So what do you do if the NDB or ADF fails on an NDB approach?
Exactly. That argument makes no sense.
It is to save time and cost in procedure design
This seems to be the defacto position but makes no sense either. Why not just using the existing NDB missed procedure design, but using a GPS waypoint.
It makes no sense, period.
When the NDB at Shoreham was U/S due to the Hunter crash, there were no instrument approaches available at all for about a week. Crazy.
Antony Q
I think a good look at the ILS 29 at EBAW would suggest that with both An NDB and two marker beacons a CAT 1 ILS can be safely flown without using the ILS DME but the procedure clearly assumes that two DME’s are available to the crew as is normal practice in most airliners.
Jason C / NC Yankee
While not nessesaraly agreeing with the need for a conventional aid for the missed approach on a GPS approach. I am sure the thinking is that a system failure in more likely with an aid that transmits a signal strength that is below background noise and comes from a satellite a long way away rather than a simple transmitter on the field that has back up power.
What I do see in GA is a growing trend to depend totally on GPS navigation with a reluctance to refer to conventional radio aids, I would have thought that safety is assured by cross checking between types of navigation aid. One of the great fetures of my old KLN89B GPS was a page that gave the radial and distance from the nearest VOR/DME, using this page and the conventional radio kit on the aircraft to check all was well was very reassuring when about to fly a GPS approach.
I fail to undersand why those who have paid a great deal for an aircraft are so apposed to paying a little more for an ADF & DME so they can fly all almost all approaches in Europe leagaly ?
Being reluctant to use devices like ADF and DME is probably due to ergonomics and user experience provided by the pure software based integrated systems that rely on GPS. In those there is support for a remotely mounted DME but it’s not being used to find an absolute position via DME/DME. So to do everything with GPS and go for the increasing number of SBAS approaches (LPV) instead makes sense.
Back to the STARNAV !
In the early days of GPS Narco produced a multi-sensor box that used GPS, VOR, ILS & DME ( and LORAN if you wished). It was a true airline style navigating box with built in redundancy.
Unfortunately the whole of GA ignored this bit of kit, no doubt blinded by the showroom performance of the early GPS units, the pity is that GA area navigation is now dependent on just one system.
It seems to cope rather OK though.
I fail to undersand why those who have paid a great deal for an aircraft are so apposed to paying a little more for an ADF & DME so they can fly all almost all approaches in Europe leagaly ?
The ADF does provide nice situational awareness, especially combined with a DME, but you also get this with a decent MFD or GPS.
Quite a few approaches which require an NDB on the missed approach can be flown legally in a Radar environment by just requesting different missed approach instructions. ATC can also give you a DME readout for glide slope checking.
Today if an aircraft does not have an ADF it is unlikely that an owner would fit one, and I know several owners who have removed them. If you have the old external antenna it’s probably worth a few extra knots removing the ADF.
The UK IR teaching environment loves NDB procedures, and I enjoy teaching them, conversely not enough time is spent on briefing GPS and Autopilot. Why does this remind me of lessons in U.K. economic history?
ortac wrote:
This seems to be the defacto position but makes no sense either. Why not just using the existing NDB missed procedure design, but using a GPS waypoint.
Apparently if you use a GPS waypoint you will need a more comprehensive survey as the requirements for a missed approach based on one are different. I am not saying it makes sense, merely that is apparently why they are used.
AnthonyQ wrote:
Do you have two DME units? If not, do you re-identify the Station each time you switch between the two? Or do you use my recently discredited method of identifying both wellin advance and using the DME source switch and/or remote/freq switch?
Well I do because the G1000 identifies them.
A_and_C wrote:
I fail to undersand why those who have paid a great deal for an aircraft are so apposed to paying a little more for an ADF & DME so they can fly all almost all approaches in Europe leagaly ?
I like DME and would always install it. ADF is not needed and is pointless to install in my view. You can always ask for a different missed approach not requiring ADF. You will lose out on the ability to listen to the AM radio however which was my main use for having one installed in the past.
I agree that some pilots can be too reliant on GPS for all aspects of flight but I think NDB approaches should be consigned to history. They can be simply and reliably replaced with GPS LNAV approaches which are easier to fly, more accurate and not reliant on SBAS availability. I think they are a great flying challenge but so were radio ranges.
. I think they are a great flying challenge but so were radio ranges.
The quote button on iPad is a bit clunky so apologies for quoting without naming the source – JasonC in this case.
Arguably the four course ranges were easier than an NDB, although very crude on situational awareness – it took some manoeuvring to figure out which quadrant you were in, assuming there were no CBs nearby. Once on the ‘beam’ they may actually have been easier to fly than an NDB, with no mantras to learn such as ‘I am on a QDR of x, but want a QDR of y, my QDR is less/more, therefore I need to steer more/less etc etc’.
I think they may also have been more reliable (signal interference from CBs/static aside) with less mountain or coastal effect? Although the signal frequency was the same.
The ALAR project (Flight Safety Foundation project to reduce approach and landing accidents) identified the NDB approach as significantly more risky. Hopefully they will be phased out in due course.
You also need someone to remember to switch the generator on: Pacific Western lost a C-130 in Zaire in 1976 as the airport had failed to turn the lights and NDB on – not sure why they didn’t divert.
RobertL18C wrote:
You also need someone to remember to switch the generator on:
I think this is what doomed Amelia Earhart and Fred Noonan as well…
In the early days of GPS Narco produced a multi-sensor box that used GPS, VOR, ILS & DME ( and LORAN if you wished). It was a true airline style navigating box with built in redundancy.
The problem with that is that any diligent design of such a box has to discard the navaid once out of its DOC (documented operational coverage i.e. official range). So, take the EGKA DME, which is a really nice unit which was chucked out by Heathrow Airport and which can be picked up from 5000ft and past Caen, 95+ nm away. I guess its DOC is deep in the AIP somewhere but sure as hell it isn’t 95nm. Being a TDME it might be say 20nm, or even less in certain quadrants (due to terrain). And there is a good reason for this: there is another DME in N France on 109.95 also… So, in real GA flight, OCAS, there aren’t going to be many navaids which such a box would use. Accordingly, most of the (ageing 
) GA pilots who actually use a KNS80 are setting it up for navaids well outside their DOC and saying how wonderful it is but they would fail their IR test if they did that on it.
In the USA they still have most of their VOR based airway network intact, but many European IFR routes are based on virtual waypoints so there aren’t many VORs. Plus a KNS80 type box doesn’t work unless the VOR and DME are co-located, which makes it useless in most of France where most VORs don’t have a DME (they seem to have put some in in the last few years).
ATC’s route assignment of VORs as waypoints at ranges of several times the DOC is just another case of the emperor being start naked for the last 20 years
IMHO the best one could do is a dual-DME box (a single DME retuned as required) like jets use for their INS fix-ups. Apart from yet another database subscription to pay for, I can’t see why such a box would not sell, and the logical way would be to integrate it (it would be just software, plus a comms interface for remotely tuning a KN73 or similar) into a GPS like a GNS/GTN.
Then your existing user interface remains. People pay for “convergence” in their life… not for yet another $10k box to take up space in their panel and which won’t be used unless GPS packs up.
But there is an extra issue: you still have to implement the DOC range limiting, and jets get away with this by having continuous nav via INS. GA has no continuous nav. Only GPS gives you that. Non-INS solutions (e.g. MEMS) are too crappy by a factor of 10x to 100x to do the job.
Unfortunately the whole of GA ignored this bit of kit, no doubt blinded by the showroom performance of the early GPS units, the pity is that GA area navigation is now dependent on just one system.
Also most things Narco made were crap
