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ADF Approaches, gone or is anyone still flying them?


JohnB

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2 hours ago, M20F said:

GPS can and does supplant anything you need an ADF for both practically and legally.  You would put the fix CAT in your GPS, set OBS, and hit OBS (on a Garmin product anyways) and fly the hold.  No need to have an ADF in the plane to fly that approach legally or otherwise.

I can understand the number of people saying they would never want to fly a NDB in IMC because the options today are so much better.  Not so long ago though the only way into a lot of airports was through an NDB approach and I never found them to be any worse/better than a VOR/VOR-A approach.  Certainly not a precision approach but not a bad option.

Well not exactly everything! I am sure you didn't mean it, but there are some out there that hear that and think GPS is good to use on the final approach course of NDB and VOR approaches which of course is not true unless the approach is named "VOR or GPS  ..", or "NDB or GPS ..."; everything else yes.

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21 minutes ago, DonMuncy said:

What is "Head always falls/tail always rises." I haven't heard that one.

that is a saying that allows you to fly a course rather than homing.  It helps knowing which direction to turn.  Knowing that the head of the needle will always fall you can make a heading correction to  maintain course, you need to put the aircraft heading in a direction that will allow the head to fall to the course while inbound or the tail to rise to the course if outbound.  This was generally taught with mental visual as well....picture your wife/girlfriend bending over to pick something up....head falls-tail rises.

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2 hours ago, kpaul said:

How fast is your airplane?  I have flown numerous NDB approaches in both the C-130 and PC-12, and unless I am mistaken both aircraft are significantly faster.  Even at 150 KIAS you should have no problems flying a full procedure NDB from any approach direction.  All that being said, given the choice, I would fly any other approach rather than a NDB.

I normally fly approaches to the FAF at 120.  I am sure if I practiced some NDB approaches I could get the hang of it again, but I am not very motivated to try because I never see one in real life.  There is always an ILS or an RNAV.  So about once a year I go out and fly one just to see if I can do it.  The problem for me is making a turn of that size and then getting back on the NDB backcourse while having to do all the mental math and making a wind allowance that is really unknowable until you have flown the back course for awhile.  Doing all that, getting on the back course, and staying within 10 miles is way too much work. 

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I agree an ADF/RMI only approach is the most challenging approach left to fly.  The most challenging portion for most people is that the needles lie in the turns so you can only get an accurate reading while wings level.  I initially learned to fly NDB approaches using an ADF head similar to the picture below.  It was challenge to tune, so it already pulled your cross check away from the primary flight instruments and additionally it had inherently unstable needles that seemed to wander even when holding a steady heading.  Even with two separate receivers dialed up to the same station there was generally 5-10 degrees of difference between each of the needles.  The aircraft I fly for work (PC-12) has the ability to display the NDB approach on the HSI which basically makes it a less accurate VOR approach.  There are quite a few NDB's still active that I know of to include Apalachicola FL (KAAF), Little Rock AFB, AR (KLRF), Helena MT (KHLN), Craig Field, AL (KSEM) to name a few.  You have to actively search them out for the most part and each of these fields has another approach that is significantly more accurate.  I like flying NDBs while VMC just to sharpen my cross check along with stick and rudder skills, but in IMC I'll take a RNAV or ILS/LOC any day.

narco.jpg

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4 hours ago, M20F said:

I can understand the number of people saying they would never want to fly a NDB in IMC because the options today are so much better.  Not so long ago though the only way into a lot of airports was through an NDB approach and I never found them to be any worse/better than a VOR/VOR-A approach.  Certainly not a precision approach but not a bad option.

I found there to be a difference between an on-airport NDB approach and an off-airport one. On airport? Not too hard to do it right and worst case scenario doing it wrong is you are homing in; not much of a problem unless there is a ridiculous crosswind component to the approach.

But off-airport for any real distance? Flying an off-airport NDB 8 miles to the runway with DG off by 3° but everything else, including your technique, being perfect, puts you almost a half mile laterally away from the runway at MDA. I mention the 8 NM because that was the off-airport NDB at my old home base, and everything else was rarely perfect.

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Just now, midlifeflyer said:

I found there to be a difference between an on-airport NDB approach and an off-airport one. On airport? Not too hard to do it right and worst case scenario doing it wrong is you are homing in; not much of a problem unless there is a ridiculous crosswind component to the approach.

But off-airport for any real distance? Flying an off-airport NDB 8 miles to the runway with DG off by 3° but everything else, including your technique, being perfect, puts you almost a half mile laterally away from the runway at MDA. I mention the 8 NM because that was the off-airport NDB at my old home base, and everything else was rarely perfect.

For most NDB's the minimums were such that once you got onto the approach you were out of the soup or were shortly thereafter and then it was just a matter of the eyeballs finding the airport. 

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2 hours ago, kpaul said:

that is a saying that allows you to fly a course rather than homing.  It helps knowing which direction to turn.  Knowing that the head of the needle will always fall you can make a heading correction to  maintain course, you need to put the aircraft heading in a direction that will allow the head to fall to the course while inbound or the tail to rise to the course if outbound.  This was generally taught with mental visual as well....picture your wife/girlfriend bending over to pick something up....head falls-tail rises.

God, I hated that saying!!! And personally, I turned the wrong way as often as I turned the correct way. That's being kind to myself. I turned the wrong way much more often!

What eventually happened (before GPS became truly ubiquitous) was that I was working on my double-I. I had a friend I flew with monthly for currency and dinner who was also terrible at it (the only person I even know who was actually good at it was my CFII - I hated him for it!).

Trying to find a solution, I eventually settled on one. Whether you think you need it or not, periodically turn to your on-course heading. Whether inbound or outbound the needle will point to the course. Straight ahead or behind, you are on course. To the right or to the left, that's the way you need to turn to correct. No riding or falling needles. My friend started flying them great. I,OTOH, turned out to be a much better teacher than pilot :D

 

 

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  • 2 weeks later...
On 12/11/2015 at 2:48 AM, JohnB said:

Wow... did you remove your ADF antenna as well or just the receiver and indicator?

Yes... good point Paul., I was wondering if there are airports with only an NDB approach, and so far, dont see any in the US. Mexico yes? But you're right, wouldn't ever want to fly an NDB in real IMC, and even worse in Mexico!

Wow.. that looks like a fun approach! Looking up, this airport has a GPS and an RNAV approach, so wouldn't be necessary. but may be fun

All HUGELY helpful everyone. Gracias!! Ok unless I really want an AM radio, ADF is going bye bye. Thanks again!

I thought the avionics shop was removing the ADF and the antenna/wire but all they removed was the actual radio.  Before I paint it I'll remove the antenna and fill any holes that it leaves.

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