / RNAV (terminal area) / GPS / 4 D paths"

The GEOID99 software tables correct raw GPS elevation so that it is referenced to local sea-level for any location. A down-looking, terrain-reflecting sensor will take over below 100' as the primary AGL indicator.

Completely automating the final descent/touchdown under all flying conditions is unlikely, and thus pilot-in-the-loop will remain the primary means of vertical navigation low to the ground.

This feature is implemented in some new ATR.[1]

https://en.wikipedia.org/wiki/Flight_management_system



ARINC

ARINC HELPS VIRGIN ATLANTIC AIRWAYS’ PASSENGERS JOIN THE TEXT MESSAGING REVOLUTION - see pdf

http://web.archive.org/web/20060211160041/http://www.arinc.com/news/newsletters/gl_10_02.pdf

Military comms

very little mention of satellites

https://en.wikipedia.org/wiki/Military_communications


but mention

https://en.wikipedia.org/wiki/Tropospheric_scatter

Tropospheric scatter (also known as troposcatter) is a method of communicating with microwave radio signals over considerable distances – often up to 300 km, and further depending on terrain and climate factors. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at particular frequencies are randomly scattered as they pass through the upper layers of thetroposphere. Radio signals are transmitted in a tight beam aimed just above the horizon in the direction of the receiver station. As the signals pass through the troposphere, some of the energy is scattered back toward the Earth, allowing the receiver station to pick up the signal.[1]


Terestial microwave

http://www.advantechwireless.com/product-category/terrestrial-microwave-communications/

http://www.searchlake.com/difference-between-terrestrial-satellite-microwave/

Navigation[edit]

Main article: Radio navigation


Radio direction-finding is the oldest form of radio navigation. Before 1960 navigators used movable loop antennas to locate commercial AM stations near cities. In some cases they used marine radiolocation beacons, which share a range of frequencies just above AM radio with amateur radio operators. LORAN systems also used time-of-flight radio signals, but from radio stations on the ground.

Very High Frequency Omnidirectional Range (VOR), systems (used by aircraft), have an antenna array that transmits two signals simultaneously. A directional signal rotates like a lighthouse at a fixed rate. When the directional signal is facing north, an omnidirectional signal pulses. By measuring the difference in phase of these two signals, an aircraft can determine its bearing or radial from the station, thus establishing a line of position. An aircraft can get readings from two VORs and locate its position at the intersection of the two radials, known as a "fix."

When the VOR station is collocated with DME (Distance Measuring Equipment), the aircraft can determine its bearing and range from the station, thus providing a fix from only one ground station. Such stations are called VOR/DMEs. The military operates a similar system of navaids, called TACANs, which are often built into VOR stations. Such stations are called VORTACs. Because TACANs include distance measuring equipment, VOR/DME and VORTAC stations are identical in navigation potential to civil aircraft.

 Inertial navigation system (INS)

https://en.wikipedia.org/wiki/Inertial_navigation_system

is a navigation aid that uses a computer, motion sensors (accelerometers) and rotation sensors (gyroscopes) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references.[1] It is used on vehicles such as ships, aircraft,submarines, guided missiles, and spacecraft. Other terms used to refer to inertial navigation systems or closely related devices include inertial guidance system, inertial instrument, inertial measurement units (IMU) and many other variations. Older INS systems generally used an inertial platform as their mounting point to the vehicle, and the terms are sometimes considered synonymous.

A wide range of applications including the navigation of aircraft, tactical and strategic missiles, spacecraft, submarines and ships. Recent advances in the construction of microelectromechanical systems (MEMS) have made it possible to manufacture small and light inertial navigation systems. These advances have widened the range of possible applications to include areas such as human and animal motion capture.

An inertial navigation system includes at least a computer and a platform or module containing accelerometers, gyroscopes, or other motion-sensing devices. The INS is initially provided with its position and velocity from another source (a human operator, a GPS satellite receiver, etc.), and thereafter computes its own updated position and velocity by integrating information received from the motion sensors. The advantage of an INS is that it requires no external references in order to determine its position, orientation, or velocity once it has been initialized.

Accelerometers measure the linear acceleration of the system in the inertial reference frame,Based on this information alone, they know how the vehicle is accelerating relative to itself, that is, whether it is accelerating forward, backward, left, right, up (toward the car's ceiling), or down (toward the car's floor) measured relative to the car, but not the direction relative to the Earth, since they did not know what direction the car was facing relative to the Earth when they felt the accelerations.

Inertial navigation systems were originally developed for rockets in the 1950s. American rocket pioneer Robert Goddard experimented with rudimentary gyroscopic systems. Dr. Goddard's systems were of great interest to contemporary German pioneers including Wernher von Braun. The systems entered more widespread use with the advent of spacecraft, guided missiles, and commercial airliners.

IMUs (Inertial Measurement Units) were used  for Apollo Guidance and Navigation systems for the Command Module and the Lunar Module 

One example of a popular INS for commercial aircraft was the Delco Carousel, which provided partial automation of navigation in the days before complete flight management systems became commonplace.

Inertial guidance systems are now usually combined with satellite navigation systems through a digital filtering system. The inertial system provides short term data, while the satellite system corrects accumulated errors of the inertial system.

An inertial guidance system that will operate near the surface of the earth must incorporate Schuler tuning so that its platform will continue pointing towards the center of the earth as a vehicle moves from place to place.

TIMU (Timing & Inertial Measurement Unit) sensors[edit]

DARPA's Microsystems Technology Office( MTO) department is working on a Micro-PNT ("Micro-Technology for Positioning, Navigation and Timing") program to design "TIMU" ("Timing & Inertial Measurement Unit") chips that does absolute position tracking on a single chip without GPS aided navigation.[12][13][14]

Micro-PNT adds a highly accurate master timing clock[15] integrated into an IMU (Inertial Measurement Unit) chip, making it a "TIMU" ("Timing & Inertial Measurement Unit") chip. So these TIMU chips for Micro-PNT have integrated 3-axis gyroscope, 3-axis accelerometer, and 3-axis magnetometer, and together with the integrated highly accurate master timing clock it simultaneous measure the motion tracked and combines that with timing from the synchronized clock, and with sensor fusion it makes a single chip that does absolute position tracking, all without external transmitters/transceivers.[12][13]

GPS


Korean Air Lines Flight 007 (also known as KAL007 and KE007)[note 2] was a scheduled Korean Air Lines flight from New York City to Seoul via Anchorage. On September 1, 1983, the airliner serving the flight was shot down by a Soviet Su-15 interceptor, near Moneron Island west of Sakhalin in the Sea of Japan. The interceptor's pilot was Major Gennadi Osipovich. All 269 passengers and crew aboard were killed, including Larry McDonald, a Representative from Georgia in the United States House of Representatives. The aircraft was en route from Anchorage, Alaska, to Seoul when it flew through Soviet prohibited airspace around the time of a U.S. aerial reconnaissance mission.

The autopilot system used at the time had four basic control modes: HEADING, VOR/LOC, ILS, and INS. 

HEADING mode maintains constant magnetic course selected by the pilot.

VOR/LOC mode maintained the plane on a specific course, transmitted from a VOR (VHF omnidirectional range, a type of short-range radio signal transmitted from ground beacons) or Localizer (LOC) beacon selected by the pilot.

ILS (instrument landing system) mode tracks both vertical and lateral course beacons, which led to a specific runway selected by the pilot.

INS (inertial navigation system) mode maintains the plane on lateral course lines between selected flight plan waypoints programmed into the INS computer.

At about 10 minutes after take-off, KAL 007, flying on a heading of 245 degrees, began to deviate to the right (north) of its assigned route to Bethel, and continued to fly on this constant heading for the next five and a half hours.[21] 

Some time after leaving American territorial waters, KAL Flight 007 crossed the International Date Line, where the local date shifted from August 31, 1983 to September 1, 1983.

KAL 007 continued its journey, ever increasing its deviation—60 nautical miles (110 km) off course at waypoint NABIE, 100 nautical miles (190 km) off course at waypoint NUKKS, and 160 nautical miles (300 km) off course at waypoint NEEVA—until it reached the Kamchatka Peninsula.[9]

At 15:51 UTC, according to Soviet sources,[23] KAL 007 entered the restricted airspace of the Kamchatka Peninsula. The buffer zone extended 200 kilometers (120 mi) from Kamchatka's coast and is known as a flight information region (FIR). The 100-kilometre (62 mi) radius of the buffer zone nearest to Soviet territory had the additional designation of prohibited airspace. When KAL 007 was about 130 kilometres (81 mi) from the Kamchatka coast, four MiG-23 fighters were scrambled to intercept the Boeing 747.[8]

International Civil Aviation Organization (ICAO) simulation and analysis of the flight data recorder determined that this deviation was probably caused by the aircraft's autopilot system operating in HEADING mode, after the point that it should have been switched to the INS mode.[8][22] 

According to the ICAO, the autopilot was not operating in the INS mode either because the crew did not switch the autopilot to the INS mode (shortly after Cairn Mountain), or they did select the INS mode, but the computer did not transition from INERTIAL NAVIGATION ARMED to INS mode because the aircraft had already deviated off track by more than the 7.5 nautical miles (13.9 km) tolerance permitted by the inertial navigation computer. Whatever the reason, the autopilot remained in the HEADING mode, and the problem was not detected by the crew.[8]

The Soviet Union initially denied knowledge of the incident,[2] but later admitted shooting it down, claiming that the aircraft was on a MASINT spy mission.[3] The Politburo of the Communist Party of the Soviet Union said it was a deliberate provocation by the United States[4] to test the Soviet Union's military preparedness, or even to provoke a war. The  White House accused the Soviet Union of obstructing search and rescue operations.[5] The Soviet Armed Forces suppressed evidence sought by the International Civil Aviation Organization (ICAO) investigation, such as the flight data recorders,[6] which were not released until eight years later after the dissolution of the Soviet Union.[7]

As a result of the incident the United States altered tracking procedures for aircraft departing from Alaska. The interface of the autopilot used on airliners was redesigned to make it more ergonomic.[8] In addition, the event was one of the most important single events that prompted the Reagan administration to allow worldwide access to the United States military satellite navigation system DNSS, which was classified at the time.

Today this system, and others like it, are known as GPS.


Flight 007 has been the subject of ongoing controversy and has spawned a number of conspiracy theories.[125] Many of these are based on the suppression of evidence such as the flight data recorders,[114] unexplained details such as the role of a USAF RC-135 surveillance aircraft,[31][126] the untimely destruction of the U.S. Air Force's King Salmon radar data, or merely Cold War disinformation and propaganda.[127][128][129]


No body parts were recovered  by the Soviet search team but they did hand over to the Americans and Japanese, among other things, single and paired footwear. With footwear that the Japanese also retrieved, the total came to 213 men's, women's and children's dress shoes, sandals, and sports shoes.[71] The Soviets said that these were all that they had retrieved; they had found floating in the water or washed up on the shores of Sakhalin and Moneron islands.

Family members of KAL 007 passengers later stated that these shoes were worn by their loved ones for the flight. 

Nothing was found by the joint U.S.–Japanese–South Korean search and rescue/salvage operations.

Eight days after the shootdown, human remains appeared on the north shore of Hokkaido, Japan. These human remains, including body parts, tissues, and two partial torsos, totaled 13. All were unidentifiable, but one partial torso was that of a Caucasian woman as indicated by auburn hair on a partial skull, and one partial body was of an Asian child (with glass embedded). There was no luggage recovered. Of the non-human remains that the Japanese recovered were various items including dentures, newspapers, seats, books, eight KAL paper cups, shoes, sandals, and sneakers, a camera case, a "please fasten seat belt" sign, an oxygen mask, a handbag, a bottle of dish washing fluid, several blouses, an identity card belonging to 25-year-old passenger Mary Jane Hendrie[76] of Sault Ste. Marie, Ontario, Canada, and the business card of passenger Kathy Brown-Spier.[77] These items generally come from the passenger cabin of an aircraft. None of the items found generally come from the cargo hold of a plane, such as suitcases, packing boxes, industrial machinery, instruments, and sports equipment.

In 1991, Russian newspaper Izvestia published a series of interviews with Soviet military personnel who had been involved in salvage operations to find and recover parts of the aircraft.[35]. Since no human remains or luggage were found on the surface in the impact area, the divers expected to find the remains of passengers who had been trapped in the submerged wreckage of the aircraft on the seabed.. ICAO also interviewed a number of these divers for its 1993 report: "In addition to the scraps of metal, they observed personal items, such as clothing, documents and wallets. Although some evidence of human remains was noticed by the divers, they found no bodies."[81]

Divers comments below

Tinro ll submersible Captain Mikhail Igorevich Girs' diary: Submergence 10 October. Aircraft pieces, wing spars, pieces of aircraft skin, wiring, and clothing. But—no people. The impression is that all of this has been dragged here by a trawl rather than falling down from the sky...’[80]

Vyacheslav Popov: "I will confess that we felt great relief when we found out that there were no bodies at the bottom. Not only no bodies; there were also no suitcases or large bags. I did not miss a single dive. I have quite a clear impression: The aircraft was filled with garbage, but there were really no people there. Why? Usually when an aircraft crashes, even a small one... As a rule there are suitcases and bags, or at least the handles of the suitcases."

A number of civilian divers, whose first dive was on September 15, two weeks after the shootdown, state that Soviet military divers and trawls had been at work before them:

Diver Viyacheslav Popov: "As we learned then, before us the trawlers had done some ‘work’ in the designated quadrant. It is hard to understand what sense the military saw in the trawling operation. First drag everything haphazardly around the bottom by the trawls, and then send in the submersibles?...It is clear that things should have been done in the reverse order.”

On September 7, Japan and the United States jointly released a transcript of Soviet communications, intercepted by the listening post at Wakkanai, to an emergency session of the United Nations Security Council.[89] Reagan issued a National Security Directive stating that the Soviets were not to be let off the hook, and initiating "a major diplomatic effort to keep international and domestic attention focused on the Soviet action".[28] 

The National Transportation Safety Board (NTSB) was legally required to investigate. On the morning of September 1, the NTSB chief in Alaska, James Michelangelo, received an order from the NTSB in Washington at the behest of the State Department requiring all documents relating to the NTSB investigation to be sent to Washington, and notifying him that the State Department would now conduct the investigation.[94]

The U.S. State Department, after closing the NTSB investigation on the grounds that it was not an accident, pursued an International Civil Aviation Organization (ICAO)  investigation instead. this action was illegal, and that in deferring the investigation to the ICAO, the Reagan administration effectively precluded any politically or militarily sensitive information from being subpoenaed that might have embarrassed the administration or contradicted its version of events.[95] Unlike the NTSB, ICAO can subpoena neither persons nor documents and is dependent on the governments involved—in this incident, the United States, the Soviet Union, Japan, and South Korea—to supply evidence voluntarily.

ICAO did not have the authority to compel the states involved to hand over evidence, instead having to rely on what they voluntarily submitted.[97]  Consequently, the investigation did not have access to sensitive evidence such as radar data, intercepts, ATC tapes, or the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) (whose discovery the U.S.S.R. had kept secret). A number of simulations were conducted with the assistance of Boeing and Litton (the manufacturer of the navigation system).[98]

 ICAO released their report December 2, 1983, which concluded that the violation of Soviet airspace was accidental: One of two explanations for the aircraft's deviation was that the autopilot had remained in HEADING hold instead of INS mode after departing Anchorage. They postulated that this inflight navigational error was caused by either the crew's failure to select INS mode, or the inertial navigation's not activating when selected, because the aircraft was already too far off track.[8] 

The report included a statement by the Soviet Government claiming "no remains of the victims, the instruments or their components or the flight recorders have so far been discovered.

It is customary for the Air Force to impound radar trackings involving possible litigation in cases of aviation accidents.[106] In the civil litigation for damages, the United States Department of Justice explained that the tapes from the Air Force radar installation at King Salmon, Alaska pertinent to KAL 007's flight in the Bethel area had been destroyed and could therefore not be supplied to the plaintiffs. At first Justice Department lawyer Jan Van Flatern stated that they were destroyed 15 days after the shootdown. Later, he said he had "misspoken" and changed the time of destruction to 30 hours after the event. A Pentagon spokesman concurred, saying that the tapes are re-cycled for reuse from 24–30 hours afterwards;[107] the fate of KAL 007 was known inside this time frame.[106]


Eventually in November 1992, President Yeltsin handed the two recorder containers to Korean President Roh Tae-Woo, but not the tapes themselves. The following month, the ICAO voted to reopen the KAL 007 investigation in order to take the newly released information into account. The tapes were handed to ICAO in Paris on January 8, 1993.[7] Also handed over at the same time were tapes of the ground to air communications of the Soviet military.[113]The tapes were transcribed by the Bureau d'Enquêtes et d'Analyses pour la sécurité de l'Aviation Civile (BEA) in Paris in the presence of representatives from Japan, The Russian Federation, South Korea, and the United States.[113]

A 1993 official enquiry by the Russian Federation absolved the Soviet hierarchy of blame, determining that the incident was a case of mistaken identity.[84] On May 28, 1993, the ICAO presented its second report to the Secretary-General of the United Nations.

"The Report of the Completion of the Fact Finding Investigation",[121] and is appended to it. These transcripts (of two reels of tape, each containing multiple tracks) are time specified, some to the second, of the communications between the various command posts and other military facilities on Sakhalin from the time of the initial orders for the shootdown and then through the stalking of KAL 007 by Maj. Osipovich in his Sukhoi 15 interceptor, the attack as seen and commented on by General Kornukov, Commander of Sokol Air Base, down the ranks to the Combat Controller Captain Titovnin.[122]

The transcripts include the post-attack flight of KAL 007 until it had reached Moneron Island, the descent of KAL 007 over Moneron, the initial Soviet SAR missions to Moneron, the futile search of the support interceptors for KAL 007 on the water, and ending with the debriefing of Osipovich on return to base. Some of the communications are the telephone conversations between superior officers and subordinates and involve commands to them, while other communications involve the recorded responses to what was then being viewed on radar tracking KAL 007. These multi-track communications from various command posts telecommunicating at the same minute and seconds as other command posts were communicating provide a "composite" picture of what was taking place.[122]

The data from the CVR and the FDR revealed that the recordings broke off after the first minute and 44 seconds of KAL 007's post missile detonation 12 minute flight. The remaining minutes of flight would be supplied by the Russia 1992 submission to ICAO of the real-time Soviet military communication of the shootdown and aftermath. The fact that both recorder tapes stopped exactly at the same time 1 minute and 44 seconds after missile detonation (18:38:02 UTC) without the tape portions for the more than 10 minutes of KAL 007's post detonation flight before it descended below radar tracking (18:38 UTC) finds no explanation in the ICAO analysis, "It could not be established why both flight recorders simultaneously ceased to operate 104 seconds after the attack. The power supply cables were fed to the rear of the aircraft in raceways on opposite sides of the fuselage until they came together behind the two recorders."[43]