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

[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,

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In fact there has been a very recent proposal by the CAA to legislate against "unpublished" approaches at airfields.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.

[Blue Rotor Ronin]

Hmmmm

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.

[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]

HMmmm

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!)

[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 , 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 )

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

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?

[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!

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!