==== Falsehoods Programmers Believe About Aviation ====

some [[Falsehoods Programmers Believe]] via [[https://flightaware.engineering/falsehoods-programmers-believe-about-aviation/|flightaware.engineering]] by Ben Burwell 02 Jun 2025

====  Flights ====

  *  Flights depart from a gate
  *  Flights that depart from a gate [[https://www.flightaware.com/live/flight/AFR1/history/20250514/2040Z/KJFK/LFPG?ref=flightaware.engineering|only leave their gate once]]
  *  Flights depart within a few hours of the time they were scheduled to
  *  Flights depart [[https://www.flightaware.com/live/flight/PDT5965/history/20250508/2224Z/KCHO/KCLT?ref=flightaware.engineering|within a day]] of the time they were scheduled to
  *  Flights have schedules
  *  Flights take off and land [[https://www.flightaware.com/live/flight/N144NE/history/20250518/1747Z/KPSM/L%2042.98589%20-71.12891?ref=flightaware.engineering|at airports]]
  *  Airplanes (excluding helicopters) take off and land at airports
  *  Flights are at most [[https://www.flightaware.com/live/flight/SIA21/history/20250516/1345Z/KEWR/WSSS?ref=flightaware.engineering|a dozen or so hours long]]
  *  Okay, they're at most [[https://www.flightaware.com/live/flight/HBAL812/history/20190717/1738Z?ref=flightaware.engineering|a few days long]]
  *  Flights are identified by a flight number consisting of an airline's code plus some numbers, like UAL1234
  *  Flights [[https://www.flightaware.com/live/flight/C6031/history/20250521/1752Z/KBID/KFMH?ref=flightaware.engineering|are identified by either]] an airline flight number like UAL1234, or the aircraft's registration like N12345, B6459, or FHUVL
  *  A flight identifier like B6459 is unambiguously either a registration ([[https://www.flightaware.com/live/flight/B6459?ref=flightaware.engineering|B--6459]]), an airline flight number ([[https://www.flightaware.com/live/flight/JBU459?ref=flightaware.engineering|B6 459]]), or something else
  *  Flights don't have [[https://en.wikipedia.org/wiki/Change_of_gauge_(aviation)?ref=flightaware.engineering|multiple flight numbers]]
  *  Flights with multiple flight numbers unambiguously have one “main” flight number
  *  A particular trip's flight number(s) [[https://web.archive.org/web/20230328124705/https://community.southwest.com/t5/Blog/The-Science-behind-Flight-Numbers/ba-p/42760|never change]]
  *  The flight number shown on your ticket [[https://www.eurocontrol.int/service/call-sign-similarity-service?ref=flightaware.engineering|is what the pilots and air traffic control are using]]
  *  Flights don't use the code of some entirely unrelated airline in their flight identifier
  *  No flights use the same flight number within a day
  *  Surely at least no flights use the same flight number at the same time?
  *  Okay fine, separate flights from the same major passenger airline that depart within a few minutes of each other would not [[https://www.flightaware.com/live/flight/AAL2586/history/20250509/1935Z/TBPB/KCLT?ref=flightaware.engineering|both]] have the [[https://www.flightaware.com/live/flight/AAL2586/history/20250508/1935Z/TBPB/KCLT?ref=flightaware.engineering|same]] flight number... right?

====  Airports ====

  *  Airports [[https://en.wikipedia.org/wiki/Atat%C3%BCrk_Airport?ref=flightaware.engineering#Closure|never move]]
  *  Terminal and gate numbers have a consistent naming scheme
  *  Each runway is [[https://en.wikipedia.org/wiki/Hickam_Air_Force_Base?ref=flightaware.engineering|only used by one]] airport
  *  Airports always have two unique identifiers: a 4-letter Civil Aviation Organization (ICAO) code and a 3-letter International Air Transport Association (IATA) code
  *  Airports always have three unique identifiers: an ICAO, an IATA, and a regionally-administered location code
  *  The U.S. Department of Transportation [[https://www.bts.gov/topics/airlines-and-airports/world-airport-codes?ref=flightaware.engineering|assigns one]] canonical code to [[https://www.faa.gov/air_traffic/flight_info/aeronav/aero_data/loc_id_search/Encodes_Decodes/?ref=flightaware.engineering|each airport]] it oversees
  *  No airports have [[https://en.wikipedia.org/wiki/EuroAirport_Basel_Mulhouse_Freiburg?ref=flightaware.engineering|multiple IATA codes]]
  *  The ICAO code for airports in the U.S. [[https://www.flightaware.com/live/airport/PANC?ref=flightaware.engineering|always starts with the letter K]]
  *  For U.S. airports whose ICAO code starts with K, the [[https://en.wikipedia.org/wiki/McClellan%E2%80%93Palomar_Airport?ref=flightaware.engineering|last three letters]] are its IATA code
  *  You can tell which [[https://www.flightaware.com/live/airport/NZIR?ref=flightaware.engineering|geographic region]] an airport is in from its ICAO code
  *  Everything that has an IATA code [[https://en.wikipedia.org/wiki/List_of_IATA-indexed_railway_stations,_bus_stations_and_ferry_terminals?ref=flightaware.engineering|is an airport]]
  *  Everything that has an ICAO code [[https://en.wikipedia.org/wiki/Jezero_(crater)?ref=flightaware.engineering|is on Earth]]
  *  Airports have at least one well-known identifier of some sort

====  Airlines ====

  *  No [[https://en.wikipedia.org/wiki/SkyJet_Airlines?ref=flightaware.engineering|two]] airlines [[https://en.wikipedia.org/wiki/Euroavia_Airlines?ref=flightaware.engineering|share]] the same [[https://en.wikipedia.org/wiki/Airline_codes?ref=flightaware.engineering#IATA_airline_designator|IATA code]]
  *  No [[https://en.wikipedia.org/wiki/EasyJet_UK?ref=flightaware.engineering|airlines]] use [[https://en.wikipedia.org/wiki/EasyJet_Europe?ref=flightaware.engineering|multiple]] IATA or ICAO [[https://en.wikipedia.org/wiki/EasyJet_Switzerland?ref=flightaware.engineering|codes]]
  *  You can tell [[https://en.wikipedia.org/wiki/Aircraft_lease?ref=flightaware.engineering#Wet_lease|what airline is operating a flight]] by looking at the physical aircraft
  *  Airlines assign flight numbers to specific routes
  *  Airlines only assign flight numbers to [[https://en.wikipedia.org/wiki/Codeshare_agreement?ref=flightaware.engineering|flights they operate]]
  *  Airlines only assign flight numbers to [[https://www.flyertalk.com/forum/air-france-frequence-plus/1325488-how-fly-mlh-bsl.html?ref=flightaware.engineering|flights]]

====  Navigation ====

  *  Waypoint names are unique
  *  There is one [[https://en.wikipedia.org/wiki/Altitude?ref=flightaware.engineering#In_aviation|agreed-upon definition of altitude]]
  *  Flight information from Air Navigation Service Providers is accurate
  *  Okay, /pretty/ accurate; they wouldn't indicate that a flight had departed unless it really had
  *  If they indicate that a flight plan has been cancelled, then that flight definitely isn't going to operate --- it wouldn't simply be due to someone editing the flight plan
  *  At least their radar data accurately identifies each aircraft
  *  Radars with overlapping coverage areas agree on the location of a target they can both see
  *  If they send us a flight plan with the ICAO identifier of a known airport as the destination, then there must have been some intention of arriving there
  *  If an aircraft diverts to another destination, it won't [[https://www.flightaware.com/live/flight/AAL1372/history/20250516/1410Z/KMIA/KRIC?ref=flightaware.engineering|divert again]]

====  Transponders and ADS-B ====

  *  ADS-B messages only come from aircraft
  *  ADS-B messages only come from aircraft and airport service vehicles
  *  ADS-B messages only come from vehicles of some kind
  *  The GPS position in ADS-B messages [[https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation)?ref=flightaware.engineering|is accurate]]
  *  The GPS position in ADS-B messages is accurate [[https://en.wikipedia.org/wiki/Spoofing_attack?ref=flightaware.engineering#Global_navigation_satellite_system_spoofing|within some known uncertainty]] radius
  *  ADS-B messages always include the correct flight identification
  *  Transponders are correctly programmed to indicate the aircraft type (helicopter, airplane, balloon, etc)
  *  You can always determine a aircraft's registration number from its ADS-B messages
  *  Transponders are programmed with the correct Mode S address
  *  All of the transponders on a single aircraft are programmed with the same Mode S address
  *  Nobody will ever set their flight identification to weird things like NULL
  *  People will remember to update the transponder when the aircraft's registration changes
  *  ADS-B messages are always received exactly as they were transmitted
  *  No one ever transmits false ADS-B messages
  *  Transponders never break and rodents never chew through cables