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I understand that five letter intersection codes (such as WARPI, PAPPI, KUBBS, ROSLY, ZALPO, ...) are unique in the world.

However, their names don't comprise a national prefix (as aircraft tail number do, or airport codes do), which would allow to delegate name bookkeeping to the individual countries's aviation authorities by prefix.

Therefore, a single, international organization has to somehow own and disambiguate all the intersection names. I would expect the ICAO to be that organization, but I haven't been able to find any resource mentioning that.

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    $\begingroup$ Intersection codes are not actually unique in the world, unfortunately. There is some overlap between FIRs, but not much. Usually any duplicates are quite far away from each other, but long distance flights mean that they do occasionally show up within a single flight plan. $\endgroup$
    – Greg Hewgill
    Commented May 29, 2020 at 2:22
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    $\begingroup$ Closely related $\endgroup$
    – Pondlife
    Commented May 29, 2020 at 2:59
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    $\begingroup$ is "intersection code" just a synonym for "waypoint name", or a subset? $\endgroup$
    – dlatikay
    Commented May 29, 2020 at 14:32

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The allocation of waypoint names is actually handled by each country's individual aviation authority. This means that there are actually duplicates in different countries or regions. The ICAO has made at least two attempts to remove the duplicates and make the names globally unique, one in 2010 and another in 2018. Despite these efforts, there are still over 1000 duplicate waypoints in the ICARD database.

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As already said in HiddenWindshield's answer, the five letter intersection codes do not have to be unique worldwide. I thought it might be interesting to see how many times these codes are actually being re-used.

Using my current navigation database (AIRAC 2006), I made a search for how many times each code is used. The following histogram shows how many times codes appear worldwide (note the logarithmic y-axis):

Nr of 5-letter code uses

Out of the 124,215 codes, there are 119,973 unique ones (only used once) and there are in total 4,242 ones that are used more than once. The highest number of uses has the code ALPHA with 9 total uses worldwide.

Usually, intersections with the same code are far away from one another to avoid confusion. There are however some quite close re-uses. I searched through my database to find the closest two intersections using the same code and came up with two SIERAs used in Belgium, which are only 18.5 NM away from one another:

Map of Belgium

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    $\begingroup$ @zymhan Neither are part of an airway. My guess is that both of these belong to some instrument procedure (SID/STAR), but for two different airports. Unfortunately, my navigation database does not say to which airport these belong, so this is just a guess... $\endgroup$
    – Bianfable
    Commented May 29, 2020 at 14:57
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    $\begingroup$ Having had a look at them, they are VFR waypoints, unrelated to any specific approach procedure $\endgroup$
    – Jamie Le Bas
    Commented May 29, 2020 at 15:19
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    $\begingroup$ Omg having two VFR waypoints with the same name that close to each other is just downright stupid. $\endgroup$
    – Jpe61
    Commented May 29, 2020 at 16:33
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    $\begingroup$ @Jpe61 almost makes me wonder if its an error in the database or something? or if there was conflicting definitions published at one point that somehow turned into the two entries? $\endgroup$
    – mbrig
    Commented May 29, 2020 at 21:55
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    $\begingroup$ @Jpe61 But such points are not enroutte points, they are reporting points for entering or leaving that specific CTR or ATZ. If enroute, you always say which airport you are flying to in the first place. Only then you care which point you will use to enter the zone. $\endgroup$
    – Vladimir F Героям слава
    Commented May 30, 2020 at 9:30

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