The International Politics of NDB Approaches

A typical NDB antenna installation is as simple as wires strung between telephone poles (background). Often a fan-style marker beacon (foreground) can be found at these sites as well. Courtesy:

How old is the non-directional beacon (NDB) as an aeronautical navigation aid? Eighty years? 90 years? Or maybe more. I’m not sure. The NDB was certainly around before even the fancy four-course range with its dit-dah left-right guidance along a “beam.” But the four-course range died decades ago while the NDB lives on. What’s up with that?

In most countries other than ADF receiver capable of navigating using NDB signals is still a requirement for IFR flight. Newly designed mega million dollar airplanes are still leaving the factory with an ADF receiver, or more often two of them. That’s like including an Underwood manual typewriter along with every new iPad sold. 

But the NDB and ADF live on because of politics, not technology. The “G” in GPS stands for global, and the GPS signals cover the world with excellent accuracy everywhere, not just over the U.S. But GPS is controlled by the U.S. military and that’s why many – even most – nations in the world are still using NDB signals because the NDB transmitter is bolted firmly to the ground in each country.

Example of an outer marker beacon for an ILS. They are often co-located with NDBs. Courtesy:

There is more than the “not invented here” syndrome at work causing many countries to reject GPS for primary IFR navigation, particularly for IFR approaches. It is theU.S.that set the ball rolling when GPS was initially developed.

The original name of GPS was Navstar and it was totally a military project and was created by funds from the military budget. When the first test satellites were being launched in the mid-1970s the U.S. Air Force was very clear that its worldwide navigation system was first and foremost a military weapon.

The Air Force did relent a little by making an intentionally degraded GPS signal available to the public, including pilots, but made it clear that even that lower level of service could be turned off at any time without warning if the military believed there was a valid reason to do so. The Air Force definitely didn’t want any civilian pilots using GPS for primary navigation, much less for IFR approaches flying close to the terrain in the clouds.

The FAA obliged the Air Force and ignored GPS in its plans for the future. The FAA and European aviation authorities invested millions in a squabble over a microwave landing system (MLS) technology that would guide pilots along curved approaches in three or four dimensions. The Europeans wanted to use a Doppler technique for MLS, but the FAA and its industry supporters demanded a time-reference scanning beam (TRSB) technology. The FAA won the fight, but only a handful of MLS systems were ever installed anywhere. Why do I remember this stuff when I can’t remember what I ate for lunch?

Anyway, the civilians in the federal government saw the waste in reserving GPS only for military use when all taxpayers had chipped in to build it. The government changed the policy and assured civilians that GPS signals would be available, and that the accuracy would not be intentionally degraded. The FAA was ordered onboard and GPS became a foundation for the Nextgen modernized air traffic system.

But the rest of the world wasn’t so quick to accept the 180-degree turn by the U.S. government. After all, if theU.S.could reverse its policy on GPS availability once, it could do it again. So most of the world’s aviation authorities simply refused to certify GPS for IFR guidance, particularly approaches. Without GPS all that’s left in remote areas or in rugged terrain where an ILS is not feasible is the NDB approach.

An NDB beacon available from a Russian firm. Courtesy:

The anti-GPS attitude is changing slowly because other nations are launching their own compatible satellite navigation constellations. Europe has its Galileo satellites and the Russians have GLONASS, and I’m sure there are other efforts I have lost track of. It’s not really crucial that these additional satellite nav systems add any capability or redundancy to GPS. What’s really important is that the rest of the world feel a part of GPS and have an ownership stake so they will not be victims of a whim of theU.S.

So the NDB and ADF live on because many national aviation authorities don’t trust the U.S. government, not that they don’t trust the technology of GPS. My ADF receiver is long gone and I sure don’t miss it.

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46 Responses to The International Politics of NDB Approaches

  1. Jake Brodsky says:

    I agree, I don’t miss NDB approaches. I had to do a partial panel NDB approach for my IFR check ride. I may have completed the approach reasonably well, but I feel to this day that there was more luck than skill involved.

    Personally, though I have practiced these approaches, I have not relied upon them except as part of another approach, such as a LOM on an ILS approach. Why these things continue to exist is a mystery to me.

    But just for fun, does anyone want go fly G13? It’s on the L35 chart from MQI to ZOLMN. I’ve done it, but only in VMC.

    • Roger Halstead says:

      Until a few years ago, I used NDBs to file direct. when going to Oshkosh. I’d fly direct GDW, direct Ludington, direct Manitawok , direct to Oshkosh where I’d use the … ILS or VOR approaches. I never had a problem flying NDBs and they are the only thing left that makes a good “ground based” back up for GPS. Soon we’ll have no back up at all. GPS is great, it’s very accurate, and with synthetic vision is fantastic. Problem is, it’s not invulnerable. Some day we are going to regret doing away with all of the ground based systems.

  2. Mike Dempsey says:

    Hmm, partial panel NDB approach, didn’t we rely on the relative bearing to determine on-course or greater than 10 degrees off which meant a missed approach?

    Nonetheless, I didn’t do many NDB approaches in 8,000 hours of flying, most on an IFR flight plan. A friend of mine who is now an airline pilot, explained the NDB approach the best way. It is a way to get below the clouds knowing that an airport is nearby, that is all.

  3. JimC says:

    I wonder if some politics of civil aviation will change after systems like Galileo, GLONASS, Big Dipper (China), etc. have been online for some years…

    Food for thought- the day is coming when the kids in the high school graduating class will not have known a world without GPS.

    Mac, I’m certain that you remember TRANSIT- the daddy of them all. There were certainly some interesting politics behind the origin of that system!

  4. James Williams says:

    NDB is a good back up nav system.

    Simple, relatively cheap, and not difficult to use.

    Pilots are getting spoilt, and losing navigation skills at an alarming rate.

    I prefer the old Steam Gage instrumentation.

    Christmas Tree Glass Instrumentation for reference is fine for airline pilots, but for the little guy?

    We are losing an art here. The art of basic navigation.

  5. Max Trescott says:

    I used to miss my NDB receiver. But now that there’s no longer a classical radio station on the AM dial, I don’t miss it at all.

  6. Kristin Winter says:

    I have retained by KR-87 ADF for three reasons. Redundancy! Nostalgia! SF Giants baseball games.

  7. R K says:

    It is a CRYING SHAME the NDB is so easily dismissed. I’ve been flying for 30 years and teaching for 24. I got my instrument rating before the word “GLASS” was ever considered in connection with the word “panel”. I believe to this day that tracking NDB bearings “TO” & “FROM” the station represents the best mental/orientation exercise any pilot could ever hope to master considering the wind correction involved. Ever try holding on an NDB/DME fix ? Pilots today are too spoiled by automation and are afraid to “work” for something that ignorance quickly discounts as “inefficient”.

    For all you lazy “GLASS” drunks out there I ask you: Would you want your kid to learn basic arithmetic (multiplication & division) with a calculator ?

    The RMI was designed decades ago to help the lazy pilot be more efficient with the NDB however, that is NEVER any substitute for learning the fundamentals. How quickly we forget just how critical it is to first “gather” the dots in order to “connect” the dots.

    Check this out:

    Then watch:

    This incident screams the warning we have all heard yet do not heed: The skills you DON’T USE you WILL LOSE !!! Regardless of how obsolete the NDB is for navigation there is no disputing the workout your brain will get for making the effort and the professionalism those polished skills will demonstrate during enroute navigation and shooting ANY approach to minimums; Or have we become so lazy as to depend on the autopilot/autoland system down to DA ?

    Does (FAR 61.57(c)(1)(iii) sound familiar ?
    “Intercepting and tracking courses through the use of navigational electronic systems”

    If you bother to practice and learn the NDB/ADF/RMI style of navigation you will experience the ultimate sense of orientation and command/authority that is sadly too easily lost in the push-button world of today.

  8. Bob Briggs says:

    I was happy the old Collins ADF was aboard when the GPS failed while landing IFR at Renton from the north near Seattle a couple years ago. The NDB approach saved a hassle.

  9. Stephen Hertz says:

    I don’t miss NDB but you can’t argue that having an NDB aboard provides the most basic of backups. If the whole NAS collapsed, you could still navigate the good old fashioned way as long as AM radio stations survived.

  10. Michael says:

    Ok, NDBs are redundant today. But the iPad’s keyboard is a damn sight harder to type on than an old Underwood. In the old days a average typist could do 50 words a minute on the old Underwood. We can’t do that on an iPad’s softkey keyboard. NDBs are easy to use, even if US pilots have forgotten how. Situational awareness is good with the NDBs, the ADF’s needle always points to the station. Unlike modern glass cockpits, there is hardly any, “what is it doing to now” with NDBs! The beauty of the old systems was that they required the same skill set no matter who made the avionics. The modern GPS based systems all seem to require different commands and are often confusing.

  11. Sidney Wood says:

    On my instrument check ride the examiner made me do the NDB approach three times: The first try, he discovered I was using the panel mount GPS as a cross check. Turn the GPS off and do it again. The second try he saw that I was using the VOR as a cross check. Turn off the VOR and do it again. On the third try he saw I was using the gyro compass, so he put a rubber stick-on over the gyro and the mag compass and had me use the turn needle and clock. No biggie, at least he still let me use the ADF indicator. I always knew where the airport was.

  12. Earl Turner says:

    I cant speak for other countries, but in Canada, politics doesnt play into it (we love the USA). The problem here is that much of the country is beyond range of VOR stations. We trust the GPS system every bit as much as you yanks do, (you still have a VOR reciever in your airplane, don’t you?) but if heading north of Moononee, the backup for the GPS is the NDB. If the NDB is an old underwood typewriter, then the VOR is a daisy-wheel electric. Neither of them will be around for much longer.

    • Mac says:

      Hi Earl,

      Actually, I don’t need the VOR receivers in my airplane because I have dual WAAS navigators, a Garmin GNS430 and 530, and WAAS GPS is approved by the FAA as primary navigation. The VOR receivers kind of go along for the ride because most of us still want to have an ILS receiver and the localizer and VOR receivers are essentially the same. I can’t remember the last time I actually tuned in a VOR because the navigators take me along whatever route or airway on their own.
      I know many pilots don’t trust WAAS GPS as a sole means, but I can tell you that a thunderstorm raging nearby does nothing to that signal, while making an ADF essentially unusable. But I doubt my flying career has enough years remaining to see the NDB go the way of the four-course range.


      Mac Mc

  13. Louie Lacy says:

    When hurricane Andrew blew away the Key Biscayne Vortac they used an ADF with DME and called it Andrew(original). When making the Blufe arrival Miami center asked me where I was going. I told him Bimini I guess the ADF was poining that way because of a thunderstorm. I said what do you want me to do and he gave me vectors for the arrival.

  14. George Groh says:

    Nostalgia isn’t what it used to be, but I remember with fondness the dual adfs we had in the SA 16 in the Far East in 1956-57. I was a navigator in Rescue and was very happy that there was an NDB on Wake Island when we were inbound on a long flight from Iwo. It was a day flight so we had the sun and (as I recall) 2 Loran stations. There were no VORs in the Far East and no radar on Wake. The radar on our SA 16 had been temporarily removed. It only had a range of 50 miles anyway. We made it without incident but the pilots seemed a little anxious . George Groh

  15. Dan W says:

    The Boy Scout motto was and is “Be Prepared.”

    I would want some backup other than GPS for the same reason I highly prize my old-skool map & compass skills… too much dependence on technology breeds complacency, and technological doodads can be rendered useless with relative ease. China demonstrated their ability to knock down satellites, and it doesn’t take a first-world country to build hardware that can either knock out a satellite, disable sensitive electronics, or jam GPS signals. Anyone with basic knowledge of electronics could build a GPS jammer in their garage with parts from Radio Shack and Home Depot. I wish the world were this idyllic place and everyone just magically got along, but there will always be the spoilsports who screw things up for the rest of us. Having a backup plan makes it that much harder for the nefarious few to turn your pleasant day into a really bad one. Also makes it harder for system or component failures to spoil your day.

    I wholeheartedly support the transition to glass cockpits and WAAS GPS navigation… however, I also firmly believe in having robust backup plans and equipment. Single-point failures are not cool.

    Preparedness is the difference between panicking when that which you rely on goes haywire, or coolly reverting to Plan B.

  16. Jeff Tyler says:

    Mac, we in Alaska still have our old-style FSS’s in addition to our NDB’s and we love ‘em both. That which works for you folks in the Lower 48 isn’t necessarily the best approach to get the job done up here. I love my GPS, but the NDB provides a cheap back up.

  17. Jeff says:

    I still have a NDB in my plane and I still practice approaches with it, in fact I did one last Friday night. I haven’t the extra money for an IFR GPS, so I rely on my VOR, NDB, and portable GPS. I’m making do with what I have

  18. Guy Lapierre says:

    In the aviation business, reliable back up is the way to survival. ADFs is still, for those who have kept their skills alive a way to stay “airborne” in the good direction .

    • Bill Larkin says:

      The Australian Government is phasing out the NDB’s here ,however I believe this is a mistake as they can be a life saver if the GPS fails.

  19. Christopher Roberts says:

    I don’t agree that politics or mistrust of the US is the most prominent reason to maintain NDB’s. It’s much more to do with the additional safety of ground-based navigation aids. They are relatively inexpensive to maintain for the benefit they provide.

    It appears we will have to do without them as they are withdrawn around the world, but I don’t understand pilots who would apparently rather not have a simple, cheap back-up system, and that attitude has accelerated their lamentable decrease in number.

    It seems to me there’s more penny-pinching politics involved in removing them than keeping them!

  20. Christopher Roberts says:

    I should also add that I don’t understand the reticence to adopt GPS navigation, for exactly the same reasons!

  21. Steven Wolfe says:

    Despite the limitations an NDB approach has, it IS a back-up that is better than nothing.
    GPS satellites have not been around all that long in the grand scheme of things. It will be interesting to see if a massive solar flare will knock these satelites out. If this happens, then we’ll be back to flying between bonfires without any other form of ground based navigation aids.
    It all comes back to being able to safely continue, despite a single point failure. All IFR panels should be designed with this in mind. Despite losing a screen, a power source, or an antenna, there should be a good alternate means of finding your way.
    For VFR flying, I’m a fan of good old fashioned map reading. That always works!

  22. Mac says:

    Believe me, I’m all for backup and redundancy. But I wonder how many pilots who appear to be very worried about avionics failures–GPS or otherwise–fly with only one engine? I guess we all choose what we worry about most.
    Mac Mc

    • I’m not sure what happened to my original post, but I’m one of those pilots who flew with only one engine out front. I flew IFR in the clouds, (rain or snow) as long as I did not have to worry about ice or thunderstorms and I’m quite willing to work my way around scattered thunderstorms. I always kept my NDB skills up. One instructor had me do a descending hold on an NDB. It was a 1000 feet per circuit and it took 5 or 6 circuits to get down. BTW this was with a very strong cross wind to the hold and approach. Afterward we checked how I did on the Garmin. It was virtually one track with only minor deviations .

      As I said before, I love GPS. It lets me fly with a precision no other instruments can match. I used to use my yoke mounted Garmin for virtually everything and it was legal because I had real RNAV (KNS80 not GPS) But GPS needs to be backed up by a completely independent system and not another country’s system. Short term GPS is very reliable. Long term it looks pretty fragile and susceptible to Coronal Mass Ejections, or CMEs.

      LORAN would have been the ideal back up for GPS. No it’s not as accurate, but many it was decommissioned and destroyed in a very short time to make recommissioning it impossible.

      In an emergency the NDBs like LORAN allowed for creating your own approach. It may not have been legal, but the old “any port in a storm” held true. I’d quite happily argue the legalities after safely down.

      We really need a ground based back up for GPS.

  23. A good portion of the FAA owned NDBs have been decommissioned. A majority of those still out there, at least in then western U.S., are owned by local governments….state, city, or airport…and the FAA does not have unilateral jurisdiction over keeping them on the air. I suspect those non FAA NDBs will be around for many more years because they are paid for and cheap to operate. However, the FAA is not necessarily keen on maintaining the SIAPs that use these NDBs, especially when there are RNAV SIAPs available to the same runway. There is a great deal of budgetary pressure on the FAA to reduce its part of the cost of maintaining the airspace system, and retaining SIAPs that are rarely used is certainly among the low apples on the tree.

  24. Jeff Tyler says:

    The NDB provides the Transcribed Weather Broadcast here in Alaska. That’s yet another service that has been mostly abandoned in the Lower48, but lives on up here, happily. In some instances that TWEB is the only source of weather info available on the ground prior to flight if one doesn’t have a sat-phone.

    I too like my high tech devices. But sometimes high tech doesn’t get the job done.

  25. Alex Kovnat says:

    Politically-forced reliance on automatic direction finders and non-directional beacons in many countries, is not only frustrating but dangerous. Back during Bill Clinton’s administration, a member of his cabinet was killed in an aviation tragedy that occurred when a Boeing jetliner hit terrain while the captain was attempting an NBD approach. That’s what I understand happened; feel free to correct me if I’m wrong.

    It would be nice though, if we here in the USA were to implement accuracy-enhanced Loran as a backup to GPS. Another possibility that avionics enthusiasts should consider is radar or radar-like systems (i.e. MLS-type landing systems) using 35 or 94 GHz. The latter has been used experimentally on helicopters for landing on terrain where rotor downwash kicks up clouds of dust which block the pilot’s vision.

    • Randy says:

      Would that we could. Too late to do anything about it. The administration has bulldozed most, if not all, of the Loran sites to save an estimated $36 million per year. By doing so, much of the rental fleet, which was equipped with Loran is now carrying around useless boxes in their panels. Many of those owners do not have the cash laying around to install GPS. Hand held GPS can be a good help, but they don’t interface with autopilots. It’s a shame that our leadership is so short sighted. Virtually none of the rentals that I’ve used had GPS in them. Finally getting some, but the costs are higher.

    • There has been quite a bit of talk about pilots in other countries relying on their advanced avionics and not being well skilled in basic airmanship such as unusual attitude recovery. Is the NDB navigation and approaches still taught and practiced in the larger jets?

      It matters not your rating. If you are “trying” to fly an NDB approach you shouldn’t be. Trying indicates lack of proficiency and I believe that was the case.

  26. Pingback: The Dreaded NDB Approach | High Altitude Flying Club

  27. john wasdin says:






  28. john wasdin says:


  29. Alex Kovnat says:

    John, the acoustics in this forum are excellent. You don’t need to shout. We can all hear you without using shout mode. Please, use lower case letters a little more.

  30. john wasdin says:

    sorry! i don’t twitter or facebook or any other such thing. my phone is for talking not texting and therefore i forget that caps is for shouting. in the old school of typing versus texting caps is for making something stand out versus shout. i guess billboards must be screaming by these standards.

    steamgauge john

  31. john wasdin says:

    also curious; how in the first 6 comments they typed so small that it’s hard for me to read (old eyes i guess). they must be whispering (old ears can’t hear).

    sorry couldn’t help myself.

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  33. Pingback: GPS & NDB – The International Politics of NDB Approaches | COPA-BR

  34. Pingback: Porque as autoridades aeronáuticas têm tantas restrições ao GPS « Para Ser Piloto

  35. Erin says:

    Not a pilot, or off shore rig rough neck, just curious, and always learning. Now, my phone isn’t the most reliable this ever, nor is my garmin, or my tomtom. Bad weather, in the sticks, much less in the middle of the Gulf of Mexico, could all effect the relay in my gps. Doesn’t that count for something when it comes to the NDBs?

  36. Nereida says:

    The combination is poised for physical perfection.

  37. hey says:

    I really like looking through an article that can make men and women think. Also, thank you for allowing for me to comment!|

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