ADF Receivers....Gone the way of the dinosuaurs???

[SASless]

Of late, my engineering staff have been trying to convince me that ADF receivers are a thing of the past.....based upon the lack of technical support and spare parts for the ones we have installed on our two aircraft. They suggest when we refit the aircraft with "modern" panels and radio's we should omit installing any ADF receiver.

What say ye?

[NickLappos]

GPS has my vote, if I were spending my money. But the full published ILS still needs an adf from time to time, and so do small fields in far away places.

I would trust a good GPS over an ADF, anytime, if legalisms are not the issue.

[Another KOS]

GPS when it has a co-located (and cheap) INS.

[flygunz]

You may know this but the worlds most potent attack helicopter still comes with an ADF as standard. It's always been consistent in pointing the way to the bar and for picking up the sports channel on a saturday afternoon for the football, sad day if they were to be thought of as redundant.:ok:

[SASless]

If the two ILS approaches in our area have LOM's, can we use the GPS to mark them if on an IFR flight in IMC conditions. (In reality yes....but legally???) Of course , that assumes our navdata cards are current.....and all that.

[GLSNightPilot]

Yes, you can use the GPS legally, according to Jeppesen and the AIM, to fix VOR, NDB, intersections, or whatever else. In fact, using the GPS, the VOR or NDB doesn't even have to be working - the authorization specifically says the facility may be inoperative, and the GPS can still be used to fix it.

But if they take out the ADF, how will you be able to listen to Paul Harvey and Rush Limbaugh? Our pilots would cry and whine forever if the ADF were removed, and it's the first thing they'll write up in the book as inop. :rolleyes:

I seldom if ever use the ADF, and LOM's are being decommissioned at a growing pace. Soon there will be few, if any, LOM's in existence in the U.S., and any excuse for use of ADF will be gone. My main complaint is that I still have to demonstrate testing the ADF during checkrides, even though it won't be used for anything during the ride, & the only thing it's used for on the line is listening to commercial broadcasts with the needle parked. I don't have the time or inclination for that, so I'd prefer it to be gone.

[NickLappos]

GLS,
Its good that we have Rush Limberger, because otherwise somebody might think America was settled with sentient beings.

[SASless]

Errrr....Nick....I am getting old but I do not have to wear diapers yet.....sentient I ain't yet!

[Flight Safety]

Question: When the LCD PFD fails (one or both depending on the aircraft), what do you back it up with? Answer: A backup artifical horizon, airspeed indicator, and heading indicator.

Question: When the GPS unit (or screen) fails, what do you back it up with, when you're using it for primary navigation in IMC conditions? Answer: It seems to me you'd back it up with VOR, DME, and ADF (along with radar directed ATC when it's available).

Why lose the ADF when it might be needed? Comments are welcome.

[SASless]

Prior to GPS.....as my memory serves me....the radio configuration ususally consisted of dual coms, navs, single adf, single transponder. If we use the same concept would we not have dual GPS such as the more serious EMS operators do?

[Blue Rotor Ronin]

Why remove a nav aid?.. in a Supa dupa puma if both alts fail you're left with an ADI and an ADF. Some places outside of the mainland A/D have little option as radio 5 live is bairly receivable from anywhere else.....:ok:

GPS is UNreliable.....(regardless whether ADF's point at you're nearest TS...) as it has a seemingly infallibility about it... :ok:

[GLSNightPilot]

SASless, I hope you're still sentient. You don't write as if you're senile. :D

FS, we still have to have 2 VOR's to operate offshore. They're useless out there, but they have to be operational. If the GPS fails, we can just fly north until the VOR's start working. With the ADF, we could home to New Orleans, I guess. :p

[EESDL]

Always grin when the old chestnut of GPS inaccuracy/reliability raises it head.......The ADF is infamous in it's inaccuracy, even to the extent of being a prime question in the exams. The ADF relies on one transmitter (with no back-up), whilst we are all aware of the numerous sources for the GPS.

After spealing out the pneumonic for all the errors, had to scratch my head and wonder why we still used the thing, procedurally.

When will people latch on to the fact that, apart from the pilot, the ADF is the most inaccurate and unreliable direction aid in the aircraft?

It is also just as easily 'jammed' as the weaker sat signals.

Sounds to me that anyone who still extolls the virtues of the ADF (apart from getting the cricket scores) also hails from the same cadre of drivers who insist on the push-pull method of steering a car!! (OK, so I get the Telegraph, doesn't make me a bad person)

[S76Heavy]

Offshore on the North Sea, most of the platforms have an NDB to back up our Airborne Radar Approaches. If the GPS packs up. that is the only way to identify our destination.
Furthermore, I find the ADF very useful in keeping me awake during flight, but also to alert me to possible lightning via the change in static. At least that's my excuse..:D
So we won't be removing them just yet, I hope..

[Steve76]

What am I to listen to the radio with?
Or find thunderstorms....
Or watch copilots turn the wrong way.....;)

[Blue Rotor Ronin]

I admit that the ADF has a penchant for The Big Clouds, HOWEVER, why remove a Nav-aid. Especially when CB's are not the only baddie, satellites are extremely sensitive to solar storms, although its highly improbable that a single Big Daddy would remove all 24 or more.
On a more realistic note, not only does the RAIM on the GPS fail fairly often, it sometimes doesn't indicate that it has. If you've ever gone into that autopilot rate one turn whilst both of you look at each other with the infamous, what the F!?k was that!, and realised you're 2 miles of course in zero viz in a very busy North sea, the VOR's no use to pilot nor beast, sooo.... in a TS free moment you check you're ADF radial and take the appropriate action. Not only can it save your arse, it can increase your airbound pleasure by being able to announce to your Scottish pax that England have won the odd sporting event. Why remove such glorious diversity.:ok:

[Shawn Coyle]

So, if your IFR approved GPS does something to you that you didn't think it should, like not tell you it's lost when it's lost, what do you do?
Don't you think you should tell someone like the manufacturer, the civil authority, possibly the air traffic control people so that these things can get monitored, and possibly someone might fix something if enough of it goes bad?
Service Difficulty Reports - send 'em in. Enough people send these things in, it will get noticed.

[Winnie]

Now I have to use my expertise here as it seems obvious that you are all confused????
NDB/ADF gives BEARINGS, whilst VOR's give RADIALS, or did I loose something through my training???

Now this was meant humorous, but I'll take my beatings in stride:} Hope to be with you out there in the dark foggy norwegian sector soon!!

[Flight Safety]

Winnie, you're correct. I think you could technically fly a reasonably good radial with an ADF by manuvering to maintain a steady bearing, but it wouldn't be as accurate as a VOR radial.

[ShyTorque]

Of course, here in old blighty we aren't allowed to use this new-fangled GPS as a primary navaid, can't be right.....

ADFs are much better, don't you know, her-grumphhh, mutter mutter, CAA mutter....bring back Decca....and the sextant....:rolleyes:

[Flight Safety]

ShyTorque, nobody is suggesting we shouldn't go forward with better navigation technology (i.e. GPS). The issue is the inability to go backwards when it might be needed.

GPS technology is great, but VOR/DME/ADF technology is still good. I'd like something "good" to fall back on if "great" fails.

[ShyTorque]

FS,

:ouch: No, and I agree.

Sometimes our english humour is misinterpreted by you chaps further west. I was (rather obtusely, I agree) drawing attention to the fact that in UK our IFR rules are different. We are NOT allowed to use GPS as a primary navaid instead of radio beacons, only as a backup. The post from GLS about using GPS waypoints in lieu of a serviceable beacon is NOT valid in our part of the world.

In fact there has been a very recent proposal by the CAA to legislate against "unpublished" approaches at airfields. This appears to be aimed at outlawing GPS letdowns.

Things will undoubtedly change one day but we do seem to lag behind the rest of the world in some respects.:ok:

[Blue Rotor Ronin]

Bearing, radial, forgive my looooose english ( don't worry, it's better than my Norski) why remove a Nav-aid that weighs less than your lunch. It's a back up. And a neccessary one.:ok:

[GLSNightPilot]

Maybe it's necessary over there, but in the U.S. it isn't even useful. There are no beacons offshore, and fewer every day inland. If I lose my GPS, I still have 2 (count 'em, 2) VOR's. If I lose all these, I still can't use the ADF for much, because there are no ADF approaches near the beach. I can, however, fly north until ATC can hear me, & get a radar approach at many airports. The ADF costs money to install, & much more to maintain. Our avionics techs spend a lot of time fixing them, & replacing parts. That money could be much, much better spent on something more useful & more likely to save my butt, like TCAS or another GPS or almost anything. I have in my shirt pocket a computer more powerful than what is on the space shuttle, & it cost less than $US300. Technology moves on, & old technology becomes obsolete. Get over it.

[ShyTorque]

GLS,

I am well over it personally, but our regulatory body aren't. :(

We still have many NDBs in UK, using them is the only legal way to let down to a lot of our minor airports because that is the only published letdown. Many of us do have the capability to let down much more accurately using GPS but aren't legally allowed to do so.

I hope this changes soon; it's high time we were allowed to take a giant leap into the latter part of the 20th century.

[SASless]

Shy Torque....Why will the CAA not approve the use of GPS as a primary form of navigation? The FAA does...and we have approved GPS approaches that approach ILS accuracy.

In Nigeria, when the Nigerian CAA mandated the installation and use of GPS, Bristow management there made the enlightened statement..."ok fine, but when they go U/S, that is the end of it...we will not repair them!" They had taken the attitude that GPS purchase "just wasn't on, old chap!"

[Blue Rotor Ronin]

Gls, that's fine and dandy that your'e able to receive VOR's offshore and have no rig NDB's , however we do. GPS is fallible and DOES fail. The one thing the ADF has, short of 5 live is range and a low power drain in the event of a double ALT failure. The FAA may feel they are remarkably progressive as they own the goodies, however machinery does fail as does your licencing authority, just look at the medical and exams for pete's sake, unfortunately technology only accounts for so much. Get with it as opposed to over it. (saucer of milk, table two!):ok:

[rotorboy]

GLS,

Intersting you talk about the cost of Nav Aids. Did you know that a new ILS cost over 1.2m to install. With the advent of WAAS technology a new GPS approach in the next couple of years will cost under a couple of thousand, to get approved an published. If you dont want it published , all it will cost is the cost of the box.

Within the next couple of years I bet the Approach plate book for your area looks like the FAR/AIM (well it will all be digital, wont it, heck you can get that nifty new UPS stack with map, plate dispaly, nav/com and xpndr for 10k or so).

Ah now my point, if you look, many VOR approaches are staring to go away as more places get Rnav/GPS apporaches, the vor's are so expensive to maintain. It is the NDB's they leave, they are simple and cheap to keep up.

I agree, why get rid of something when it is simple (a little crude, but so are most of us), and a viable backup. Hey and I am like you I dont go anywhere with out my 300 dollar Garmin Pilot 3, works better than that damm bednix, plus it has big buttons.


RB

[ShyTorque]

GLS,

I understand that the UK CAA are unhappy with the thought of an inexperienced pilot pushing his luck too far by trying to let down to his farm strip in 8/8 with only a portable GPS on his lap.

The other concern is that GPS has no alerting system for the real time accuracy of the system, particularly in view of the fact that the whole system can be deliberately degraded. I think this is somewhat unreasonable in view of the well known inaccuracies of NDBs. As we know, these also have no warning of failure (apart from the cessation of the ident) but are still the only letdown aid at many UK airfields (beware that frozen ADF needle once you're inbound to the beacon :uhoh: , although not a problem for me because I have never managed to peg that bloody needle yet....).

My own view is that we should move forward with GPS technology asap. In truth the CAA in some respects probably want to achieve this just as much as we do but the problem is that to do so costs money.

As we all know, the CAA are required by government to be self financing. Seems to me that perhaps (unfortunately) for now the cheaper option is to keep the status quo (or our medical and licensing costs will have to go up again :ugh: )

Having said all this, I would be very sorry to see NDBs ever removed for some of the (navigation) reasons already stated. Despite having an FMS to fly on I always tune to an appropriate one as a backup, even when using VFR. I can't say we ever get much chance to listen to the cricket scores though ;)

[The Nr Fairy]

ShyT :

As in here ? http://www.aaib.dft.gov.uk/bulletin/apr03/n961jm.htm

I know it's not rotary, but a salutary lesson all the same.

[GLSNightPilot]

Rotorboy, I don't think it's true that VOR's are being abandoned while NDB's are being maintained. A look at the Jepp NavData notams shows a long list of NDB's OTS or decommissioned, few if any VOR's. LOM's are being decommissioned at a fair clip.

Shy, GPS does have an alerting system - that's what the RAIM alert is for. However, I don't see what NDB's have to do with idiots drawing up & flying their own approaches. Sounds like you (or the CAA) want to do away with GPS just because someone abuses it. N.B., pilots have flown unauthorized NDB approaches far longer than GPS, since the NDB's have been around far longer. Removing ADF receivers from offshore helicopters, or EMS helicopters, has nothing at all that I can see to do with this.

If your operation requires an ADF, by all means keep it. But in another part of the world, where it's of no practical use, why argue for keeping it? Do what you need to & let others do the same, is my opinion.

[ShyTorque]

GLS

Please actually read other people's posts before you go blagging off about them, especially the third paragraph of my last one :hmm:

FYI, I use GPS every working day and have done for years. My job would be much more difficult without it. I am very much pro GPS, as is anyone with any experience of it. Where on earth have you got the ridiculous idea that I or the CAA "want to do away with GPS?". I merely pointed out the UK regulations, that's all.

I am aware of the RAIM error system and have to sort it out with FMS but of course not all GPS units alert the user to it. As I said, from what I have gleaned, it's not so much the pro users that the CAA is concerned about.

BTW, without radio navaids I would be very interested in your personal IFR backup plan in case your aircraft's GPS failed.

[GLSNightPilot]

Shy, I did overstate the case. I saw the part about your being for GPS development, but still don't understand the connection with the CAA's worries about unauthorized approaches and ADF.

Don't know about the UK, but to be certified for IFR in the US, any GPS unit is required to have RAIM capability. If it doesn't provide the warning, it can't be used for IFR. I would assume the same requirements exist under JAR.

In order to launch IFR offshore using the GPS, I'm required to have 2 VOR's, and both must be operational. My plan if the GPS fails is to dead-reckon to where ATC can talk to me & get radar contact, about the same time I would start picking up VOR signals, perhaps later. Exactly the same plan with or without an ADF, since the ADF won't help me much here. I could home to a commercial AM broadcast station, but to what point? I would then fly the ILS to my home base, which has no LOM, thus the ADF would be of no help.

[ibgutless]

Some have made a few statements that are not “completely” correct, so not to point a finger. Some light reading for those “I gots to knows!” (remember Dirty Harry, the man had to Know) type Pilots, try this link: http://www.trimble.com/gps/ . Question: Which is the more accurate INS, GPS, VOR or Loran C? I think you will be surprised. Does GPS have or need a Ground Station? What’s Lnav and Vnav?:confused:

[Another KOS]

It is my understanding that:

Part 135 requires 2 independent receivers for navigation. During the enroute phase if the aircraft can be safely navigated over the same route using GPS, and independently using LORAN, VOR, or ADF, the navigation equipment would be considered appropriate to the facilities to be used (i.e. a backup is necessary and due to the potential of common interference, the backup cannot be another GPS).

(Over the North Sea, in areas where there is a lack of navigational coverage from ground based aids, the operator must have procedures in the operations manual to mitigate any failure of the GPS en-route.)

In the US, if an airfield is served by just a GPS approach and the aircraft has a GPS with another type of backup navigation system i.e., VOR, VOR-DME and GPS becomes inoperative, no approach can be started. However if that airfield had GPS and VOR approaches and the GPS went down, either before or during the approach, the VOR could be used for track guidance or for the VOR approach.

If the destination has no ground-based aids, a non-GPS aid would be required for the alternate airport. If a failure of the GPS occurs, the aircraft must execute a missed approach, climb and re-enter the system by navigating to ground-based facility. It is essential that, in the case where the missed approach is due to a failure of the GPS, the go around can be flown safely without track guidance (many US missed approaches and SIDs are based upon heading information and therefore no track information is provided to the pilot).

It is unlikely that any State is opposed to GPS, however, one has only to observe the (subtle) changes of attitude in the US following the publication of a number of important reports (the John Hopkins, the Volpe etc.), to see that this is a complex matter that requires considered policy.

Modern Safety Management Systems has forced hazard analyses to be conducted for any new equipment/principle/method/procedure. This was not the case when DECCA was adopted as the navigation aid of preference in the North Sea.

GLS: it is not JARs that prescribe the standards of equipment it is TSOs - which in this case is a common text used by most States.

My contention is that the best solution to these problems will come with the co-location of GPS and INS in a single and inexpensive box (my understanding is that the BA609 is today flying with such a system installed).

It is also my undertanding that:

Any proposed amendment to CAA regulations on descent below the MSA, is probably based on the need to remove the anomaly of the wording that permits the descent when on an 'approach to landing' (my words not theirs but you will see the point). The present wording does not require this to be 'on a published procedure' - with the obvious potential for 'home grown' procedures. (There was also a recent amendment to JARs to permit a descent below MSA in accordance with procedures accepted by the authority - this was to provide a facility for an en-route descent over the sea using the Radar to provide obstacle clearance.)

There was representation to the CAA during the discussions on this change to ensure that, when closing this loophole, operators' 'discrete procedures' (contained in the operations manual, or the Jeppersen or the AERAD) would still be permitted - including generic ARA procedures.

[GLSNightPilot]

Another, it's my understanding that a TSO just states that equipment meets certain standards. It's up to a government agency to require that the equipment meet those standards. Not all GPS receivers meet any TSO, and it's quite legal to use those receivers for some things. I have a handheld backup that I carry, & often use on the ground. It meets no TSO, nor is it required to. I could use it for IFR flight, but the FAA forbids it. It's the FAA that requires the equipment to meet the TSO. If I'm in error on this, please point me to the correct documents.

[Another KOS]

GNS:

Not exactly an expert on this subject but:

TSOs are an umbrella document that usually reference technical documents produced as guidance by such organisations such as RTCA, EUROCAE etc (committees for offshore safety have also been active in the production of technical standards for survival suits, lifejackets etc. that will be accepted as JTSOs).

The requirement for the application of TSO is contained in requirements; JAR-OPS is one such and makes statements such as "...minimum performance standards are those prescribed in the applicable JTSO (the JAA equivalent to TSOs - TSOs are also acceptable), unless different performance standards are prescribed in the operational or airworthiness codes". This applies to all instruments, equipment, communication and navigational equipment etc.

To be part of approved equipment GPS must have been approved - both the functional and build standard and the fit.

The question that was posed by SASless exemplifies the quandry of the modern world where technology moves faster than the mind of the regulator (or his processes). This is exacerbated by the requirement (as stated in an earlier post) for technical assessment of operational requirements and hazard analyses.

As far as I am aware, the regulations for navigation aids operates in the area of 'deal with what you understand'. Thus most regulations prescribe the aircraft equipment and say nothing about the ability to receive the signal (as you pointed out with your perceptive comment on VORs). The fit for IFR offshore operations is a good example of anacronistic regulations in some States.

What would be better is an objective regulation that deals with these issues (state the objective for the navigation equipment and permit alternative methods of compliance). FAR 135.165 appears to deal with that quite well as does JAR-OPS. ICAO is in this respect objective but does require that, if the equipment that is being used for navigation fails, alternatives are available.

We have to solve the problems of GPS signal and equipment reliability. As stated earlier, redundancy at the box level (GPS + INS in a single box) is an answer - particularly for safety critical applications. (The ongoing debate is more about continuity and security of signal than aircraft equipment.)

The problem that operators face is the need to have helicopters equipped for multi-purpose activities (it is after all a (nearly) once-and-for-all choice).

[ShyTorque]

GLS NP,

You said that you can't understand the connection between unauthorised approaches and ADF. I'm not actually sure what your statement means so excuse me if I'm talking at crossed purposes.

However, to try to put my point another way; a GPS letdown can be attempted anywhere, whereas an ADF letdown can be attempted only where there is an NDB. In UK there are NO GPS letdowns that are aproved by the CAA because at this moment in time, GPS cannot be used for primary navigation, even when flying VFR.

There is an official letter published by the CAA which outlines their concerns about the possibility of lack of accuracy of the GPS system; it states that not all GPS equipment, previously sold and used for aviation, has RAIM. In particular, most lack RAIM / FDE.

Such aircraft equipment hence is incapable of cross-checking and maintaining it's own accuracy, as FDE is designed to do. Also, even if FDE is fitted, it may not be available, because of the incomplete network coverage for the requirement to have 6 satellites in view to allow it to work.

The UK onshore circumstance is quite different to offshore ops in that there is a very major requirement to avoid the many and very adjacent bits of airspace that need to be avoided. Your plan of a DR plot until you got VOR cover may be hopelessly inadequate in UK, depending where you were! The UK VOR coverage is surprisingly sparse in places and still strongly supplemented by NDBs, so we canot get rid of our ADF sets just yet.

In UK therefore, to refer back to the title of the topic, ADF Receivers....Gone the way of the Dinosaurs? The answer in UK is: DEFINITELY NOT, unfortunately.

[GLSNightPilot]

It seems to an outsider that the dinosaurs are still alive and well in the UK! :p

I think this thread has devolved to a low enough level. I'll give you the last word, and I'm out of here.

[Heliport]

Don't think you'll get many Brits arguing with that - unfortunately!

[Rich Lee]

I say we bring back radio "A" and "N" nav, Great Circle and Rhumb Line routes, Drift Flares, and aircraft sextants for a little celestial navigation.....who needs ADF, VOR, LORAN, Doppler, Inertial Nav, GPS, DGPS or any of that modern stuff?

Let us return to the day when men were men and dildos were made of wood!

[SASless]

Lesseee here....GPS ain't fer use in the UK IFR or VFR.....last time I flogged it from the Ekofisk to Teeside.....ummmm.....about 225 nautical miles as I remember....or 245 Nautical if you left the far side of it.....

In those days we had the use of the last remaining Consol station and that wonderful piece of kit known as "That f.......king Decca!" to find our way home. We had our ADF and two VOR's or was just one.....and a very reliable if not hi-tech eyeball that saw through cloud and dark.

Our game plan back then in the event of nav failure (that being defined as losing the all seeing eyeball.....and the ADF) was to descend to visual contact with the water.....assuming visual came before actual......no radalts for us boyo....uh uh.....not us....just a third baralt.....only the Norwegians needed that kind of stuff.

Now the question ShyT....Shytorque.....sorry for the stutter....

What do you use now for an area nav? and......What do yer plans call for if it goes Tango Uniform on you? Do you take yer fancy Pumer to 10,000 feet and holler for radar vectoring?