Pages 8 & 9 of the full report have the details of what happened.<p>> … it was found to have encountered an extremely rare set of circumstances presented by a flight plan that included two identically named, but separate waypoint markers outside of UK airspace.<p>> This led to a ‘critical exception’ whereby both the primary system and its backup entered a fail-safe mode. The report details how, in these circumstances, the system could not reject the flight plan without a clear understanding of what possible impact it may have had. Nor could it be allowed through and risk presenting air traffic controllers with incorrect safety critical information.<p>A flight plan came in that had a duplicated waypoint ID at either end of the route. The flight-plan software, when trying to extract the UK portion of an overflight (origin & destination outside UK airspace), ended up focusing on both of those (identically-named but geographically-distinct) waypoints. Software thought they were duplicates, couldn't figure out what the UK portion of the flight plan was, and intentionally crashed. It did so, rather than reject the flight plan for an aircraft that may already be in the air.
As an example of duplicate airspace waypoints ("fixes"): Head over to <a href="https://opennav.com/" rel="nofollow noreferrer">https://opennav.com/</a>, and search "PINTO". You'll find the identifier being used for a waypoint in the United States, in Columbia, and in Chile.<p>In general: waypoints are five letters, VORs & similar are three letters, and NDBs are two or three letters.<p>This is an example of how older forms of identification come under stress in a modern world. It never mattered if you had a duplicate-named waypoint many countries away away; waypoints were defined by intersecting lines (typically relative to two VORs), or by a set distance from a reference point (such as a VOR/DME). Plotting a route would make it obvious how the different waypoints fit in, relative to the start/end and intermediate navigational aids (VORs etc.).<p>But then waypoints started getting GPS coördinates, and were collected into large databases. It's a problem that has been known since it became a problem, but it still causes issues (like leap seconds!).
> This is the root cause of the incident. We can therefore rule out any cyber
related contribution to this incident.<p>They were hacked. Obviously this is the first time this flight path has been filed, otherwise it would have crashed earlier.<p>Phone Phreaking, whilst not technically a cyber attack, is still a form of hacking of phone systems.<p>And email bombs exist which take out email servers and readers, and zip bombs
<a href="https://en.wikipedia.org/wiki/Zip_bomb" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Zip_bomb</a><p>So was this the first instance of a flight path being used as a denial of service and of course the "Blitish" playing down its significance because it doesnt want to offend any one due to its current isolated precarious state?