# Airline flight path **URL:** \ **Category:** Factual Questions\ **Created:** [October 22, 2008, 1:50am UTC](https://boards.straightdope.com/t/airline-flight-path/468998 "2008-10-22T01:50:33Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 22, 2008, 1:50am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/1 "2008-10-22T01:50:33Z")
Mrs. Plant flew to Long Island today. Watching on a website, I noticed that Southwest flew from Baltimore West out to sea, north east and then north to Long Island. Why didn’t they fly in a straight line East North East from Baltimore to Mac Arthur? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 22, 2008, 1:53am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/2 "2008-10-22T01:53:18Z")
> [@carnivorousplant](#): > > Southwest flew from Baltimore West out to sea, north east and then north to Long Island. East, dammit. :rolleyes: East from Baltimore, over Delaware, North East grazing New Jersey and then over the sea for a good while, then North for Long Island. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [October 22, 2008, 1:58am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/3 "2008-10-22T01:58:48Z")
Northeast Corridor security? Flight path overcrowding? The pilot was scouting fishing locations? I’m betting the first two, or something similar. ---
**Author:** ![Huerta88](https://avatars.discourse-cdn.com/v4/letter/h/82dd89/32.png) [@Huerta88](https://boards.straightdope.com/u/Huerta88)\ **Post date:** [October 22, 2008, 2:02am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/4 "2008-10-22T02:02:30Z")
I would imagine that most questions about “why’d they route that airline flight that way?” could be answered by some combination of: (1) understanding “great circle routing” ([Great circle - Wikipedia](http://en.wikipedia.org/wiki/Great_circle)). (2) being aware of restricted airspace regions (various military-only corridors and/or you-can’t-fly-over-Camp David corridors); (3) air traffic control considerations (which include not having everyone vectoring in on the same single “most efficient” line at the same time – i.e., building in “planned inefficiency” from lazy indirect loops, rather than possibly-much-worse "unplanned inefficiency from having to have every plane circle the field twenty times at peak hours; air traffic considerations also include whether particular weather patterns/winds favor/allow/require a particular runway approach/approaches). ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 22, 2008, 2:07am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/5 "2008-10-22T02:07:18Z")
Commercial aircraft are flown on airways which are the airborn equivalent of highways. They don’t always go direct, mainly to facilitate separation from other aircraft. Aircraft may also divert to avoid weather, particularly thunderstorms. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 22, 2008, 2:18am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/6 "2008-10-22T02:18:55Z")
Looking at her ticket information, they were ten minutes early. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [October 22, 2008, 2:51am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/7 "2008-10-22T02:51:07Z")
I just read something about this. It turns out airplanes fly from beacon to beacon. They could save billions in fuel costs by flying straight lines using GPS but they’re not set up to do so, and the process of making it possible would cost a lot of money. ---
**Author:** ![SenorBeef](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senorbeef/32/2220_2.png) [@SenorBeef](https://boards.straightdope.com/u/SenorBeef)\ **Post date:** [October 22, 2008, 2:54am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/8 "2008-10-22T02:54:57Z")
I was under the impression planes were allowed to GPS navigate now. If not that’s kind of silly. Regarding beacon “highways”: > **[Victor airways](https://en.wikipedia.org/wiki/Victor_airways)** > > In the United States and Canada, Victor airways are low-altitude airways. They are defined in straight-line segments, each of which is based on a straight line between either two VHF omnidirectional range (VOR) stations, or a VOR and a VOR intersection, hence the beginning letter V (pronounced as Victor in the ICAO phonetic alphabet). > In the United States, Victor airways are designated by the FAA in FAA Order JO 7400.11. They are available for flight below Flight Level 180 (approximately 18,000 ... > **[VHF omnidirectional range](https://en.wikipedia.org/wiki/VHF_omnidirectional_range)** > > Very High Frequency Omnirange Station (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons. It uses frequencies in the very high frequency (VHF) band from 108.00 to 117.95 MHz. Developed in the United States beginning in 1937 and deployed by 1946, VOR became the standard air navigational system in the world, A VOR gr... ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [October 22, 2008, 3:58am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/9 "2008-10-22T03:58:48Z")
And regarding GPS systems: [http://blog.wired.com/cars/2008/04/gps-navigation.html](http://blog.wired.com/cars/2008/04/gps-navigation.html) and [http://www.usatoday.com/tech/news/techinnovations/2008-10-09-nextgen-gps-airlines\_N.htm](http://www.usatoday.com/tech/news/techinnovations/2008-10-09-nextgen-gps-airlines_N.htm) ---
**Author:** ![suranyi](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@suranyi](https://boards.straightdope.com/u/suranyi)\ **Post date:** [October 22, 2008, 4:29am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/10 "2008-10-22T04:29:01Z")
The air traffic patterns to/from Long Island are particularly convoluted. The planes have to bypass the congested airspace around JFK, La Guardia, and Newark airports. Ed ---
**Author:** ![flyboy](https://avatars.discourse-cdn.com/v4/letter/f/4da419/32.png) [@flyboy](https://boards.straightdope.com/u/flyboy)\ **Post date:** [October 22, 2008, 1:39pm UTC](https://boards.straightdope.com/t/airline-flight-path/468998/11 "2008-10-22T13:39:32Z")
Airplanes nowadays have very accurate GPS systems. It’s the ATC structure that’s not prepared to have aircraft flying direct vice airways. I don’t have the jet routes in front of me, but most likely the indirect routing was because of them. Factor in some vectors so they can get clear of the mess of airways/approach traffic coming into JFK, and active runway at MaCarthur to the west or northwest (requiring an approach from the east), and that’d result in what you saw. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 22, 2008, 5:29pm UTC](https://boards.straightdope.com/t/airline-flight-path/468998/12 "2008-10-22T17:29:23Z")
Thanks! CP ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 22, 2008, 11:01pm UTC](https://boards.straightdope.com/t/airline-flight-path/468998/13 "2008-10-22T23:01:32Z")
> [@Bill\_Door](#): > > And regarding GPS systems: [http://blog.wired.com/cars/2008/04/gps-navigation.html](http://blog.wired.com/cars/2008/04/gps-navigation.html) and [http://www.usatoday.com/tech/news/techinnovations/2008-10-09-nextgen-gps-airlines\_N.htm](http://www.usatoday.com/tech/news/techinnovations/2008-10-09-nextgen-gps-airlines_N.htm) Those stories aren’t about GPS navigation, aircraft have been using GPS for navigating for ages (15 years maybe? as long as I’ve been flying anyway), they’re about using GPS derived information to provide air traffic controllers and other pilots with position information on other aircraft, which would then allow for more efficient routing. Australia has been using a version of this called ADS-B for a year or so to make up for its large areas that have no radar coverage. GPS actually has a big flaw compared to ground based navigation aids, it doesn’t easily provide the user with advice that it’s not working. Ground based navaids such as NDBs and VORs have a morse code ident signal that is an audible indication that the station is transmitting. There are methods to determine if a GPS satellite is faulty, but they are far more complicated from a programming perspective than the simple system used by ground based aids. Most IFR aircraft are equipped for navigation with GPS both enroute and throughout an instrument approach, however commercial aircraft with flight management systems (FMS, also FMC for flight management computer) will use a best computed position derived from GPS, AND ground based aids. So the problem is not that aircraft aren’t using GPS, it’s that the airways structure in some countries such as the US are still based on old ground based routes. You still need those beacon - beacon routes for non GPS aircraft and for those times that GPS is not available. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 23, 2008, 1:55am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/14 "2008-10-23T01:55:04Z")
[quote=“1920s Style “Death Ray”, post:13, topic:468998”] Most IFR aircraft [/QUOTE] I Follow Road? ---
**Author:** ![flyboy](https://avatars.discourse-cdn.com/v4/letter/f/4da419/32.png) [@flyboy](https://boards.straightdope.com/u/flyboy)\ **Post date:** [October 23, 2008, 2:46am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/15 "2008-10-23T02:46:23Z")
Instrument Flight Rules, i.e., being able to fly in the clouds or without seeing the horizon/ground. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 23, 2008, 3:03am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/16 "2008-10-23T03:03:19Z")
Operative word being “rules”. IFR aircraft follow a particular set of rules designed to maintain safety in all weather conditions. You can be IFR and not have a cloud in the sky. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [October 23, 2008, 3:05am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/17 "2008-10-23T03:05:05Z")
> [@carnivorousplant](#): > > I Follow Road? It’s a joke from an ancient _Reader’s Digest._ 🙂 Sorry, I thought it was more well known. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 23, 2008, 3:18am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/18 "2008-10-23T03:18:07Z")
I recognised the joke but assumed genuine confusion with the joke being coincidence. Variation, I Follow Rail. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 23, 2008, 3:24am UTC](https://boards.straightdope.com/t/airline-flight-path/468998/19 "2008-10-23T03:24:20Z")
To clarify, I didn’t think you actually thought it might mean “I Follow Roads,” but that you might be using the joke to get more info on IFR. ---
**Author:** ![flyboy](https://avatars.discourse-cdn.com/v4/letter/f/4da419/32.png) [@flyboy](https://boards.straightdope.com/u/flyboy)\ **Post date:** [October 23, 2008, 12:07pm UTC](https://boards.straightdope.com/t/airline-flight-path/468998/20 "2008-10-23T12:07:17Z")
[quote=“1920s Style “Death Ray”, post:16, topic:468998”] Operative word being “rules”. IFR aircraft follow a particular set of rules designed to maintain safety in all weather conditions. You can be IFR and not have a cloud in the sky. [/QUOTE] Yeah, I also thought he may not be kidding, and I didn’t want to even venture into _why_ someone would be IFR in VMC if they didn’t know what IFR even was… [Next page](https://boards.straightdope.com/t/airline-flight-path/468998.md?page=2)