Morse code is still part of every flight that uses radio navigation. Ground beacons such as VORs, NDBs and instrument landing systems transmit their identifiers in Morse code, and pilots listen to that identifier to confirm they have tuned the right station and that it is working. Aeronautical charts print the dots and dashes next to each station's name, so a pilot does not need to know Morse to check it.
What a VOR sends
A VOR, short for VHF omnidirectional range, is a ground station that lets an aircraft work out its bearing from the station. Alongside its navigation signals it sends an identifier, typically three letters in Morse code, at about 7 words per minute. Many VORs now also identify by voice, but the Morse is still there.
The most famous VOR identifier is probably Toronto Pearson's, YYZ: -.-- -.-- --... The band Rush heard it while flying into Toronto, and its rhythm became the opening of their 1981 instrumental, also called "YYZ". There is more on that in Morse code in songs, phones and films.
What an NDB sends
A non-directional beacon is an older and simpler station: it sends a signal in all directions, and a direction finder in the aircraft points towards it. Each NDB is identified by a one, two or three letter Morse callsign. In Canada, privately owned NDBs use one letter and one number.
What an ILS sends
An instrument landing system guides aircraft down to a runway in bad weather. Its localizer, the part that keeps the aircraft lined up with the runway centre, sends a Morse identifier on a 1,020 Hz tone. ILS identifiers have four letters and always begin with I, two dots, .., so a pilot knows at once that it is a landing system.
At New York's JFK airport, the ILS for runway 4R sends IJFK, .. .--- ..-. -.-, and the one for runway 4L sends IHIQ, .. .... .. --.-. The glide slope, which gives the vertical guidance, sends no identifier of its own.
Why identify at all?
Because tuning the wrong station, or a station that is off the air or under test, can lead an aircraft astray. Listening to the identifier, and checking it against the chart, confirms three things at once: the receiver is tuned to the intended station, the station is transmitting, and its signal is usable. It takes a few seconds, and it is one of the habits drilled into every instrument pilot.
Pilots match the sound against the dots and dashes printed on the chart, so the skill is recognising a pattern, not knowing the whole alphabet. That said, many pilots end up knowing a fair amount of Morse simply from hearing the same identifiers over and over.
Before VOR: listening to the beam
Morse played a bigger role in early air navigation. Some of the first radio guidance systems sent Morse A, .-, on one side of a course and Morse N, -., on the other. A pilot listening in headphones heard A or N when off to one side. When the aircraft was exactly on course, the two interlocked into a single steady tone, because the dashes of one filled the gaps of the other. Pilots flew by ear, steering to keep the tone steady.
You can hear why it works by playing .- and -. one after the other: each one's silence sits exactly where the other has its sound.
Will it last?
Satellite navigation has taken over much of the work radio beacons used to do, and many countries are reducing their number of VORs and NDBs. But landing systems and the remaining beacons still identify in Morse, and as long as they do, every instrument pilot will keep hearing dots and dashes. It is the most common use of Morse code in the world today, as we explain in is Morse code still used?.
Try it
Type any three-letter airport or beacon code into the translator to hear what its identifier sounds like, or slow it down to 7 words per minute in the settings to hear it the way a VOR sends it.